CZ20004654A3 - Cyclic analogs of somatostatin - Google Patents

Abstract

New cyclic analogs of somatostatin containing in the molecule an imidazole group representing cis amidic bond, which binds selectively to different somatostatin receptors, and which can therefore be used for the manufacture of pharmaceutical compositions suitable for the treatment of a variety of somatostatin-related diseases in the body.

Description

Technical area

The invention relates to cyclic derivatives containing an imidazole mimetic cisamide bond that selectively bind to somatostatin receptor subtypes. The invention further relates to methods for preparing the compounds of the invention.

State of the art

Somatostatin (SRIF) is a cyclic tetradecapeptide hormone containing a disulfide bridge between positions 3 and 14 and having the ability to inhibit the release of growth hormone (GH) and thyroid-stimulating hormone, and also having the ability to inhibit the release of insulin and glucagon and to reduce gastric secretion. Metabolism of somatostatin by amidopeptidases and carboxypeptidases results in a short duration of action.

Somatostatins bind to five distinct receptor subtypes (SSTRs) with relatively high affinity for each subtype. The smaller, more rigid analogs of the present invention exhibit high selectivity for some of the receptor subtypes. Binding to the various types of somatostatin subtypes has been associated with the treatment of the following diseases. Activation of types 2 and 5 is associated with growth hormone suppression and more specifically with GH secretory adenomas and TSH adenomas. Activation of type 2, but without activation of type 5, is associated with the treatment of prolactin-secreting adenomas. Other indications associated with the activation of somatostatin subtypes are retinosis, inhibition of insulin and/or glucagon and more specifically diabetes mellitus, hyperlipidemia, insulin insensitivity, syndrome X, angiopathy, proliferative retinopathy, Down syndrome and nephropathy, inhibition of gastric acid secretion and more specifically peptic ulcers, enterocutaneous and pancreaticocutaneous fistulas, irritable bowel syndrome, dumping syndrome, watery diarrhea syndrome, AIDS-induced diarrhea, chemotherapy-induced diarrhea, cancer treatment such as hepatomyositis, inhibition of angiogenesis, treatment of inflammatory diseases such as arthritis, chronic graft rejection, angioplasty, graft rejection and gastrointestinal bleeding. Somatostatin agonists can also be used to reduce body weight in patients.

I • ..·· ··· • · · · · ···· · ·· »·· ··· ······· ·· ··· ·· ···

Somatostatin agonists have been reported to be useful in inhibiting the proliferation of Helicobacter pylori.

The essence of the invention

In one aspect, the present invention provides a compound of formula I,

O

O) or a pharmacologically acceptable salt thereof, wherein Y and Z are each independently D- or L- a natural or unnatural α-amino acid; n are independently 0 to 50, provided that both n cannot be 0 at the same time; m is 0 or an integer from 1 to 10;

a is H or R ¹ ;

is OH, -OR ¹ or -NR ⁹ R ⁹ ;

or a together with b forms an amide bond;

R ¹ is independently H, (C 1 -C ₄ )alkyl or aryl(C 1 -C ₄ )alkyl;

R ² is H or an optionally substituted group selected from the group consisting of (C 1 to C 4 )alkyl, phenyl, phenyl(C 1 to C 4 )alkyl or heterocyclyl(C 1 to C 4 )alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents each independently selected from the group consisting of (C 1 to C 4 )alkyl, (C 3 to C 10 )cycloalkyl, -OR ⁶ , -S(O)qR ⁷ , -N(R ⁹ R ⁹ ), -NHCO-R ⁶ , -NHSO2R ⁹ , -CO2R ⁹ , -CONR ⁹ R ⁹ and -SO ₂ NR ⁹ R ⁹ , where q is 0, 1, 2 or 3;

R ³ and R ⁴ are each independently H, halo or an optionally substituted group selected from the group consisting of (C 1 to C ₄ )alkyl, (C ₃ to C ₈ )cycloalkyl, aryl and aryl(C 1 to C ₄ )alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents selected from the group consisting of OH, (C 1 to C ₄ )alkyl, (C 1 to C ₄ )alkoxy, aryloxy, aryl(C 1 to C ₄ )alkoxy, N(R ⁹ R ⁹ ), -COOH, -CONR ⁹ R ⁹ and halo;

or R ³ and R ⁴ are taken together with the carbons to which they are attached to form an optionally substituted aryl, wherein the aryl is optionally substituted with one or more substituents independently selected from the group consisting of OH, (C 1 -C ₄ )alkyl, (C 1 -C ₄ )alkoxy, aryloxy, aryl(C 1 -C ₄ )alkoxy, -NR ⁹ R ⁹ , -COOR ⁵ , -CONR ⁹ R ⁹ and halo;

R ⁵ at each occurrence is independently H or is an optionally substituted group selected from the group consisting of (C 1 -C ₄ )alkyl, OH, (C 1 -C ₄ )alkoxy, aryloxy, NO ₂ , aryl(C 1 -C ₄ )alkoxy, NR ⁹ R ⁹ , -COOH, -CONR ⁹ R ⁹ , and halo;

R ⁶ at each occurrence is independently selected from the group consisting of H, (C 1 to C ₄ )alkyl, (C 1 to C ₄ )alkoxy, aryl(C 1 to C ₄ )alkyl, and aryl(C 1 to C ₄ )alkoxy,

R ⁷ is H when q is 3 or R ⁷ at each occurrence is independently selected from the group consisting of (C 1 to C ₄ )alkyl, aryl or aryl(C 1 to C ₄ )alkyl when q is 0, 1 or 2, and

R ⁹ at each occurrence is independently selected from the group consisting of H, NO ₂ , (C 1 -C ₄ )alkyl, aryl, and aryl(C 1 -C ₄ )alkyl.

A preferred compound of general formula I is the compound H-Trp-D-Trp-Lys-Abu-Phe Ψ (4-methoxyphenyl)imidazole)-Gly-OH.

In another aspect, the invention provides a compound of formula II,

or a pharmaceutically acceptable salt thereof, wherein Y and Z are each independently D- or L- a natural or unnatural α-amino acid; m is 0 or an integer from 1 to 10; n is for each occurrence independently 0 to 6, is OH, -OR ¹ or -NR ⁹ R ⁹ ;

R ¹ at each occurrence is independently H, (C 1 -C ₄ )alkyl or aryl(C 1 -C ₄ )alkyl;

R ² is H or an optionally substituted group selected from the group consisting of (C 1 to C ₄ )alkyl, phenyl, phenyl(C 1 to C ₄ )alkyl or heterocyclyl(C 1 to C ₄ )alkyl, where the optionally substituted group

is optionally substituted with one or more substituents each independently selected from the group consisting of ⁽ C1- _C4 )alkyl, cycloalkyl, ^-OR6 , -S(O) ^qR7 , -N( ^R9R9 ), ^{-NHCO-R6 ,} NHSO2R9, ^-CO2R9 , ^-CONR9R9 and ^-SO2NR9R9 , where q is 0, 1, 2 or ^{3 ;}

R ³ and R ⁴ are each independently H, halo or an optionally substituted group selected from the group consisting of (C 1 -C ₄ )alkyl, cycloalkyl, aryl and aryl(C 1 -C ₄ )alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents selected from the group consisting of OH, (C 1 -C ₄ )alkyl, (C 1 -C ₄ )alkoxy, aryloxy, aryl(C 1 -C ₄ )alkoxy, -N(R ⁹ R ⁹ ), COOH, -CONR ⁹ R ⁹ and halo;

or R ³ and R ⁴ are taken together with the carbons to which they are attached to form an optionally substituted aryl, wherein the aryl is optionally substituted with one or more substituents independently selected from the group consisting of OH, (C 1 -C ₄ )alkyl, (C 1 -C ₄ )alkoxy, aryloxy, aryl(C 1 -C ₄ )alkoxy, -NR ⁹ R ⁹ , -COOR ⁵ , -CONR ⁹ R ⁹ and halo;

R ⁵ at each occurrence is independently H or is an optionally substituted group selected from the group consisting of (C 1 -C ₄ )alkyl and aryl(C 1 -C ₄ )alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents, each independently selected from the group consisting of (C 1 -C ₄ )alkyl, OH, (C 1 -C ₄ )alkoxy, aryloxy, aryl(C 1 -C ₄ )alkoxy, -NR ⁹ R ⁹ , -COOR ⁵ , -CONR ⁹ R ⁹ and halo;

R ⁶ at each occurrence is independently selected from the group consisting of H, (C 1 to C ₄ )alkyl, (C 1 to C ₄ )alkoxy, aryl(C 1 to C ₄ )alkyl and aryl(C 1 to C ₄ )alkoxy,

R ⁷ is H when q is 3 or R ⁷ at each occurrence is independently selected from the group consisting of (C 1 to C ₄ )alkyl, aryl or aryl(C 1 to C ₄ )alkyl when q is 0, 1 or 2, and

R ⁹ at each occurrence is independently selected from the group consisting of H, NO ₂ , (C 1 -C ₄ )alkyl, aryl, and aryl(C 1 -C ₄ )alkyl.

X ¹ is a natural or unnatural D- or La-amino acid, where X ¹ is Phe, Nal, Trp, Tyr, Pal or His, the aromatic ring of which is optionally substituted on carbon or nitrogen by a substituent R ⁶ or when Ser or Thr the side chain oxygen is optionally substituted with one or more R';

X ² is D- or L-Trp, N-methyl-D-Trp or N-methyl-L-Trp;

X ³ is Lys, α-N-methyl-Lys or ε-Ν-(C 1 to C ₄ )alkyl-Lys or eN-[aryl-(C 1 to C ₄ )alkyl]-Lys;

X ⁴ is a natural or unnatural D- or La-amino acid, where X ⁴ is Phe, Nal, Trp, Tyr or His, the aromatic ring of which is optionally substituted on carbon or nitrogen by a substituent R ⁸

or when X ⁴ is Ser, Tyr or Thr, the side chain oxygen may be substituted with one or more R ¹ substituents.

The bonds between X ¹ , X ² , X ³ and X ⁴ are amide bonds as are the bond between X ¹ and Z and the bond between X ⁴ and Y.

A preferred group of compounds of formula II, designated A, is one wherein each n is 2, m is 0 or 1 to 5,

R ¹ at each occurrence is independently H, methyl or aryl(C 1 to C ₄ )alkyl,

R ² is an optionally substituted group selected from the group consisting of phenyl-(C 1 to C ₄ )alkyl, and heterocyclyl-(C 1 to C ₄ )alkyl, wherein the optionally substituted group is substituted with a substituent selected from the group consisting of (C 1 to C ₄ )alkyl and -OR ⁶ and

R ³ and R ⁴ are each independently H, halo or an optionally substituted group selected from the group consisting of (C 1 to C ₄ )alkyl and aryl, wherein the optionally substituted group is optionally substituted with a substituent selected from the group consisting of OH, (C 1 to C ₄ )alkoxy, aryloxy and halo.

A preferred group B in group A compounds of the present invention is one where X ¹ is Phe, Nal, Trp, Tyr, Pal or His, where the aromatic ring is optionally substituted on carbon or nitrogen with a substituent R ⁶ , and

X ⁴ is Val, Abu, Ser, Thr, Nal, Trp, Tyr or His, where the aromatic ring in Nal, Trp, Tyr and His is optionally substituted on carbon and/or nitrogen by a substituent R ⁸ or where X ⁴ is Ser, Tyr or Thr, the oxygen in the side chain of which is optionally substituted by a substituent R ¹ .

A preferred group C in the group of compounds B is one where X ¹ is Phe, Trp or Tyr, the aromatic ring of which is optionally substituted on carbon or nitrogen by a substituent R ⁶ ,

X ² is D-Trp or N-methyl-D-Trp,

X ³ is Lys or αN-methyl-Lys,

X ⁴ is Val, Thr, Abu, Nal or Tyr, where the oxygen in the side chain hydroxyl group of Thr and Tyr is optionally substituted with R ¹ ;

R ¹ is independently, for each occurrence, H, methyl or benzyl;

R ² is an optionally substituted group selected from the group consisting of phenylmethyl and heterocyclylmethyl, wherein the optionally substituted group is substituted with a substituent selected from the group consisting of (C 1 -C ₄ )alkyl and -OR ⁶ ;

R ³ is (C 1 to C ₄ )alkyl or optionally substituted aryl, wherein the optionally substituted aryl is substituted with a substituent selected from the group consisting of OH, (C 1 to C 4 )alkoxy, aryloxy and halo;

R ⁴ is H, and

R ⁶ is independently selected for each occurrence from the group consisting of H and aryl(C 1 -C ₄ )alkoxy.

A preferred group D in compound group C is one where X ¹ is Phe, Trp, Tyr or Tyr(Obzl);

X ⁴ is Val, Thr, Abu, Nal or Tyr, wherein the hydroxy group in Thr and Tyr is optionally substituted with benzyl;

M is 0, 2 or 4;

R ² is an optionally substituted group selected from the group consisting of phenylmethyl or 3-indolylmethyl, wherein the optionally substituted group is optionally substituted with -OR ⁶ ; and R ³ is 1,1-dimethylethyl or optionally substituted aryl, wherein the optionally substituted aryl is optionally substituted with a group selected from the group consisting of OH, (C 1 to C ₄ )alkoxy and halo.

A preferred group E from the group of compounds D is one where R ² is phenylmethyl;

R ³ is 1,1-dimethylethyl or optionally substituted phenyl, wherein the optionally substituted phenyl is optionally substituted with OH or OCH ₃ and

R ⁶ is independently selected for each occurrence from the group consisting of H or benzylmethoxy.

The preferred group F from the group of compounds E is:

Cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-Methoxyphenyl)imidazole)-GIy], Cyclo [Tyr(OBzl)-D-Trp-Lys-Val-Phe Ψ (4-(3-Methoxyphenyl)imidazole)-Gly], Cyclo [Trp-D-Trp-I ys-Val-Phe Ψ (4-(3-Methoxyphenyl)imidazole)-Gly], Cyclo [Trp-D-Trp-1 ys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Thr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidamle)Gly], cyclo [Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Abu-Phe Ψ (4-(3-Methoxyphenyl)imidazole)-Gly), cyclo [Phe-D-Trp-I ys-Tyr(OBzl)-Phe Ψ (4-(1, l-dimethylethyl)imidazole-Gly], cyclo [Phe-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole-Gly), cyclo [Phe-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazol-Gly], cyclo [Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(3-methoxyphenyl)imidazoh-Gly], cyclo [Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(3-hydroxyphenyl)imidazol-Gly], cyclo [Trp-D-Trp-lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazol-Gly), • · · · · · • · · · · · • · · · · · · · • · · · · · · · · ·· ·· · cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Glyj, cyclo [Phe-D-Trp-Lys-Nal-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe Ψ (4-(3-methoxyphenyl)imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(3-rethoxyphenyl)imidazole (y)Abu), cyclo [Trp-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(4-methoxyphenyl)imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(phenyl)imidazole-Gly)] [Trp-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-(r:)Ahx] and cyclo [Trp-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(3-hydroxyphenyl)imidazole-(y)Abu).

A preferred skyline group of compounds F, referred to as group G, is cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)irnidazoh)-Gly], cyclo [Tyr(OBzl)-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly, cyclo [Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole}-Gly], cyclo [Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazoh)-Glyj, cyclo [Trp-D-Trp-Lys-Thr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gfy], cyclo [Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-Hydroxyphenyl)imidazoh)-Gly], cyclo [Trp-D-Trp-Lys-Abu-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Phe-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(1, l-dimethylethyl)imidazole-Gly], cyclo [Phe-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole-Gly]), cyclo [Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Gly] and cyclo [Tyr-D-Trp-Lys-VahPhe Ψ (4-(3-hydroxyphenyl)imidazole-Glyj.

A preferred group of compounds G, referred to as group H, is cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Yal-Phe Ψ (4-(3-hydroxyphenylimidase)-Gly], cycto [Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Abu-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Phe-D-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole-Gly] or cyclo [Tyr-D-Trp-Lys-Yal-Phe Ψ (4-(3-hydroxyphenyl)imidazole-GlyJ.

A preferred group of compounds H, referred to as group I, is cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Trp-D-Lys-Va e Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], ······· «· ··· fl* cyclo [Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly] and cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly].

Another preferred group of F compounds, referred to as group J, is cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Glyj, cyclo [Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Thr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Abu-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly], [Phe-D-Trp-lys-Tyr(OBzl)-Phe Ψ (4-(1,1 -dimethylethyl)imidazole-Gly], cyclo [Phe-D-Trp-ty ys-Tyr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-Gly], cyclo [Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Gly], cyclo [Trp-D-Trp-I ys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-Glyj, cyclo [Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Gly], cyclo [Phe-D-Trp-I ys-Nal-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe Ψ (4-(3-Methoxyphenyl)imidazole-Gly], Cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-Methoxyphenyl)imidazole-( )Abu], Cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(4-Methoxyphenyl)imidazole-Gly], Cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(phenyl)imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-(8)Ahx] and cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-hydroxyphenyl)imidazole-( )Abu].

A preferred group of compounds J, referred to as group K, is cyclo [Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly], cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe Ψ (4-(3-hydroxyphenyl)imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-(y)Abu], cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(4-methoxyphenyl)imidazole-Glyj or cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(phenyl)imidazole-Glyj).

A preferred group of compounds K, referred to as group L, is cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazoie-Glyj, cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole-(Y)Abu], ·· ··· ·· ··· cyclo [Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(4-methoxyphenyl)imidazole-Gly] and cyclo (Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(phenyl)imidazole-Gly).

In another aspect, the present invention provides a pharmaceutical composition comprising an effective amount of a compound of formula I or formula II, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

In another aspect, the present invention provides a method of eliciting the effect of a somatostatin receptor agonist in a mammal, which comprises administering to said mammal an effective amount of a compound of formula I or II, or a pharmaceutically acceptable carrier thereof.

In another aspect, the present invention provides a method of eliciting the effect of a somatostatin receptor antagonist in a mammal, which comprises administering to said mammal an effective amount of a compound of formula I or II, or a pharmaceutically acceptable carrier thereof.

In another aspect of the present invention, there is provided a method of treating prolactin adenoma, diabetes mellitus, hyperlipidemia, insulin insensitivity, Syndrome X, angiopathy, proliferative retinopathy, Down syndrome, neuropathy, gastric acid secretion, peptic ulcers, enterocutaneous and pancreaticocutaneous fistulas, irritable bowel syndrome, dumping syndrome, watery diarrhea syndrome, AIDS-induced diarrhea, chemotherapy-induced diarrhea, acute or chronic pancreatitis, hormone-secreting gastrointestinal tumors, cancers, hepatomas, angiogenesis, inflammatory diseases, arthritis, chronic graft rejection, angioplasty, graft hemorrhage or gastrointestinal bleeding in mammals, which comprises administering a compound of formula I or II or a pharmaceutically acceptable salt thereof to said mammal.

In another aspect of the present invention, there is provided a method of inhibiting the proliferation of heliobacter pylori in mammals, which comprises administering to said mammals a compound of formula I or II, or a pharmaceutically acceptable salt thereof.

In another aspect of the present invention, there is provided a process for the production of a compound of the general formula

H-N’

R ¹ χ-W.— Ν' ( «%· o=c '~v'” o

(and)

(ii)

which includes deprotection of compounds of the formula

by cleavage of the Prt group, where

Prt is a protecting group of the amino acid chain,

Y and Z are each independently a D- or L-natural or unnatural α-amino acid, optionally having a protected side chain, where H-N* is the amino group of the N-terminal amino acid defined by Y and O=C* is the carboxyl group of the C-terminal amino acid defined by Z;

n for each occurrence is independently 1 to 50;

and all other variables are the same as defined above in general formula I.

In another aspect, the present invention provides a method for preparing a compound of the formula

which includes

<γ-Ρη)„—Ν' . tyty

HOOC (ΦΑ. ^R λν <tf) for compounds of formula a, formation of an amide bond between the terminal amino group of the last amino acid defined by Y and the terminal carboxyl group of the last amino acid defined by Z, by reacting a compound of general formula a' with a peptide coupling agent and an additive; or for compounds of formula b, formation of an amide bond between the terminal amino group and the terminal carboxyl group of the last amino acid defined by Z, by reacting a compound of general formula b' with a peptide coupling agent and an additive; or for compounds of formula c, formation of an amide bond between the terminal amino group of the last amino acid defined by Y and the terminal carboxyl group, by reacting a compound of general formula c' with a peptide coupling agent and an additive;

where Prt is an amino acid side chain protecting group;

Y and Z are each independently D- or L-natural or unnatural α-amino acids, optionally having a protected side chain, where H-N* is the amino group of the N-terminal amino acid defined by Y and O=C* is the carboxyl group of the C-terminal amino acid defined by Z;

n for each occurrence is independently 1 to 50;

all other variables are the same as in the above definition of the compound of general formula I.

In another aspect, the present invention provides a method for preparing a compound of the formula

R°

which involves the reaction of a compound of general formula f with an α-haloketone of formula

X'-CH(R ³ )CO(R ⁴ ) in the presence of a base and a polar aprotic solvent until the reaction is complete, evaporating the polar aprotic solvent to form a solid, dissolving the solid in an aprotic organic solvent and an excess amount of aqueous NH ₄ OAc to form a solution, and boiling the solution while removing the polar layer to form a compound of formula A, where

X is an amino protecting group,

X’ is halo, and the other variables are the same as defined above for formula I.

In another aspect, the present invention provides a process for the preparation of a compound of formula I, which comprises coupling a compound of formula B with an unprotected amino acid, (Prt)-Y, wherein the unprotected amino acid is in the form of its activated ester, anhydride or acid halide, in the presence of a base to a practical extent.

·· 0 00 0 • 0 · 0 00 0 0 0 0

0 0 0 0 0 0

0 0 0 000 0 0

000 000

000 0000 00 000 0· ··· carrying out the reaction to form a compound of general formula C, optionally deprotecting the amino group N _and the -protected amino acid, (Prt)-Y, using conventional deprotection reactions and repeating the coupling reaction with another unprotected amino acid until the desired product of general formula I is obtained;

Y is, for each occurrence, independently a D- or L-natural or unnatural α-amino acid having a side chain with a protecting group;

Prt is an amino protecting group,

R' is an alkyl ester or benzyl ester, n is 1 to 100;

and all other variables are the same as in the above definition of the compound of formula I.

In another aspect, the present invention provides a process for preparing a compound of formula I, as defined above, comprising coupling a compound of formula B, activated as its active ester, anhydride or chloride, with an N-deprotected peptide resin (A'), prepared by methods well known to those skilled in the art of peptide synthesis, removing the N-terminal Fmoc group using piperidine in DMF, TAEA or a similar base, and deprotecting and cleaving the resulting intermediate B' from the resin using a strong acid. All variables are the same as in the definition of compound I above.

r M' ^Rl

Fmoc—N

⁰ B

H,N-(y)n— i resin

AND'

In another aspect, the present invention provides a method for preparing a compound of formula I comprising coupling a compound of formula B, activated as its active ester, anhydride or halide, with an N-deprotected peptide resin (H), prepared by a method well known to those skilled in the art of peptide synthesis, deprotecting the N-terminal Fmoc group using piperidine in DMF, TAEA or a similar base, acylating the deprotected N-terminal amino group with an N _- Fmoc-protected amino acid x using a peptide coupling reaction well known to those skilled in the art, repeating the base deprotection and coupling step as necessary until additional

99 9

9 9 ··

9 9 9

9 9 9 9

9 9 9

999 99 9*9

99 9* •9 · 9 » » • >99 • · 9 9 9 • · 9 9 ««9 9«9· 99 amino acids x, deprotection and cleavage of the resulting intermediate C’ from the resin using a strong acid. All variables are the same as in the above definition of the compound of general formula I.

In another aspect, the present invention provides a process for preparing a compound of formula I comprising coupling a compound of formula B, activated as its active ester, anhydride or halide, with an amino-substituted resin such as Tris-(alkoxy)-benzylamine resin (PAL resin), 4-(2',4'-dimethoxyphenylaminomethyl)phenoxy resin (N-deprotected Rink resin) or benzhydrylamine resin, deprotecting the N-terminal Fmoc group using piperidine in DMF, TAEA or a similar base, acylating the released N-terminal amino group with an N- _and -Fmoc-protected amino acid x using a peptide coupling reaction well known to those skilled in the art, repeating the base deprotection and coupling step as necessary to incorporate additional amino acids x, deprotecting and cleaving the resulting intermediate D' from the resin using a strong acid, and all other variables being the same as in the definition of compound I above.

In another aspect, the present invention provides a process for the preparation of a compound of formula I comprising reacting a compound of formula B with a base such as Cs ₂ CO ₃ , reacting the resulting phenolic cesium salt E' with a halomethylated polystyrene resin such as Merrifield peptide resin, removing the Fmoc protecting group with piperidine or a similar organic base, acylating the released N-terminal amino group with an N _and -Fmoc protected •· φ · · φφφ · ··· φ φφφφ φφφ • ΦΦΦ· ΦΦΦΦ ·

ΦΦΦΦΦ Φ · Φ

ΦΦΦ ΦΦΦΦ «· ΦΦΦ ·Φ ΦΦΦ with the amino acid χ using a coupling reaction well known to those skilled in the art, repeating the deprotection and coupling step as necessary until additional amino acids x are incorporated, deprotecting the final protected peptide sequence at the N-terminus with piperidine or a similar organic base and at the C-terminus with Tfa, cyclizing the resulting intermediate F’ using a coupling reaction well known to those skilled in the art, and cleaving the resulting intermediate G’ from the resin using a strong acid. All variables are the same as in the definition of Formula I above.

E P

In another aspect, the present invention provides a process for preparing a compound of formula I, as defined above, comprising combining a compound of formula B, activated as its active ester, anhydride or halide, with an N-deprotected peptide resin A', prepared by methods well known in the art, deprotecting the N-terminal Boc group using Tfa and deprotecting the side chain protecting groups, and cleaving the resulting intermediate H' from the resin using a strong acid such as HF. All variables are the same as in the definition of formula I above.

In another aspect, the present invention provides a method for preparing a compound of formula I comprising coupling a compound of formula B, activated as an active ester, anhydride or acyl halide, with an N-deprotected peptide resin H prepared by methods well known in the art, deprotecting the N-terminal Boc group using Tfa, acylating the released N-terminal amino group with an N _- a-Boc-protected amino acid x using a peptide coupling reaction well known to those skilled in the art, repeating the Tfa deprotection and coupling step as necessary until additional amino acids x are introduced, deprotecting and cleaving the resulting intermediate Γ from the resin using a strong acid. All variables are the same as in the definition of formula I above.

H-(x|n—N

In another aspect, the present invention provides a method for preparing a compound of formula I comprising reacting a compound of formula B with a base such as Cs ₂ CO ₃ , reacting the resulting phenolic cesium salt J' with a halomethylated polystyrene resin such as Merrifield peptide resin, removing the Boc protecting group with Tfa, acylating the released N-terminal amino group with an N-Boc protected amino acid x using a coupling reaction well known to those skilled in the art, repeating the Tfa deprotection and coupling step as necessary until additional amino acids x are incorporated, deprotecting the final protected peptide sequence at the N-terminus with Tfa and at the C-terminus with an inorganic base such as LiOH in aqueous DMF, cyclizing the resulting intermediate K' using a peptide coupling reaction well known to those skilled in the art, and cleaving the resulting intermediate L' from the resin using a strong acid. All variables are the same as in the definition of formula I above.

In another aspect, the present invention provides a method for preparing a compound of formula 1 comprising coupling a compound of formula B, activated in the form of its active ester, anhydride or acyl halide, with an N-deprotected peptide 4-nitrobenzophenone oxime resin M', prepared by methods well known in the art, deprotecting the N-terminal Boc group • ·» ·· * ·· · «· · · · · · · · · · · · · • · * · « · · · · • · · * · *·· · · ··· · · · · ·» 94 9 using Tfa, acylating the released N-terminal amino group with an N _a -Boc-protected amino acid x using a peptide coupling reaction well known to those skilled in the art, repeating the Tfa deprotection and coupling step as necessary until additional amino acids x are introduced, deprotecting the N-terminal Boc group with Tfa, cyclizing and cleaving the resulting N'-deprotected intermediate N' by neutralization with a suitable organic base and removal of the side chain protecting groups using a strong acid such as HF. All variables are the same as in the definition of Formula I above.

M'

Detailed description

The term heterocycle as used herein refers to any heterocycle that may occur in the side chain of an amino acid. Examples include, but are not limited to, such heterocycles as benzothienyl, coumaryl, imidazolyl, indolyl, purinyl, pyridyl, pyrimidinyl, quinolinyl, thiazolyl, thienyl, and triazolyl.

The term aryl as used herein refers to any stable monocyclic or bicyclic carbon ring of up to seven members in each ring, where at least one ring is aromatic. Examples of aryl groups include biphenyl, indanyl, naphthyl, phenyl and 1,2,3,4-tetrahydronaphthalene.

Several abbreviations are used in this invention for amino acid components, certain preferred protecting groups, reagents, and solvents. The meanings of these abbreviations are given in Table 1.

Abbreviated designation Significance Amino acids His L-Histidine Lys L-Lysine Nal L-3-(2-naphthyl)alanine Phe L-Phenylalanine

Shit L-Serine Thr L-Threonine Suffering L-Tryptophan (unless otherwise stated) Tyr L-Tyrosine Ahh 6-Aminohexanoic acid Protective groups Sorry 1,1-(Dimethylethoxy)carbonyl Cbz Benzyloxycarbonyl Fmoc 9-Fluorenylmethoxycarbonyl 1 Trout Triphenylmethyl Solvents DMF N,N-dimethylformamide THF T etrahydrofuran EtOAc Ethyl acetate Reaction reagents Tfa Trifluoroacetic acid NMM 4-methylmorpholine DIEA Diisopropylethylamine TEA Triethylamine TAEA Tris(2-aminoethyl)amine HOAT 1 -Hydroxy-7-azabenzotriazole HAT [O-(7-azabenzotrazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate EDC 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride DCC Dicyclohexylcarbodiimide

In vitro determination

The affinity of the compound for human somatostatin receptors subtypes 1 to 5 (ssf, sst ₂ , sst ₃ , sst ₄ and sst ₅ ) is determined by measuring the inhibition of [ ¹²⁵ I-Tyr ¹¹ ]SRIF-14 binding to CHO-K1 cells.

The human sst receptor gene was cloned as a genomic fragment. The Pst | -Xmn | segment (1.5 Kb) containing a 5'-untranslated region (100 bp), a 1.17 Kb total coding region, and a 230 bp 3'-untranslated region was modified by adding a BglI | linker. The resulting DNA fragment was subcloned into the BamHI region of pCMV-81 to generate a mammalian expression vector.

« 9 • 9 plasmids (provided by Dr. Graeme Bell of the University of Chicago). A clonal cell line stably expressing the sst receptor was obtained by transfection into CH0-K1 cells (ATCC) using the calcium phosphate precipitation method (1). The plasmid pRSV-neo (ATCC) was included as a selectable marker. Clonal cell lines were selected in RPMI 1640 medium containing 0.5 mg/ml G418 (Gibco), the circle was cloned and expanded in culture.

The human sst ₂ somatostatin receptor gene, isolated as a 1.7 Kb BamH1-Hindi | genomic fragment and subcloned into the plasmid vector pGEM3Z (Promega) was kindly provided by Dr. G. Bell of the University of Chicago). A mammalian cell expression vector was constructed by inserting the 1.7 Kb BamH1-Hindi | fragment into a compatible restriction endonuclease site in plasmid pCMV5. A clonal cell line was obtained by transfection into CHO-K1 cells using the calcium phosphate precipitation method. The plasmid pRSV-neo was included as a selectable marker.

Human sst, was isolated on a genomic fragment and the complete coding sequence was contained in a 2.4 Kb BamHI HindII | fragment. The mammalian expression plasmid pCMV-h3 was constructed by inserting a 2.0 Kb Nco| -Hindi I fragment into the EcoRI site of the pCMV vector after modification of the ends and addition of EcoRI linkers. A clonal cell line stably expressing the sst, receptor was obtained by transfection into CHO-K1 cells (ATCC) using the calcium phosphate precipitation method. The plasmid pRSV-neo (ATCC) was included as a selectable marker. Clonal cell lines were selected in RPMI 1640 medium containing 0.5 mg/ml G418 (Gibco), the circle was cloned and expanded in culture.

The plasmid expressing the human sst ₄ receptor, pCMV-ΗΧ, was provided by Dr. Graeme Bell of the University of Chicago. The vector containing the 1.4 Kb Nhe| -Hne| genomic fragment encoding human sst ₄ , 456 bp of 5'-untranslated region and 200 bp of 3'-untranslated region, was cloned into the XbaI/EcoRI region of PCMV-HX. A clonal cell line expressing the sst ₄ receptor was obtained by transfection into CHO-K1 cells (ATCC) using the calcium phosphate precipitation method. The plasmid pRSV-neo (ATCC) was included as a selectable marker. Clonal cell lines were selected in RPMI 1640 medium containing 0.5 mg/ml G418 (Gibco), the circle was cloned and expanded in culture.

The human _sst5 gene was obtained by PCR using a λ genomic clone as a template and was kindly provided by Dr. Graeme Bell of the University of Chicago). The resulting 1.2 Kb PCR fragment contains 21 base pairs in the 5'-untranslated region, the full coding region, and 55 bp of the 3'-untranslated region. The clone was inserted into the EcoRI site of plasmids pBSSK(+). The insert was

· • 4 ·

4 was regenerated as a 1.2 Kb Hindi IxbaI fragment for subcloning into the pCVM5 mammalian expression vector. A clonal cell line stably expressing the sst ₅ receptor was obtained by transfection into CHO-K1 cells (ATCC) using the calcium phosphate precipitation method. The plasmid pRSV-neo (ATCC) was included as a selectable marker. Clonal cell lines were selected in RPMI 1640 medium containing 0.5 mg/ml G418 (Gibco), the circle was cloned and expanded in culture.

CHO-K1 cells stably expressing one of the human sst receptors were grown in RPMI 1640 containing 10% calf serum and 0.4 mg/ml geneticin. The cells were harvested with 0.5 mM EDTA and centrifuged at 500 g for 5 min at 4 °C. The pellet was dissolved in 50 mM Tris, pH 7.4 and centrifuged twice at 500 g for 5 min at 4 °C. The cells were lysed by sonication and centrifugation at 39,000 g for 10 min at 4 °C. The pellet was resuspended in the same buffer and centrifuged at 50,000 g for 10 min at 4 °C, and the membranes in the resulting pellet were stored at -80 °C.

Comparative inhibition experiments of [ ¹²⁵ I-Tyr ^H ]SRIF-14 binding were performed in duplicate in a 96-well polypropylene plate. Cell membranes (10 pg protein per well) were incubated with [ ¹²⁵ I-Tyr ^H ]SRIF-14 (0.05 nM) for 60 min at 37 °C in 50 mM HEPES (pH 7.4), 0.2% BSA, 5 mM MgCl ₂ , 200 KlU/ml Trasylol, 0.02 mg/ml bacitracin and 0.02 mg/ml phenylmethylsulfonyl fluoride.

Bound [ ¹²⁵ I-Tyr ^H ]SRIF-14 is separated from free by immediate filtration through GF/C glass filter plates (Unifilter, Packard) pre-impregnated with 0.1% polyethylenimine (PEI) using a Filtermate 196 (Packard) cell harvester. The filters are washed with 50 mM HEPES at 0 to 4 °C for 4 sec and determined for radioactivity using a Packard Top Count.

Specific binding is obtained by subtracting non-specific binding (determined in the presence of 0.1 pM SRIF-14) from total binding. Binding data are analyzed using computer nonlinear regression analysis (MDL) and inhibition constant Ki values are determined.

Determining whether a compound of the present invention is an agonist or antagonist is done by the following measurement.

CHO-K1 cells expressing human somatostatin receptor subtypes (SRIF-14) are seeded in 24-well culture plates in RPMI 1640 medium with 10% FCS and 0.4% mg/ml geneticin. The medium is changed the day before the experiment.

Cells at a concentration of 10 ⁵ cells per well are washed twice with 0.5 ml of fresh PMI with

0.2% BSA supplemented with 0.5 mM (1) 3-isobutyl-1-methylxanthine (IBMX) and incubated for min at 37 °C.

• Cyclic AMP production is stimulated by the addition of 1 mM forskolin (FSK) for 15 to 30 min at 37 °C.

• The agonistic effect of the compound is measured by simultaneous addition of FSK (1 μΜ), SRIF-14 (10' ¹² M to 10' ⁶ M) and the test compound (10' ¹⁰ M to 10' ⁵ M).

• The antagonistic effect of the compound is measured by simultaneous addition of FSK (1 μΜ), SRIF-14 (1 to 10 nM) and the test compound (ΙΟ' ¹⁰ M to 10' ⁵ M).

The reaction medium is removed and 200 ml of 0.1 N HCl is added. cAMP is measured using radioimmunoassay (FlashPlate SMP001A Kit, New England Nuclear).

Radioligand binding assay

Membranes for in vitro receptor binding assays were obtained by homogenizing (Polytron, setting 6, 15 s) CHO-K1 cells expressing hsst receptor subtypes in ice-cold 50 mM Tris-HCl and centrifuging twice at 39,000 g (10 min) followed by immediate resuspension in fresh buffer. The final pellets were resuspended in 10 mM Tris-HCl for assay. For the determination of hsstl, hsst3, hsst4, hsst5, aliquots of the membrane preparation were incubated (for 30 min at 37 °C with 0.05 nM [ ¹²⁵ I-Tyr ¹¹ ]SRIF-14 in 50 mM HEPES (pH 7.4) containing BSA (10 mg/ml); MgCl ₂ (5 mM)), Trasylol (200 KlU/ml), bacitracin (0.02 mg/ml) and phenylmethylsulfonyl fluoride (0.02 mg/ml). The final volume for the determination was 0.3 ml.

For hsst2 assay, [ ¹²⁵ I]MK-678 (0.05 nM) was used as the radioligand and incubation was performed for 90 minutes at 25 °C. Incubations were terminated by rapid filtration through GF/C filters (pre-soaked with 0.3% polyethylenimine) using a Brandel filter apparatus. Each tube and filter were then washed three times with 5 ml aliquots of ice-cold buffer.

Specific binding was defined as total radioligand minus ligand bound in the presence of 1000 nM SRIF-14 (hsst1,3,4,5) or 1000 nM MK-678 for hsst2.

The compounds of the present invention can be assayed in vivo for their utility associated with binding to the somatostatin receptor, including specific binding to somatostatin receptor subtypes, according to methods well known to those skilled in the art, such as those described in I. Shimon, et al., "Somatostatin receptor subtype specificity in human fetal pituitary cultures", J. Clin. Invest., vol. 99, issue 4, pp. 789-798, 1997 and C. Gilon et al., "A backbone22 cyclic receptor 5-selective somatostatin analogue: Synthesis, bioactivity and nuclear magnetic resonance conformational analysis", J. Med. Chem., 1998, 41, 919-929.

As is well known to those skilled in the art, the known and potential uses of somatostatin antagonists and/or agonists are numerous and varied. These various uses of somatostatin can be summarized as follows:

Somatostatin agonists can be used to suppress growth hormone and more specifically GH-secreting endomas (acromegaly) and TSH-secreting adenomas; treat prolactin-secreting adenomas, inhibit insulin and/or glucagon and more specifically diabetes mellitus, angiopathy, proliferative retinopathy, Down syndrome and nephropathy; inhibit gastric acid secretion and more specifically gastric ulcers; enterocutaneous and pancreaticocutaneous fistulas, irritable bowel syndrome, chemotherapy-induced diarrhea, acute or chronic pancreatitis and hormone-secreting gastrointestinal tumors; treat cancer such as hepatoma; inhibit angiogenesis; treat inflammatory diseases such as arthritis; retinopathy; chronic graft rejection; angioplasty, prevention of graft rejection and gastrointestinal bleeding.

The present invention therefore also includes the preparation of pharmaceutical compositions comprising as active ingredient at least one compound of the present invention together with a pharmaceutically acceptable carrier.

A compound of the present invention may be administered orally, parenterally (e.g., intramuscularly, intraperitoneally, intravenously, or subcutaneously by injection or implant), nasally, vaginally, rectally, sublingually, or topically, and may be formulated with a pharmaceutically acceptable carrier to form a dosage form appropriate for each route of administration.

Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In these solid dosage forms, the active compound is mixed with at least one inert pharmaceutically acceptable carrier such as sucrose, lactose or starch. These dosage forms may also include, as is common practice, additional substances other than these inert diluents, e.g. lubricating agents such as magnesium stearate. In the case of capsules, tablets and pills, the dosage forms may also include buffering agents. The tablets and pills may further be prepared with an enteric coating.

Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups, elixirs containing inert diluents commonly used in the art, such as water. In addition to these inert diluents, the preparations may also include adjuvants such as wetting agents, emulsifying and suspending agents, and sweetening, perfuming and flavoring agents.

The formulations of the present invention for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions or emulsions. Examples of non-aqueous solvents or vehicles are propylene glycol, polyethylene glycol, vegetable oils such as olive oil and corn oil, gelatin and injectable organic esters such as ethyl oleate. These dosage forms may also contain adjuvants such as preservatives, wetting agents, emulsifying and dispersing agents. They may be sterilized by, for example, filtration through a bacteria-retaining filter, by introducing sterilizing agents, by introducing an agent into the formulation, by irradiating the formulation or by heating the formulation. They may also be manufactured in the form of a sterile solid which may be dissolved in sterile water or some other sterile injectable medium before use.

Preparations for rectal or vaginal administration are preferably suppositories, which may contain, in addition to the active substance, excipients such as cocoa butter or suppository wax.

Formulations for nasal or sublingual administration are prepared with standard excipients known in the art.

In addition, the compounds of the present invention can be administered in sustained release formulations, such as those described in the following patents. U. S. Patent No. 5,672,659 describes sustained release formulations comprising a bioactive agent and a polyester, U. S. Patent No. 5,595,760 describes sustained release formulations comprising a bioactive agent in gel form. U. S. Application No. 08/929,383 filed September 9, 1997 describes sustained release polymeric formulations comprising a bioactive agent and chitosan. U. S. Application No. 08/740,778 filed November 1, 1996 describes sustained release formulations comprising a bioactive agent and a cyclodextrin. U. S. Application No. 09/015,394 filed January 29, 1998 describes absorbable sustained release formulations of a bioactive agent. The disclosures of all of the foregoing patents and applications are incorporated herein by reference.

The dosage of the active ingredient in the preparations of the present invention may vary, but it is essential that the amount of active ingredient is such that a suitable dosage form is achieved. The selected dosage depends on the desired therapeutic effect, the route of administration, and the duration of treatment. In general, dosage levels range from 0.0001 to 100 mg per kg of body weight per day for humans and other animals, e.g. mammals, to achieve the desired effect.

The preferred range is from 0.01 to 5.0 mg/kg body weight per day, which may be administered in a single dose or divided into several doses.

The compound of the present invention can be synthesized according to the following description and Scheme 1. In the first step, an amino acid, protected at the ot-amino group with Boc, Cbz or other suitable group, is converted to a carboxylate salt with an inorganic base, for example NaOH, KOH, K ₂ CO ₃ or most preferably Cs ₂ CO ₃ in a polar solvent such as H ₂ O, DMF, THF and the like. The solvent is removed in vacuo and the remaining salt is redissolved in a polar aprotic solvent such as DMF and the appropriate α-haloketone is added with stirring at a temperature of -20 °C to 100 °C, most preferably at room temperature. Stirring is continued for 10 minutes to 24 hours or until the ester formation is complete by TLC analysis, after which the solution is concentrated under vacuum at 0 °C to about 100 °C, most preferably at 40 °C to 70 °C. The intermediate is then redissolved in an aprotic organic solvent such as benzene, toluene or most preferably xylenes and a 5- to 100-fold or most preferably about 15-20-fold molar excess of NH ₄ OAc is added. The biphasic mixture is heated to reflux and the polar layer is removed over 1 to 4 hours using an azeotropic attachment to give crude intermediate A which can be used crude or purified by crystallization or column chromatography.

Scheme 1

X= e.g. CBZ, BOC

1. Cs2CO2/DMF/H2O

2. Br-CH(R ³ )CO(R ⁴ )

3. _NH4OAc

1. Deprotection or derivatization

2. Possible repeated protection

3. Possible derivatization

(B) (A)

1peptide synthesis in solution

2. cyclization and deprotection

In the second step, intermediate A is generated using catalytic hydrogenation or a strong acid such as HF, HCl, HBr or Tfa. The α-amino group can then be protected using a base-sensitive protecting group such as the Fmoc group using commercially available N-(9-fluorenylmethoxycarbonyloxy)succinimide and K ₂ CO ₃ , for example in acetonitrile and water. Alternatively, the N _a -Cbz protected imidazole nitrogen can be alkylated with a protecting carboxylic ester halide and the α-amino group deprotected using catalytic hydrogenation « · ··· · * ··· · · «· • « « » · ··· · 9 · · » « · · « • · · · · ·« to give Β' (V = H, W = -(CH ₂ ) _m CR ⁵ CO ₂ R', where R' represents an alkyl or benzyl ester). The imidazole nitrogen can be protected using commercially available triphenylmethyl chloride and a tertiary amine base such as 4-methylmorpholine, diisopropylethylamine or triethylamine to give an Fmoc-protected intermediate, which is then reacted on the α-amino group using a base such as TAEA to give intermediate Β (V = H, W = Trt). Alternatively, the N-deprotected imidazole Β” (V = H, W = H) can be used without further modification.

In the third step, intermediate Β, B' or B” is used as an anchoring group to continue the synthesis of the target peptide in solution phase. The anchoring group is thus dissolved in ethyl acetate at a concentration of about 50 to 200 mmol per liter and 1 to 5 molar equivalents, more preferably 1.1 to 1.5 molar equivalents of the N _and -Fmoc protected amino acid in the form of its activated ester, anhydride or acyl halide are added. The mixture is stirred with a second layer of a weak base such as aqueous Na ₂ CO ₃ or more preferably aqueous NaHCO ₃ until the reaction is complete. The aqueous layer is removed and about 1 to 10 ml/mmol or more preferably about 2 to 4 ml/mmol of TAEA or piperidine is added and the mixture is stirred for about 30 minutes. The solution is then washed with saturated NaCl solution (twice with about 30 ml/mmol) and then with 10% phosphate buffer solution. buffer adjusts the pH of the solution to 5.5 (three times with 10 ml/mmol). Subsequent cycles are performed in a similar manner to the first cycle. The final amino acid can be protected at the N-terminal with a Boc or Fmoc group.

In the fourth step, the N-terminal and C-terminal protecting groups are removed using aqueous base or strong acid and the resulting peptide intermediate can be cyclized using classical peptide coupling techniques as described in “The Practice of Peptide Synthesis”, Bodanszky and Bodanszky, Springer-Verlag, 1984. The peptide intermediate is dissolved in an aprotic solvent such as DMF and the solution is made basic by the addition of a tertiary amine base such as 4-methylmorpholine. The carboxyl part of the intermediate is activated by the addition of a 1 to 6-fold molar excess of a carbodiimide such as DCC or EDC and by the addition of e.g. 1-hydroxy benzotriazole. The mixture is stirred at 0 °C to 100 °C, most preferably at room temperature, until the reaction is complete.

In the final step, the protected peptide is deprotected using catalytic hydrogenation or strong acids such as HF, HCl, HBr or Tfa to give the final product C, where R ¹ to R ⁵ , a, b, Y, Z and n are as defined above for the compound of general formula I.

• ·· ·* · 00 0 000 0 0 000 « 000

0 0 · 0 000

0 0 · 0 0 ·

000 0000 00 000 00 000

Infusion mass spectra were measured on a Finnigan SSQ 7000 spectrometer equipped with an ESI (electrospray ionization) source. NMR data were obtained on a 300 MHz Varian Unity spectrometer on samples at concentrations from 10 to 20 mg/ml in the indicated solvents.

Alternatively, the compounds of the invention can be prepared using solid phase peptide synthesis techniques. Thus, intermediate A (X = Boc) is alkylated with, for example, ethyl bromoacetate and a suitable base such as K ₂ CO ₃ in an aprotic solvent such as DMF and the resulting ethyl ester intermediate is hydrolyzed using an aqueous base such as NaOH to give intermediate B (V = Boc, W = -CH ₂ CO ₂ H). Intermediate B (V = Boc, W = -CH ₂ CO ₂ H) can be activated using known activation techniques as described in "The Practice of Peptide Synthesis", Bodanszky and Bodanszky, Springer-Verlag, 1984, and can be used directly for coupling to a growing peptide on a solid support, or intermediate B (V = Boc, W = CH ₂ CO ₂ H) can be attached directly to a solid support to initiate solid phase synthesis. Deprotection of the n-terminal Boc group with, for example, Tfa, allows peptide synthesis to proceed under conditions known to those skilled in the art of peptide synthesis.

Intermediate B (V = Fmoc, W = -CH ₂ CO ₂ t-Bu e.g.) can be reacted with an acid e.g. Tfa to remove the protecting tert-butyl ester group and the resulting intermediate B (V = Fmoc, W = -CH ₂ CO ₂ H e.g.) can be used for solid phase peptide synthesis using Fmoc. Intermediate B (V = Fmoc, W = -CH ₂ CO ₂ H e.g.) can be activated using known activation techniques as described in “The Practice of Peptide Synthesis”, M. Bodanszky and A. Bodanszky, Springer-Verlag, 1984 and can be used directly for coupling to the growing peptide on a solid support. Deprotection of the N-terminal Fmoc group with e.g. piperidine allows the peptide synthesis to continue under conditions known to those skilled in the art.

Solid-state synthesis of cyclic analogs can also be carried out according to Scheme II below.

SCHEME II

E-

ν# — \

O- resin (F)

R' = alkyl, benzyl R* = Boc, Fmoc

Intermediate A (X = Boc or Cbz, R ³ = 2-methoxyphenyl, 3-methoxyphenyl or 4-methoxyphenyl) can be reacted with 1 M BBr3 in CH2Cl2 for 0.5 h to give the free phenol A (X = H, R ³ = 2-hydroxyphenyl, 3-hydroxyphenyl or 4-hydroxyphenyl). The α-Nitrogen can be protected with an acid-labile protecting group such as Boc using di-tert-butyldicarbonate and a base such as NaOH in a mixture of an organic water-miscible solvent such as dioxane and water. Intermediate A (X = Boc, R ³ = 2-hydroxyphenyl, 3-hydroxyphenyl and 4-hydroxyphenyl) is alkylated with ethyl bromoacetate and a suitable base such as K2CO ₃ in an aprotic solvent such as DMF to give the ethyl ester intermediate D. Intermediate D is then converted to the cesium salt by treatment with cesium carbonate. The cesium salt is reacted in excess with Merrifield resin to give intermediate E. Intermediate E is then worked up using standard solid phase Boc synthesis or standard solid phase Fmoc synthesis as described above.

9 9 9 9 9 9 9 • 99 9999 99 ··· «9 999 described previously to give intermediates F. Once the complete amino acid sequence is constructed, the C-terminus is unmasked using a suitable base such as LiOH in aqueous DMF and the peptide is cyclized using a standard activation protocol, e.g. carbodiimide with hydroxybenzotriazole and a tertiary base such as diisopropylethylamine to give intermediates G. Final side chain deprotection and cleavage from the resin is accomplished by addition of a very strong acid such as HF to give the compounds of the present invention.

This invention is further illustrated by means of examples, which are not intended to be limiting.

Examples of embodiments of the invention

Example 1 cyclo[Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Glyj

Example 1 was synthesized according to synthetic scheme 1 as shown below:

*

0«

3. _NH4OAc

4. 6N HCl

1. CSjCOj/DMF/Η,Ο

2. Br-CH(R«)CO-R ³

Fmoc-OSu/K,CO ₃ CHjCN/HjO ·»

R·

FmocN

R 'VVk

H

Trityl-Cl/NMM

CH,Cl, (b)

Solution synthesis

R'

Fmoc-ÍZVX^X^-X^YVN^^ (d)

R N Trt

1. Tfa/iPr ₃ SiH

2. Br-(CH ₂ )_CHR ⁵ CO ₂ Et/KHCO/DMF

1. TAEA/EtOAc

2. NaOH/H2O/MeOH

3. EDC/HOBt/DMF

HYPd on carbon HOAc

O

(G)

About (f)

Step a: 2-(1-(S)-amino-2-phenylethyl)-4-(3-methoxyphenyl)imidazole

Cbz-(L)-Phenylalanine (10.0 g, 33.4 mmol) and Cs ₂ CO ₃ (5.44 g, 16.7 mmol) were mixed with a 2:1 mixture of DMF:water (75 ml) and the mixture was stirred until homogenous. The solvent was removed under reduced pressure, the residue was dissolved in DMF (70 ml) and 7.65 g of 2bromo-3'-methoxyacetophenone (33.4 mmol) in 30 ml of DMF was added. The mixture was stirred for 30 min at room temperature and then concentrated under reduced pressure. The resulting ketoester was dissolved ·· *· · ·· · • · ♦ ♦ ·· < · ·· φφφφ φ φ · • •φφ φ·»· >

φ φφφ φφ· φφφ φφφφ φφ _φ in xylene (150 mL) and the CsBr was filtered off. Ammonium acetate (40.0 g, 0.52 mol) was then added and the mixture was heated to reflux for 2 h with removal of excess AcONH ₄ and the resulting water using an azeotropic attachment. The reaction was cooled and washed with saturated NaHCO ₃ solution (50 mL) and then saturated NaCl solution (50 mL). The xylene layer was dried over Na ₂ SO ₄ , filtered and concentrated in vacuo.

The residue was dissolved in 30 mL of dioxane, 6N HCl (115 mL) was added, and the mixture was heated to reflux for about 3 h. The solution was concentrated under reduced pressure and triturated with diethyl ether (4 x 100 mL). The residue was dried under vacuum to constant weight to give 12.15 g (99%) of intermediate 1a, mass spectrum 294.2 MH ⁺ .

Step b: 2-(1-(S)-((Fluorenylmethoxy)carbonyl)amino-2-phenylethyl)-4-(3-methoxyphenyl)imidazole

Intermediate 1a (11.8 g, 32.2 mmol) was dissolved in 200 mL _of acetonitrile:water (1:1) and then _K2CO3 (5.38 g, 39 mmol) was added carefully in portions. 9-Fluorenylmethylsuccinimidylcarbonate was then added and the resulting mixture was stirred vigorously for 20 min. The product was extracted with ethyl acetate (100 mL) and the ethyl acetate layer was washed with water (2 x 50 mL). The ethyl acetate layer was dried over _Na2SO4 , _filtered and concentrated in vacuo. The product was purified by flash chromatography on silica gel (150 g) with an eluent of 2:2:1/ _CH2Cl2 : _hexane :EtOAc and then 1:1/hexane:EtOAc. The product fractions were combined and concentrated in vacuo to give intermediate 1b as a pale yellow foam, 14.77 g (85%). Mass spectrum 516.3 MH ⁺ , NMR (300 MHz, DMSO-d ₆ ), 11.8-12.0 (1H, s), 7.8-8.0 (3H, d), 7.6-7.8 (2H, d), 7.5 (1H, s), 7.1-7.5 (12H, m), 6.7-6.9 (1H, d), 4.8-5.0 (1H, m), 4.1-4.3 (3H, m), 3.7-3.9 (3H, s), 3.0-3.4 (2H, m).

Step c: 2-(1-(S)-((Fluorenylmethoxy)carbonyl)amino-2-phenylethyl)-4-(3-methoxyphenyl)-1triphenylmethylimidazole

Intermediate lb (13.9 g, 26.9 mmol) was dissolved in 50 mL of CH ₂ Cl ₂ under N ₂ , then 4-methylmorpholine (2.96 mL, 26.9 mmol) and chlorotriphenylmethane (7.51 g, 26.9 mmol) were added and the solution was stirred at room temperature for 45 min. The solids were removed by filtration and the filtrate was purified by flash chromatography on silica gel (300 g) using 70:30/hexane:EtOAc as eluent. The product-containing fractions were combined and concentrated in vacuo to give intermediate 1c as a foam, 18.0 g (88%), NMR (300 MHz, DMSO-d ₆ ), 7.84-7.95 (2H, d),

7.7-7.8 (IH, d), 7.6-7.7 (IH, d), 6.7-7.5 (29H, m), 4.3-4.5 (IH, m), 3.75-3.95 (2H, m), 3.75-3.85 (3H, s), 3.6-3.7 (IH, m), 2.65-2.85 (IH, dd), 2.05-2.2 (1H, m).

Step d: 2-(1-(S)-((Fmoc-Tyr(OBzl)-D-Trp-Lys(Cbz)-Val)amino-2-phenylethyl)-4-(3-methoxyphenyl)-1-(triphenylmethyl)imidazole

Intermediate 1c (1.89 g, 2.50 mmol) was dissolved in 40 mL of ethyl acetate, then 9 mL of tris(2-aminoethyl)amine was added and the mixture was stirred vigorously for about 30 min. The ethyl acetate layer was washed with saturated NaCl solution (2 x 120 mL) and then the pH was adjusted with 10% phosphate buffer to pH = 5.5 (3 x 40 mL). The ethyl acetate layer was stirred overnight with saturated NaHCO ₃ solution (40 mL) and Fmoc-Val-F (1.02 g, 3.00 mmol) was added. The reaction mixture was stirred for 1 h and the aqueous layer was removed.

The intermediate was then sequentially deprotected and coupled with Fmoc-Lys(Cbz)-Osu, Fmoc-DTrp-Osu and Fmoc-Tyr(OBzl)-Osu in a similar manner as described above for the Fmoc-Val-F cycle. The ethyl acetate layer was diluted with 1.5 volumes of hexane and applied to a silica gel column for purification by flash chromatography using first 50:30:20/CH ₂ Cl ₂ :EtOAc:hexane and then 4:1/EtOAc:hexane as eluent. The product fractions were combined and concentrated in vacuo to give intermediate 1d as a white foam, 1.90 g (46%). Mass spectroscopy 1581.2 MNa ⁺ , 1559.5 MH ⁺ .

Step e: 1-((2-Ethoxy-2-oxo)ethyl)-2-(1-(S)-((Fmoc-Tyr(OBzl)-D-Trp-Lys(Cbz)-Val)amino-2-phenylethyl)-4-(3-methoxyphenyl)imidazole

Intermediate ld (519 mg, 0.33 mmol) was dissolved in 10 mL of Tfa containing i-Pr ₃ SiH (205 µL, 1.0 mmol) and the mixture was stirred for 15 min. The intermediate was precipitated by addition of diethyl ether (60 mL) and filtered. Mass spectroscopy: 1316 MH ⁺ . The intermediate was dissolved in 3 mL of DMF, then KHCO ₃ (198 mg, 2.0 mmol) and ethyl bromoacetate (721 µL, 6.5 mmol) were added and the mixture was stirred overnight at room temperature. The mixture was concentrated in vacuo, dissolved in 10 mL of CH ₂ Cl ₂ and washed with 10 mL of water. The dichloromethane layer was dried over Na ₂ SO ₄ , filtered and concentrated in vacuo to give crude intermediate 1e (540 mg) which was used without further purification.

Step f: cyclo[Tyr(OBzl)-D-Trp-Lys(Cbz)-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Glyj

Intermediate 1e (540 mg, 0.33 mmol) was suspended in 10 ml ethyl acetate, 1 ml tris(aminoethyl)amine was added and the mixture was stirred vigorously for 30 min. Ethyl acetate (10 ml) was then added and the solution was washed with saturated NaCl solution (2 x 25 ml) and then the pH was adjusted to 5.5 with 10% phosphate buffer (3 x 10 ml). The intermediate was precipitated by addition of hexane (40 ml) and the solution was decanted. The residue was dissolved in 10 ml methanol and stirred overnight at room temperature with 2.5 N NaOH (0.5 ml). The mixture was diluted until cloudy with water and the pH was adjusted to pH = 6.7. The deprotected intermediate was filtered off and dried in vacuo. The solid was dissolved in DMF (25 mL) and DCC (340 mg, 1.65 mmol) and HOBt (252 mg, 1.65 mmol) were added. The mixture was stirred for 2 h at room temperature and then concentrated under reduced pressure. The crude product was purified by flash chromatography on silica gel using AcOEt as eluent. The product-containing fractions were combined and concentrated in vacuo to give intermediate 1f as a glass (180 mg, 48% from intermediate 1d). Mass spectroscopy:

1134.5 MH ⁺ .

Step g: cyclo[Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Intermediate 1f (180 mg, 0.16 mmol) was dissolved in 10 mL of acetic acid containing

10% palladium on carbon (24 mg) and the mixture was shaken under H ₂ (25 psi) at room temperature for 8 h. The catalyst was then filtered off and the residue concentrated in vacuo. The crude mixture consisted of completely deprotected material (both CBz and benzyl ethers removed) and partially deprotected material (Cbz decitrated, benzyl ether remaining). The mixture was purified by preparative HPLC on a VYDAC® Protein & Peptide C _]8 column (The Nest Group Inc., Southborough, MA) using a gradient of 20% to 70% CH ₃ CN/0.1% Tfa over 55 min. The 4 pure fractions of the more polar peak were combined, concentrated and lyophilized (2 x 10 mL 0.5% HCl, then 1 x 10 mL water) to give the title compound of Example 1 (1.45 mg, 29%). Mass spectrometry: 910.4 MH ⁺ .

Example 2 cyclo[Tyr(OBzl)-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 2 was prepared according to synthetic scheme 1 in Example 1, but using the appropriate amino acids. The pure fractions of the less polar peak from the purification of 1 g of material were combined, concentrated and lyophilized (2 x 10 mL 0.5% HCl, then 1 x 10 mL water) to give the product of Example 2, 33 mg (21%). Mass spectroscopy: 1000.4 MH ⁺ .

AA ·· · AA A • A · ·· AAAA • · · · A A A • AAA AAAA A

A AAA AAA

AAA AAA AAA AAA

Example 3 cyclo[Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 3 was prepared according to synthetic scheme 1 in Example 1, but with the following differences:

Step d: 2-(1-(S)-((Fmoc-Trp-D-Trp-Lys(Cbz)-Val)amino-2-phenylethyl)-4-(3-methoxyphenyl)-1-(triphenylmethyl)imidazole

Intermediate 1c (757 mg, 1.0 mmol) was dissolved in 20 mL AcOEt, then tris(2-aminoethylamine) (3 mL) was added and the mixture was stirred vigorously for half an hour. The ethyl acetate layer was washed with saturated NaCl solution (2 x 60 mL) and then the pH of the mixture was adjusted to 5.5 with 10% phosphate buffer (3 x 20 mL). The ethyl acetate layer was stirred overnight with saturated NaHCO ₃ solution (20 mL) and Fmoc-Val-F (825 mg, 2.33 mmol) was added. The reaction was stirred for 1 h and the aqueous phase was removed.

The intermediate was successively deprotected and coupled with Fmoc-Lys(Cbz)-OSu, Fmoc-D-TrpOSu and Fmoc-Trp-OSu in a similar manner as described for the Fmoc-Val-F cycle. The ethyl acetate layer was diluted with 1.5 volumes of hexane and subjected to column chromatography using first 50:30:20/CH ₂ Cl ₂ :EtOAc:hexane and then 4:1/EtOAc as eluent. The product-containing fractions were combined and concentrated under reduced pressure to give intermediate 3d as a white foam, 1.02 g, (68%). Mass spectroscopy: 11492.0 (MNa ⁺ ), 1514.2 (MH ⁺ ).

Step e: 1-((2-Ethoxy-2-oxo)ethyl)-2-(1-(S)-((Fmoc-Trp-D-Trp-Lys(Cbz)-Val)amino-2-phenylethyl)-4-(3-methoxyphenyl)-1-(triphenymethylimidazole)

Intermediate 3d (1.00 g, 0.67 mmol) was dissolved in a mixture of CH ₂ Cl ₂ (10 mL), Tfa (1 mL) and i-Pr ₃ SiH (205 μΐ, 1.0 mmol) and the mixture was stirred for 20 min. A mixture of 1:1/Et ₂ O:hexane (100 mL) was added and the intermediate was filtered off and dried (0.88 g). The intermediate was dissolved in 10 mL DMF, then KHCO ₃ (200 mg, 2.00 mmol) and ethyl bromoacetate were added and the reaction mixture was stirred overnight at room temperature. The mixture was then concentrated under reduced pressure to give intermediate 3e, which was used without further purification. Mass spectrometry: 1335.7 MH ⁺ .

Step f: cyclo[Trp-D-Trp-Lys(Cbz)-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Intermediate 3e (crude, 0.67 mmol) was dissolved in 10 mL of methanol and stirred for 45 min at room temperature with 2.5 N NaOH (1.0 mL). The mixture was diluted with water until cloudy and the pH was adjusted to 6.9. The solvent was decanted and the residue was triturated with water to give a light yellow powder (650 mg, mass spectrometry: 1085.5 MH ⁺ ). The powder (629 mg) was dissolved in 20 mL DMF, NMM (220 μΐ, 2.0 mmol), EDC (192 mg, 1.0 mmol) and HOBt (153 mg, 1.0 mmol) were added. The mixture was stirred at room temperature for 2 h and then concentrated in vacuo. The crude product was dissolved in 15 mL CH2Cl2 and washed with 10% phosphate buffer ^- (adjusted to pH = 5.5). The dichloromethane layer was dried over _Na2SO4 , filtered and concentrated to 2 mL. Ethyl ether was then added to precipitate the product, which was filtered off and dried to give intermediate 3f (440 mg, 71%). Mass spectrum: 1067.4 MH ⁺ .

Step g: cyclo[Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Intermediate 3f (200 mg, 0.19 mmol) was dissolved in 15 mL of acetic acid containing

10% palladium on carbon (40 mg) and the mixture was shaken under a hydrogen atmosphere (25 psi) for 2 days at room temperature. The catalyst was then filtered off and the residue was concentrated in vacuo. The crude mixture was purified using preparative HPLC on a C ₁₈ column (Rainin Microsorb™ 80220-C5) using a gradient of 20% to 70% CH ₃ CN/0.1% Tfa over 55 minutes. A second pass using a gradient of 30% to 50% CH ₃ CN/0.1% Tfa over 55 minutes was required to obtain good separation. The pure fractions were combined, concentrated and lyophilized (2 x 10 mL 0.5% HCl, then 1 x 10 mL water) to give the title compound of Example 3, 26 mg, (14%). Mass spectroscopy: 933.5 MH ⁺ .

Example 4:

cyclo[Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly]

Example 4 was prepared according to synthetic scheme 1 similarly to that described in Example 1 with the following differences:

Step g: cyclo[Trp-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly]

Intermediate 3f (150 mg, 0.14 mmol) was dissolved in 12 mL of CH ₂ Cl ₂ and a solution of BBr ₃ in hexane under nitrogen. The resulting slurry was stirred for 0.5 h. Methanol (10 mL) was then added and the mixture was concentrated in vacuo. The crude mixture was purified by preparative HPLC on a C _1g column using a gradient from 24% to 48% CH ₃ CN/0.2/ NH ₄ OAc over 50 min. The pure fractions were combined, concentrated and lyophilized (2 x 10 mL water) to give the title compound of Example 4, 40 mg (29%). Mass spectroscopy: 919.4 MH ⁺ .

Example 5 • «0 00 0 »0 0 ·· · · 0 · 00 0 0 00 • 0 0*0 0 0 0 • · 0 · · 0 0·· 0 •0 000 000 • 0 0000 00 00 00· cyclo[Trp-D-Trp-Lys-Thr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Glyj

Example 5 was prepared according to Scheme 1 in a similar manner to that described for Example 3 except that Fmoc-Thr(OBzl)-F was used instead of Fmoc-Val-F in step d. Mass spectrometry: 1025.5 MH ⁺ .

Example 6 cyclo[Trp-D-Trp-Lys-Thr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly]

Example 6 was prepared according to Scheme 1 in a similar manner to that described for Example 4 except that intermediate 5f, cyclo[Trp-D-Trp-Lys(Cbz)-Thr(Obzyl)-Phe Ψ (4-(3methoxyphenyl)imidazole)-Gly] was used instead of intermediate 3f in step g. Mass spectroscopy: 1025.5 MH ⁺ .

Example 7 cyclo[Trp-D-Trp-Lys-Thr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 7 was prepared according to Scheme 1 in a similar manner to that described for Example 3 except that Fmoc-Abu-F was used instead of Fmoc-Val-F in step d and the carbodiimide and HoBt cyclization in step 3f was not performed. Mass spectrometry: 937.3 MH ⁺ .

Example 8 cyclo[Trp-D-Trp-Lys-Thr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 8 was prepared according to Scheme 1 in a similar manner to that described for Example 3 except that Fmoc-Abu-F was used instead of Fmoc-Val-F in step d. Mass spectrometry: 919.5 MH ⁺ .

Example 9 cyclo[Phe-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(1,1-dimethylethyl)imidazole)-Gly]

Example 9 was prepared according to Scheme 2.

• ·· • · · fl fl ♦ ·· • ·« • • fl • • « fl • fl • • • fl • • • · • • • • fl • • flfl flflfl* • fl flflfl • · • flfl

SCHEME 2

BocNH

Ø' ,ν*

solution synthesis

R*

Fmoc-(Z) _n -X'

(h)

R

Br(CH ₂ ) _OT CHR ⁵ CO ₃ Et/

_KHCO3 /DMF

Step a: 2-(1-(S)-amino-2-phenylethyl)-4-(1,1-dimethylethyl)imidazole

Boc-(L)-phenylalanine (5.31 g, 20.0 mmol) and Cs ₂ CO ₃ (3.26 g, 10.0 mmol) were mixed in a 1:1/DMF;H ₂ O (50 mL) mixture and stirred until a homogeneous mixture was obtained. The solvent was removed under reduced pressure and the residue was dissolved in 50 mL DMF and 1-chloropinacolone (2.63 mL, 20.0 mmol) was added. The mixture was stirred overnight at room temperature and then concentrated under reduced pressure. The resulting ketoester was dissolved in 100 mL xylene and the CsBr was filtered off. Ammonium acetate (25.0 g, 0.33 mol) was then added and the mixture was

• ·· ·· • 99 • · 9 9 9 • 9 9 9 99 • 9 9 · • 9 9 • · * • • • • 9 9 • 9 • 9 9 t 9 99 9999 99 999 99 99

heated to reflux for 2 h while removing excess AcONH ₄ and the liberated water using an azeotropic attachment. The reaction was cooled and washed with saturated NaHCO 4 solution (50 mL), dried over Na ₂ SO ₄ , filtered and concentrated in vacuo. Purification of the protected intermediate was carried out by flash chromatography on silica gel using 80:20/hexane:EtOAc as eluent to give 3.45 g (50%) of a crystalline intermediate (Mass spectrometry: 344.3 MH ⁺ ). This intermediate was dissolved in 30 mL of methanol and concentrated sulfuric acid (5.0 mL) was added and the mixture was stirred for about 3 h. The solution was concentrated in vacuo and the residue was precipitated from THF and diethyl ether. The solid was dried under vacuum to give 1.89 g (95%) of intermediate 9a. NMR (300 MHz, DMSO-d ₆ ), 8.5-10.5 (3H, broad s), 7.3-7.4 (1H, s), 7.15-7.35 (3H, m), 7.0-7.1 (2H, m), 4.9-5.1 (1H, t), 3.5-3.65 (2H, d), 1.2-1.3 (9H, s).

Step h: 2-(1-(S)-((Fmoc-Phe-D-Trp-Lys(Boc)-Tyr(Obzl))-amino-2-phenylethyl)-4-(1,1-dimethylethyl)-1H-imidazole

Intermediate 9a (790 mg, 2.50 mmol) was dissolved in 40 mL AcOEt, tris(2-aminoethyl)amine (9 mL) was added and the mixture was stirred vigorously for 0.5 h. The ethyl acetate layer was washed with saturated NaCl solution (2 x 120 mL) and then with 10% phosphate buffer adjusted to pH = 5.5 (3 x 40 mL). The ethyl acetate layer was stirred with saturated NaHCO ₃ solution (40 mL) and FmocTyr(OBzl)-OSu (1.02 g, 3.00 mmol) was added. The reaction was stirred for 1.5 h and the aqueous layer was removed.

The intermediate was successively deprotected and coupled with Fmoc-Lys(Cbz)-OSu, Fmoc-D-TrpOSu and Fmoc-Phe-OSu in a similar manner as described above for the Fmoc-Tyr(OBzl)-OSu cycle. The ethyl acetate layer was applied to a silica gel column for purification by flash chromatography using 1% acetic acid/EtOAc as eluent. The product-containing fractions were combined and concentrated in vacuo. The crude product was dissolved in AcOEt, precipitated by addition of hexane and filtered. The solid was dried in vacuo to give intermediate 9h, 1.67 g (52%). Mass spectroscopy: 1280.7 MH ⁺ .

Step e: 4-(1,1-dimethylethyl)-2-(1-(S)-((Fmoc-Phe-D-Trp-Lys(Boc)-Tyr(Obzl))-amino-2-phenylethyl)-1-(2-ethoxy-2-oxoethyl)imidazole

Intermediate 9h (128 mg, 0.10 mmol) was dissolved in 2 mL DMF, _{K2CO3 (} 35 mg, 0.25 mmol) and ethyl bromoacetate (28 µL, 0.25 mmol) were added and the mixture was stirred overnight at room temperature. The mixture was concentrated in vacuo, dissolved in 10 mL AcOEt and washed with water (10 mL). The ethyl acetate layer was dried _{over Na2SO4 ,} filtered and concentrated in vacuo to give crude intermediate 9e (126 mg, 92%), which was used without further purification.

Step f: cyclo[Phe-D-Trp-Lys(Boc)-Tyr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Intermediate 9e (116 mg, 0.085 mmol) was suspended in 2 mL AcOEt and tris(aminoethyl)amine (0.5 mL) was added and the mixture was stirred vigorously for 0.5 h. Ethyl acetate (10 mL) was then added and the solution was washed with saturated NaCl solution (2x5 mL) and then with 10% phosphate buffer solution (pH = 5.5, 3x5 mL). The intermediate was precipitated by adding 40 mL hexane and the intermediate was filtered off (76 mg). The residue was dissolved in 2 mL methanol and stirred overnight at room temperature with 2.5 N NaOH (0.1 mL). The mixture was diluted until cloudy with water and the pH was adjusted to 6.0. The deprotected intermediate was filtered off and dried in vacuo. The solid was dissolved in DMF (20 mL) and DCC (126 mg, 0.60 mmol) and HOBt (90 mg, 0.60 mmol) were added. The mixture was stirred for 6 h at room temperature and then concentrated in vacuo. It was then dissolved in 5 mL of EtOAc and washed with saturated NaHCO ₃ solution (1x5 mL) and saturated NaCl solution (5 mL). The mixture was dried over Na ₂ SO ₄ , filtered and concentrated in vacuo to give intermediate 9f. Mass spectroscopy: 1098.5 MH ⁺ .

Step g: cyclo[Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(1,1-dimethylethyl)imidazole)-Gly]

Intermediate 9f (crude, 0.085 mmol) was dissolved in Tfa (9.4 mL) containing i-Pr ₃ SiH and water (0.5 mL), stirred for 20 min, and then concentrated in vacuo. The crude mixture was purified by preparative HPLC on a C ₁₈ column using a gradient of 30% to 60% CH ₃ CN/0.1% Tfa over 50 min. A second pass using a gradient of 32% to 80% CH ₃ CN/0.2% NH ₄ OAc over 50 min was required for good separation. The pure fractions were combined, concentrated, and lyophilized (2 x 10 mL 0.5% HCl, then 1 x 10 mL water) to give the title compound of Example 9, 9 mg (10%). Mass spectroscopy: 998.4 MH ⁺ .

Example 10 cyclo [Phe-D-Trp-Lys-Val-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 10 was prepared according to Scheme 1 in a similar manner to Example 3 except that Fmoc-Phe-Osu was used instead of Fmoc-Trp-F in step d. Mass spectroscopy: 894.4 MH ⁺ .

Example 11 cyclo [Phe-D-Trp-Lys-Tyr(OBzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly] • ·· ·· · *« * ··· · b ··· · · · · · · • · · · · · · · · · · · · * · · · · · · · · · · · · · · · · ·» ·· ··· Example 11 was prepared according to Scheme 1 in a similar manner to that described in Example 3 except that Fmoc-Phe-OH was used instead of Fmoc-Trp-F and FmocTyr(OBzl)-OH was used instead of Fmoc-Val-F in step d. Fmoc-Tyr(OBzl)-OH was activated with DCC and commercially available HOAt. The crude mixture in step g consisted of fully deprotected material (both Cbz and benzyl ether were removed) and partially deprotected material (Cbz was removed, benzyl ether remained). The less polar peak resulting from partial deprotection gave the title compound of Example 11. Mass spectroscopy: 1048.5 MH ⁺ .

Example 12 cyclo[Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 12 was prepared according to Scheme 1 in a similar manner to that described in Example 3 except that Fmoc-Phe-OH was used instead of Fmoc-Trp-F and FmocTyr(OBzl)-OH was used instead of Fmoc-Val-F in step d. Fmoc-Tyr(OBzl)-OH was activated with DCC and commercially available HOAt. The crude mixture in step g consisted of fully deprotected material (both Cbz and benzyl ether were removed) and partially deprotected material (Cbz was removed, benzyl ether remained). The more polar peak resulting from partial deprotection gave the title compound of Example 12. Mass spectroscopy: 958.4 MH ⁺ .

Example 13 cyclo[Phe-D-Trp-Lys-Tyr-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Glyj

Example 13 was prepared according to Scheme 1 in a similar manner to that described in Example 4 except that intermediate llf, cyclo[Phe-D-Trp-Lys(Cbz)-Tyr(OBzl)-Phe Ψ (4-(3methoxyphenyl)imidazole)-Gly] was used instead of intermediate 3f in step g. Mass spectrometry: 944.6 MH ⁺ .

Example 14 cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 14 was prepared according to Scheme 2 in a similar manner as described in Example 9 with the following differences:

Step h: 2-(1-(S)-((Fmoc-Trp-D-Trp-Lys(Cbz)-Tyr(Bzl))-amino-2-phenylethyl)-4-(3methoxy phenyl)-1 -(triphenylmethyl)imidazole ·· ··· ··

Peptide synthesis was performed in a similar manner to step 9h except that Fmoc-Trp-OSu was used instead of Fmoc-Phe-OSu, Fmoc-Lys(Boc)-OSu was used instead of Fmoc-Lys(Cbz)-OSu, and Fmoc-Tyr(Bzl)-OSu was used instead of Fmoc-Val-OSu. Yield = 783 mg (57%). Mass spectroscopy: 1370.6 MH ⁺ .

Step e: 1 -((2-Ethoxy-2-oxo)ethyl)-2-(1-(S)-((Fmoc-Trp-D-Trp-Lys(Boc)-Tyr(OBzl))-amino-2-phenylethyl)-4-(3-methoxyphenyl)-imidazole

Alkylation of intermediate 14h was carried out in a similar manner as in reaction 9h, yield = 640 mg (80%), mass spectroscopy: 1456.3 MH ⁺ .

Step f: cyclo[Trp-D-Trp-Lys(Boc)-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Intermediate 14e (640 mg, 0.44 mmol) was dissolved in 15 mL of methanol and 2.5N NaOH (1 mL, 2.5 mmol) was added. The mixture was stirred for 0.5 h and then the pH was adjusted to 7.0 with 5% HCl solution. The methanol was removed under reduced pressure and the aqueous layer was decanted. The residue was dried well under reduced pressure and then dissolved in 15 mL of DMF. DCC (206 mg, 1.0 mmol) and HOBt (153 mg, 1.0 mmol) were added and the mixture was allowed to stir overnight. The reaction was concentrated in vacuo, dissolved in 10 mL of AcOEt and washed twice with 10% phosphate buffer solution, pH = 5.5. The ethyl acetate layer was applied to a silica gel column and the product was eluted with ethyl acetate. The product-containing fractions were combined and concentrated to give 240 mg (46%) of intermediate 14f.

Step g: cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Intermediate 14f (240 mg, 0.20 mmol) was dissolved in 10 mL of CH ₂ Cl ₂ and Tfa (10 mL) containing i-Pr ₃ SiH (205 μΐ, 1.0 mmol) was added. The mixture was stirred for 15 min at room temperature. The dichloromethane layer was evaporated under reduced pressure and the crude product was precipitated by addition of ether. The solvents were decanted and the residue was further purified by preparative HPLC on a C ₁₈ column using a gradient of 30% to 50% CH ₃ CN/0.1% Tfa over 55 min. The pure fractions were combined, concentrated and lyophilized (1 x 10 mL 0.5% HCl, then 1 x 10 mL water) to give the title compound of Example 14, 25 mg (11%). Mass spectroscopy: 1087.4 MH ⁺ .

Example 15 cyclo[Tyr-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly]

Example 15 was prepared according to synthetic scheme 1 in a similar manner to Example 4 with the following exceptions:

• 99·· · » * • · · · · · · · · * ·· · · · · 9' · ··· ···>» ·· ··· ··· ···

Intermediate 1f (130 mg, 0.115 mmol) was dissolved in 5 mL of dichloromethane and 1M BBr ₃ in hexane (5 mL) was added under N ₂ . The resulting slurry was stirred for 0.5 h and then cooled to 0 °C. Methanol (10 mL) was then added and the mixture was concentrated in vacuo. The crude mixture was applied to a C ₁₈ column, washed with 1% NH ₄ OAc, washed with 0.1% Tfa and then eluted with a gradient of 20% to 35% CH ₃ CN/0.1% Tfa over 50 min. The pure fractions were combined, concentrated and lyophilized (2 x 10 mL 0.5% HCl) to give the title compound of Example 15, 60 mg (54%). Mass spectroscopy: 896 MH ⁺ .

Example 16 cyclo[Phe-D-Trp-Lys-Nal-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly]

Example 16 was prepared according to Scheme 1 in a similar manner as described in Example 3 with the following exceptions:

Step d: 2-( 1 -(S)-((Fmoc-Phe-D-Trp-Lys(Cbz)-Nal)-amino)-2-phenylethyl)-4-(3-methoxyphenyl)-1-(triphenylmethyl)-imidazole

Intermediate 16d was prepared similarly to intermediate 1d except that Fmoc-Nal-OAt was used instead of Fmoc-Val-F and Fmoc-Phe-OH was used instead of Fmoc-Tyr(Bzl)-OH.

Step g: cyclo[Phe-D-Trp-Lys-Val-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-Gly]

Step 16g was performed in a similar manner to step 4g to give the title compound of Example 16.

Example 17 cyclo[Phe-D-Trp-Lys-Nal-Phe Ψ (4-(3-methoxyphenyl)imidazole)-Gly]

Example 17 was prepared according to the schemes in a similar manner as described for the analogous Example 16 with the following exceptions:

Intermediate 17f (310 mg, 0.27 mmol) was suspended in 3 mL of anisole and 12 mL of anhydrous HF was added. The mixture was stirred for 1 h at 0 °C. The HF was distilled off and the product was precipitated by addition of ether. The crude product was filtered off and further purified by preparative HPLC using a gradient of 20 to 80% CH ₃ CN/0.1% Tfa over 40 min. The pure fractions were combined, concentrated and lyophilized with twice diluted HCl. Yield = 56 mg (19%). Mass spectrometry: 992.4 MH ⁺ .

Scheme 3

HN'

R' JU ω fe*

IN

3. NH ₄ OAc synthesis in solution ► φ φ φφφ φφφ · φ · · *··< ·* φ

1. CSjCOj/DMF/HjO

2. Br-CH(R ⁴ )CO-R ³

(and)

1. Br-(CH(R ⁵ )CO,tBu/KaCQj/DMF

2. H/PdonC

R*

Βοο-ίΖ^-Χ'-χΤχίχ^χ.Ν ''>A_- _R ³ (k)

Ø' kJ ^R<

R'

R'

O

1. EDCZHOBt/DMF

3.Tfa/iPr,SiH -Χ'-Χ’-Χ^Υ),

0) <V;

R N/

HIM

O

strong acid H-j/Pd on carbon HÓAc

Example 18 cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-(γ)Abu]

Example 18 was prepared according to synthetic scheme 3.

Step i: 2-(1-(S)-((Phenylmethoxy)carbonyl)-amino-2-phenylethyl)-4-(4-methoxyphenyl)imidazole

Cbz-(L)-Phenylalanine (10.0 g, 33.4 mmol) and Cs ₂ CO ₃ (5.44 g, 16.7 mmol) were mixed in a 2:1/DMF:water (75 mL) mixture and stirred until a homogeneous mixture was obtained. The solvent was removed under reduced pressure and the residue was dissolved in 70 mL DMF and 243 bromo-3'-methoxy acetophenone (7.65 g, 33.4 mmol) in 30 mL DMF was added. The mixture was stirred for 0.5 h at room temperature and then concentrated under reduced pressure. The resulting ketoester was dissolved in 150 mL xylene and the CsBr was filtered off. Ammonium acetate (40.0 g, 0.52 mol) was then added and the mixture was heated to reflux for 2 h while removing excess ammonium acetate and evolved water using an azeotropic addition. The reaction was cooled and washed with saturated NaHCO ₃ solution (50 mL) and saturated NaCl solution (50 mL). The xylene layer was dried over Na ₂ SO ₄ , filtered and concentrated in vacuo to give intermediate 18i as a tan solid (13.8 g, 96%). Mass spectrometry: 428.2 (MH ⁺ ).

Step j: 2-(1-(S)-amino-2-phenylethyl)-1-(4-(1,1-dimethylethyloxy)-4-oxobutyl-4-(4-methoxyphenyl)imidazole

Intermediate 18i (2.14 g, 5.0 mmol) was dissolved in 11.5 mL DMF and KHCO ₃ (1.50 g, 15.0 mmol) and 4-bromo-tert-butyl butyrate (6.69 g, 30 mmol) were added in three portions and the mixture was stirred for 18 h at 50 °C. The mixture was then diluted with ether and washed once with saturated NaHCO ₃ solution and once with saturated NaCl solution. The ether layer was removed, dried over Na ₂ SO ₄ , filtered and concentrated to an oil. Column chromatography on silica gel using CH ₂ Cl ₂ as eluent gave the product as an oil.

The crude alkylated product was deprotected by hydrogenation in acetic acid using 10% Pd on carbon as catalyst. The catalyst was then filtered off and the solvent was evaporated under reduced pressure. The residue was dissolved in AcOEt and washed with saturated NaHCO ₃ solution and saturated NaCl solution, dried over Na ₂ SO ₄ and concentrated to give intermediate 18j as an oil (450 mg), which was used without further purification.

Step k: 2-(1-(S)-((Boc-Trp-D-Trp-Lys(Cbz)-Val)-amino-2-phenylethyl)~1-((4-(1,1-dimethylethoxy)-4-oxo)butyl-4-(3-methoxyphenyl)imidazole

The solution synthesis was carried out in a manner analogous to that described in step 1d except that Boc-Trp-OSu was used instead of Fmoc-Tyr(OBzl)-OSu and Fmoc-Tyr(OBzl)OAt was used instead of Fmoc-Val-F to give intermediate 18k. Yield = 1.03 g (81%).

Step 1: 2-(1-(S)-((H-Trp-D-Trp-Lys(Cbz)-Val)-amino-2-phenylethyl)-1-((4-hydroxy-4-oxo)butyl4-(3-methoxyphenyl)imidazole

Intermediate 18k was treated with a solution containing (i-Pr) ₃ SiH (593 μΐ, 2.90 mmol) in 10 mL Tfa and the mixture was allowed to react for 1 h. The reaction was concentrated and triturated » · · » 0 · · *

0 · 0 0 * 000 • 0 0 0 0 0 0 • 000 000 0 0 • 0 0 · 0 0 0

000 00 00 · 00 00 0 with 1:1 ether:hexane to give intermediate 181 as a tan solid which was used in the next step without further purification. Mass spectrometry: 1267.7 MH ⁺ .

Step f: cyclo[Trp-D-Trp-Lys(Cbz)-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-(y)Abu]

Intermediate 181 was dissolved in 20 mL DMF and 4-methylmorpholine (159 μΐ, 1.45 mmol), HOBt (196 mg, 1.45 mmol) and EDC (278 mg, 1.45 mmol) were added and the reaction was stirred overnight. The reaction was concentrated in vacuo and purified by flash chromatography on silica gel using CH ₂ Cl ₂ :MeOH (9:1) as eluent to give intermediate 18f. Yield = 220 mg (24%). Mass spectrometry: 1249.7 MH ⁺ .

Step g: cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-(y)Abu]

Intermediate 18f (220 mg, 176 pmol) was partially hydrogenated in acetic acid under 30 psi H ₂ at room temperature using 10% Pd on carbon as a catalyst for 14 h. The catalyst was filtered off and the filtrate was concentrated in vacuo. The crude mixture was purified by preparative HPLC on a C ₁₈ column using a gradient of 0% to 75% CH ₃ CN/0.1% Tfa over 40 min. The pure product fractions were combined, concentrated and lyophilized (2 x 10 mL 0.5% HCl, then 1 x 10 mL water) to give the title compound of Example 18, 72 mg (37%). Mass spectroscopy: 1115.6 MH ⁺ .

Example 19 cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(4-methoxyphenyl)imidazole)-Gly]

Example 19 was prepared according to Scheme 3 in a similar manner as described in Example 18 with the following differences:

Step j: 2-(1-(S)-amino-2-phenylethyl)-1-(2-(1,1-dimethylethyloxy)-2-oxo-ethyl)-4-(4-methoxyphenylimidazole)

Intermediate 181 (854 mg, 2.0 mmol) was dissolved in 10 mL DMF and tert-butyl bromoacetate (646 μΐ, 4.0 mmol) and K ₂ CO ₃ (552 mg, 4.0 mmol) were added and the reaction was stirred overnight at room temperature. The solvent was removed under reduced pressure and the residue was dissolved in EtOAc and washed with saturated NaCl solution. The ethyl acetate layer was dried over Na ₂ SO ₄ , filtered and concentrated in vacuo to give 1.02 g as a foam. Mass spectrometry: 428.2 MH ⁺ . NMR (300 MHz, DMSO-d ₆ ), 7.85-8.0 (1H, d), 7.6-7.75 (2H, d), 7.857.95 (1H, s), 7.1-7.35 (10H, m), 6.9-7.0 (2H, d), 4.75-5.05 (5H, m), 3.7-3.9 (3H, s), 3.1-3.4 (2H, m), 1.3-1.5 (9H, s).

The white foam of the intermediate (1.02 g, 1.88 mmol) was dissolved in acetic acid (50 mL) containing 10% Pd on carbon (50 mg) and hydrogenated at room temperature under a hydrogen atmosphere (30 psi) for 10 h. The catalyst was then filtered off and 2N HCl (940 μΐ, 1.88 mmol) was added. The mixture was lyophilized once and then lyophilized again from 20% CH ₃ CN/H ₂ O to give intermediate 19j as a light brown solid (862 mg) which was used without further purification. Mass spectroscopy: 408.2 MH ⁺ .

Step g: Catalytic hydrogenation and work-up was carried out similarly to step 18g to give the title compound (22 mg, 4%) as a white solid. Mass spectroscopy: 1088.2 MH ⁺ .

Example 20 cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(phenyl)imidazole)-Gly]

Example 20 was prepared according to Scheme 3 in a similar manner to that described in Example 18 except that 2-bromoacetophenone was used instead of 2-bromo-3'methoxyacetophenone in step i. Mass spectroscopy: 1057.4 MH ⁺ .

Example 21 cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-methoxyphenyl)imidazole)-(s)Ahx]

Example 21 was prepared according to Scheme 3 in a similar manner as described in Example 18 with the following differences:

Step j: 2-(1-(S)-Amino-2-phenylethyl)-1-(6-(ethoxy)-6-oxohexyl)-4-(3-methoxyphenyl)imidazole

Intermediate 21i (855 mg, 2.0 mmol) was dissolved in 8.0 mL DMF and treated with KHCO ₃ (200 mg, 2.0 mmol) and ethyl 6-bromohexanoate (3.56 mL, 20 mmol) for 8 h at 120 °C. The mixture was concentrated and the residue was purified by column chromatography on silica gel using 2:1/hexane:EtOAc as eluent to give pure product as a gum (0.94 g)

The crude alkylated product was deprotected by hydrogenation in acetic acid using 10% Pd on carbon as catalyst. The catalyst was then filtered off and the solvent was evaporated under reduced pressure. The residue was dissolved in dilute HCl, concentrated and lyophilized to give intermediate 21j as a pale yellow solid, (720 mg, 91%), which was used in the next step without further purification. Mass spectrometry: 436.2 MH ⁺ .

• · • · · · · * « · • ···· · · · · · · · · · · · «* ···· ·> ··· ·· «···

Step to Step 1: 2-(1-(S)-((H-Trp-D-Trp-Lys(Boc)-Tyr(OBzI)-2-(1-(S)-amino-2-phenylethyl)-1-(6-(ethoxy)-6-oxohexyl)-4-(3-methoxyphenyl)imidazole)

Fmoc-Tyr(OBzl)-OAt was prepared by stirring Fmoc-Tyr(OBzl)-OH (493 mg, 1.00 mmol), HOAt (136 mg, 1.0 mmol) and DCC (206 mg, 1.0 mmol) in 8 mL ethyl acetate for 0.5 h and then filtering off the dicyclohexylurea. The resulting solution was added to a solution of intermediate 2lj (457 mg, 0.9 mmol) in 4 mL EtOAc and the mixture was stirred with saturated NaHCO ₃ solution (10 mL) until the reaction was complete according to mass spectrometry. The aqueous layer was removed and the EtOAc layer was dried over Na ₂ SO ₄ , filtered and treated with tris(2aminoethyl)amine (2.7 mL). The mixture was stirred vigorously for 0.5 h. The ethyl acetate layer was washed with saturated NaCl solution (2 x 60 ml) and then with 10% phosphate buffer adjusted to pH = 5.5 (3 x 15 ml).

The intermediate was sequentially deprotected and coupled with Fmoc-Lys(Cbz)-OSu, Fmoc-D-Trp-Osu and Fmoc-Trp-Osu in a similar manner as described above for the Fmoc-Tyr(OBzl)-OAt cycle. Final Fmoc deprotection afforded the N-terminally deprotected intermediate as the ethyl ester. The ethyl acetate layer was dried over Na ₂ SO ₄ , filtered and diluted with four volumes of hexane. The solvent was decanted and the residue was triturated with hexane to give the product as a solid (0.67 g, 58%), which was used without further purification. Mass spectroscopy:

1289.6 MH ⁺ .

The ethyl ester was removed by reacting the intermediate in 5 mL methanol with 1.7 M NaOH solution (1.7 mL) overnight. The mixture was adjusted to pH = 8.2 with 5% HCl solution and the solvents were removed under reduced pressure. The residue was dissolved in DMF, NaCl was removed by filtration and the DMF solution was used in the next step without further purification.

Cyclization and deprotection were carried out in a manner analogous to Example 18 to afford the title compound of Example 21 as a white powder, 62 mg. Mass spectroscopy:

1143.9 MH ⁺ .

Example 22 cyclo[Trp-D-Trp-Lys-Tyr(Bzl)-Phe Ψ (4-(3-hydroxyphenyl)imidazole)-(γ)Abu]

Example 22 was prepared according to Scheme 3 in a manner similar to Example 18 with the following differences:

Step j: 2-( 1 -(S)-Amino-2-phenylethyl)-1 -(4-(ethoxy-4-oxobutyl)-4-(4-hydroxyphenyl)imidazole • · • · 9

9 9 9

9 9

9 9 • 99

9 9 99

A » · 9 ·

Intermediate 22i (2.0 g, 4.68 mmol) was dissolved in 7.0 mL DMF and treated with KHCO ₃ (468 mg, 4.68 mmol) and ethyl 4-bromobutyrate (6.70 mL, 46.8 mmol) and stirred at 100 °C for 30 h. The mixture was diluted with ether and washed once with saturated NaHCO 3 and once with saturated NaCl. The ether layer was dried over Na ₂ SO ₄ , filtered and concentrated to give an oil. Column chromatography on silica gel using dichloromethane as eluent gave the product as an oil (2.53 g, 94%). Mass spectroscopy: 542.3 MH ⁺ .

The crude alkylated product (2.53 g, 4.67 mmol) in 50 mL of dichloromethane was added dropwise over 15 min at -10 °C to a solution of 1M BBr ₃ /hexane (23.4 mL) in 250 mL of dichloromethane. The mixture was allowed to warm to room temperature and stirred for 2 h. Ethanol (40 mL) was then added to the mixture and the mixture was concentrated to about 50 mL. The solution was diluted with 100 mL of ethanol and allowed to stir overnight at room temperature. The mixture was concentrated under reduced pressure and the residue was partitioned between EtOAc and saturated NaHCO ₃ solution. The ethyl acetate layer was dried over Na ₂ SO ₄ , filtered and concentrated under reduced pressure to give an oil (1.41 g, 76%), which was used in the next reaction without protection of the phenolic group. Mass spectrometry: 394.3 MH ⁺ .

· · 9

9 9 9

9 9

9 9

9 9

9*

9

9

HPLC retention times

Example number: HPLC system Retention time (minutes) 1 A 13.65 2 A 18.50 3 A 16.03 4 B 6.97 5 C 20.41 6 C 11.75 7 D 9.53 8 B 11.02 9 E 7.69 10 J 6.02 11 F 4.18 12 G 4.11 13 H 5.50 14 G 6.16 15 I 17.03 16 To 9.12 17 J 8.11 18 J 8.86 19 L 6.47 20 M 6.65 21 G 8.14 22 N 12.10

« A

49 • · A A · · A • * A A A • A HPLC systems: A. Gradient: 20-80% CH3CN /0.1% Tfa, 24min. Flow rate: 1.0 ml / min. Detection: 254nm Column: VYDAC® Protein and Peptide Cl8 B. Gradient: 35-50% CH3CN /0.1% Tfa, 24min. Flow rate: 1.0 ml / min. Detection: 254nm Column: VYDAC® Protein and Peptide Cl8 C. Gradient: 32-64% CH3CN / 0.1% NH4OAC, 24min. Flow rate: 1.0 ml / min. Detection: 254nm Column: VYDAC® Protein and Peptide Cl8 D. Gradient: 20-60% CH3CN / 0.1% Tfa, 24min. Flow rate: 1.0 ml / min. Detection: 254nm Column: VYDAC® Protein and Peptide Cl8 E. Gradient: 55-75% CH3CN / 0.1% Tfa, 24min. Flow rate: 1.0 ml / min. Detection: 220nm Column: Phenomenex LICHROSPHERE® 5 RP18 (Phenomenex, 2320 W) 205* St., Torrance, CA) F. Gradient: 60 . CH3CN /0.1% Tfa, isocratic Flow rate: 1.0 ml / min. Detection: 254nm Column: VYDAC® Protein and Peptide C18 G: Gradient: 50% CH3CN / 0.1% Tfa, isocratic Flow rate: 1.0 ml / min Detection: 254nm Column: VYDAC® Protein and Peptide C18

• · · · * · · • f · « * » ·« · · · • · · * · · « » · · 9 · · · « · • · 9 9 9 9 9

999 9999 99 999 99 9

H. Gradient: 38% CH3CN/0.1% Tfa, isocratic Flow rate: 1.0 ml/min.

Detection: 254nm

Column: VYDAC® Protein and Peptide Cl8

I. Gradient: 20 - 40% CH3CN / 0.1% Tfa, 24 minutes Flow rate: 1.0 ml /min.

Detection: 254nm

Column: VYDAC® Protein and Peptide C18

J. Gradient: 50% CH3CN / 0.1% Tfa, isocratic Flow rate: 1.0 ml /min.

Detection: 254nm

Column: NUCLEOSIL™ Cl 8, 5 micron (Alltech Associates, 2051,

Waukegan Rd., Deerfield, Illinois)

K. Gradient: 40% CH3 CN / 0.1% Tfa, isocratic Flow rate: 1.0 ml / min.

Detection: 254nm

Column: NUCLEOSIL™ C18, 5 micron

L. Gradient: 52% CH3CN/0.1% Tfa, isocratic Flow rate: 1.0 ml/min.

Detection: 254nm

Column: NUCLEOSIL™ Cl8, 5 micron

M. Gradient: 50% CH3CN / 0.1% Tfa, isocratic Flow rate: 1.0 ml /min.

Detection: 254nm

Column: NUCLEOSIL™ Cl8, 5 micron

N. Gradient: 48% CH3CN / 0.1% Tfa, isocratic Flow rate: 1.0 ml / min.

Detection: 254nm

Column: NUCLEOSIL™ Cl8, 5 micron

; )

Industrial applicability

The compounds of the present invention are suitable for the manufacture of pharmaceutical products useful for the treatment of a wide range of diseases related to the activity of somatostatin in the body.

Claims (25)

PATENT CLAIMS A compound of formula I or a pharmacologically acceptable salt thereof, wherein Y and Z for each occurrence are each independently D- or L- natural or non-natural amino acid; n is independently 0 to 50 for each occurrence, provided that both n cannot be 0 at the same time; m is 0 or an integer from 1 to 10; a is H or R ¹ ; b is OH, -OR ¹ or -NR ⁹ R ⁹ ; or a together with a b amidic bond; R ¹ is independently H, (C 1 -C ₄ ) alkyl or aryl (C ₁ -C ₄ ) alkyl; R ² is H or an optionally substituted group selected from the group consisting of (C 1 -C 4) alkyl, phenyl, phenyl (C 1 -C 4) alkyl or heterocyclyl (C 1 -C 4) alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents each independently selected from the group consisting of (C 1 -C 4) alkyl, (C 3 -C 8) cycloalkyl, -OR ⁶ , -S (O) q R ⁷ , -N (R ⁹ R ⁹ ), -NHCO-R ⁶ , -NHSO ² R ⁹ , -CO ² R ⁹ , -CONR ⁹ R ⁹ and -SO ₂ NR ⁹ R ⁹ , wherein q is 0, 1, 2 or 3; R ³ and R ⁴ are each independently H, halogen or an optionally substituted group selected from the group consisting of (C 1 -C ₄ ) alkyl, (C ₃ -C ₈ ) cycloalkyl, aryl and aryl (C 1 -C ₄ ) alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents selected from the group consisting of OH, (C 1 -C ₄ ) alkyl, (C 1 -C ₄ ) alkoxy, aryloxy, aryl (C 1 -C ₄ ) alkoxy, N ( R ⁹ R ⁹ ), -COOH, -CONR ⁹ R ⁹ and halogen; ·· ·· · ·· · 4 4 4 9 9 9 9 9 9 9 4 9 9 4 9 4 4 4 4 9 9 9 4 4 5 Or R ³ and R ⁴ together with the carbons to which they are attached form an optionally substituted aryl, wherein the aryl is optionally substituted with one or more substituents independently selected from the group consisting of OH, (C 1 to C ₄₎ alkyl, (C 1 -C ₄ ) alkoxy, aryloxy, aryl (C 1 -C ₄ ) alkoxy, -NR ⁹ R ⁹ , COOR ⁵ , -CONR ⁹ R ⁹ and halogen; R ⁵ at each occurrence is independently H or an optionally substituted group is selected from the group consisting of (C 1 -C ₄ ) alkyl and aryl (C 1 -C ₄ ) alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents, wherein each independently selected from the group consisting of (C 1 -C ₄ ) alkyl, OH, (C ₁ -C ₄ ) alkoxy, aryloxy, NO ₂ , aryl (C 1 -C ₄ ) alkoxy, NR ⁹ R ⁹ , -COOH, -; CONR ⁹ R ⁹ and halogen; R ⁶ at each occurrence is independently selected from the group consisting of H, (C 1 -C ₄ ) alkyl, (C 1 -C ₄ ) alkoxy, aryl (C 1 -C ₄ ) alkyl, and aryl (C 1 -C ₄ ) alkoxy, R ⁷ is H when q is 3 or R ⁷ is at each occurrence independently selected from the group consisting of (C ₁ to C ₄ ) alkyl, aryl or aryl (C 1 to C ₄ ) alkyl when q is 0,1 or 2, and R ⁹ at each occurrence is independently selected from the group consisting of H, NO _{2, (C}} to C ₄₎ alkyl, aryl and aryl (C, to C ₄₎ alkyl. A compound of formula II, or a pharmaceutically acceptable salt thereof, wherein Y and Z are each independently D- or L- natural or non-natural amino acids for each occurrence; m is 0 or an integer from 1 to 10; n is independently 0 to 6 for each occurrence, R ¹ at each occurrence is independently H, (C 1 -C ₄ ) alkyl or aryl (C 1 -C ₄ ) alkyl; • 99 ·· 9 99 · 9 9 9 9 9 9 999 999 99 999 99 » 999 9999 99 999 99 999 R ² is H or an optionally substituted group selected from the group consisting of (C 1 to C 4) alkyl, phenyl, phenyl (C 1 to C 4) alkyl or heterocyclyl (C 1 to C 4) alkyl, wherein the optionally substituted group is optionally substituted with one or a plurality of substituents each independently selected from the group consisting of (C 1 to C 4) alkyl, cycloalkyl, -OR ⁶ , -S (O) q R ⁷ , -N (R ⁹ R ⁹ ), -NHCO-R ⁶ , NHSO ² R ⁹ -CO ² R ⁹ , -CONR ⁹ R ⁹ and -SO ₂ NR ⁹ R ⁹ wherein q is 0, 1, 2 or 3; R ³ and R ⁴ are each independently H, halo or an optionally substituted group selected from the group consisting of (C 1 -C ₄ ) alkyl, cycloalkyl, aryl and aryl (C 1 -C ₄ ) alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents selected from the group consisting of OH, (C 1 -C ₄ ) alkyl, (C 1 -C ₄ ) alkoxy, aryloxy, aryl (C 1 -C ₄ ) alkoxy, -N (R ⁹ R ⁹ ), COOH, -CONR ⁹ R ⁹ and halogen; or R ³ and R ⁴ together with the carbons to which they are attached form an optionally substituted aryl, wherein the aryl is optionally substituted with one or more substituents each independently selected from the group consisting of OH, (C 1 -C ₄ ) alkyl, (C 1 -C ₄ ) alkoxy, aryloxy, aryl (C 1 -C ₄ ) alkoxy, -NR ⁹ R ⁹ , -COOR ⁵ , -CONR ⁹ R ⁹ and halogen; R ⁵ at each occurrence is independently H or an optionally substituted group is selected from the group consisting of (C 1 -C ₄ ) alkyl and aryl (C 1 -C ₄ ) alkyl, wherein the optionally substituted group is optionally substituted with one or more substituents, wherein each is independently selected from the group consisting of (C 1 -C ₄ ) alkyl, OH, (C ₁ -C ₄ ) alkoxy, aryloxy, aryl (C 1 -C ₄ ) alkoxy, -NR ⁹ R ⁹ , -COOR ⁵ , -CONR ⁹ R ⁹ and halogen; R ⁶ is at each occurrence independently selected from the group consisting of H, (C 1 -C ₄ ) alkyl, (C 1 -C ₄ ) alkoxy, aryl (C 1 -C ₄ ) alkyl and aryl (C 1 -C ₄ ) alkoxy , R ⁷ is H when q is 3 or R ⁷ at each occurrence is independently selected from the group consisting of (C 1 -C ₄ ) alkyl, aryl or aryl (C 1 -C ₄ ) alkyl when q is 0, 1 or 2, and R ⁹ is at each occurrence independently selected from the group consisting of H, NO ₂ , (C 1 -C ₄ ) alkyl, aryl and aryl (C 1 -C ₄ ) alkyl. X ¹ is a natural or unnatural D- or La-amino acid, wherein X ¹ is Phe, Nal, Trp, Tyr, Pal or His, the aromatic ring of which is optionally substituted on carbon or nitrogen by R ⁶ or when X ¹ is Ser or Thr the side chain oxygen is optionally substituted with one or more R ¹ ; X ² is D- or L-Trp, N-methyl-1-D-Trp or N-methyl-L-Trp; X ³ is Lys, α-N-methyl-Lys or ε-Ν- (C 1 -C ₄ ) alkyl-Lys or 8-N- [aryl- (C 1 -C ₄ ) alkyl] -Lys; 00 00 ♦ · · 00 0 0 · 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 • 0 0 0 0 · ♦ · Φ 0 X ⁴ is a natural or unnatural D- or La-amino acid, wherein X ⁴ is Phe, Nal, Trp, Tyr or His, the aromatic ring of which is optionally substituted on carbon or nitrogen substituent ^R8 or when ^X4 is Ser, Thr or Tyr may be oxygen of the side chain substituted with one or more substituents ^R! . A compound of formula II according to claim 2, wherein each n is 2; m is 0 or 1 to 5; R ¹ at each occurrence is independently H, methyl or aryl (C ₁ -C ₄ ) alkyl; R ² is an optionally substituted group selected from the group consisting of phenyl- (C 1 to C ₄ ) alkyl, and heterocyclyl- (C 1 to C ₄ ) alkyl, wherein the optionally substituted group is substituted with a substituent selected from the group consisting of (C 1 to C ₄₎ ) alkyl and -OR ^6a ; R ³ and R ⁴ are each independently H, halogen or an optionally substituted group selected from the group consisting of (C 1 to C ₄ ) alkyl and aryl, wherein the optionally substituted group is optionally substituted with a substituent selected from the group consisting of OH, (C 1 to C) ₄ ) alkoxy, aryloxy and halo. A compound of formula II according to claim 3, wherein X 'is Phe, Nal, Trp, Tyr, Pal or His, wherein the aromatic ring is optionally substituted on carbon or nitrogen with R ⁶ , and X ⁴ is Val, Abu, Ser, Thr, Nal, Trp, Tyr or His, wherein the aromatic ring in Nal, Trp, Tyr and His is optionally substituted on carbon and / or nitrogen with R ⁸ or when X ⁴ is Ser, Tyr or Thr, the oxygen in their side chain is optionally substituted with R ¹ . A compound of formula II according to claim 4, wherein X ¹ is Phe, Trp or Tyr, the aromatic ring of which is optionally substituted on carbon or nitrogen by R ⁶ , X ² is D-Trp or N-methyl-D-Trp, X ³ is Lys or α-N-methyl-Lys, X ⁴ is Val, Thr, Abu, Nal or Tyr, wherein the oxygen in the hydroxyl group of the side chain of Thr and Tyr is optionally substituted with R ¹ ; R ¹ for each occurrence is independently H, methyl or benzyl; • «· ·· · 44 4 4 9 4 49 4 9 4 4 4 4 4 5 4 9 4 4 4 4 4 4 4 5 4 4 4 9 4 449 4444 44 444 44 444 R ² is an optionally substituted group selected from the group consisting of phenylmethyl and heterocyclylmethyl, wherein the optionally substituted group is substituted with a substituent selected from the group consisting of (C 1 to C ₄ ) alkyl and -OR ⁶ ; R ³ is (C 1 -C ₄ ) alkyl or optionally substituted aryl, wherein the optionally substituted aryl is substituted with a substituent selected from the group consisting of OH, (C 1 -C ₄ ) alkoxy, aryloxy and halogen; R ^{4 is} H, and R ⁶ for each occurrence is independently selected from the group consisting of H and aryl (C 1 -C ₄ ) alkoxy. A compound of formula II according to claim 5, wherein X 1 is Phe, Trp, Tyr or Tyr (Obzl); X ⁴ is Val, Thr, Abu, Nal or Tyr, wherein the hydroxy of Thr and Tyr is optionally substituted with benzyl; m is 0, 2 or 4; R ² is an optionally substituted group selected from the group consisting of phenylmethyl or 3-indolylmethyl, wherein the optionally substituted group is optionally substituted with -OR ⁶ ; and R ³ is 1,1-dimethylethyl or optionally substituted aryl, wherein the optionally substituted aryl is optionally substituted with a group selected from the group consisting of OH, (C 1 -C ₄ ) alkoxy and halogen. A compound of formula II according to claim 6, wherein R ² is phenylmethyl; R ³ is 1,1-dimethylethyl or optionally substituted phenyl, wherein optionally substituted phenyl is optionally substituted with OH or OCH _3, and R ⁶ for each occurrence is independently selected from the group consisting of H or benzylmethoxy. A compound of formula I according to claim 1, wherein said compound is H-Trp-D-Trp-Lys-Abu-Phe (4- (3-methoxyphenyl) imidazole) -Gly-OH. A compound of formula I according to claim 7, wherein said compound is cyclo [Tyr-D-Trp-Lys-Val-Phe 2 - (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Tyr (OBzl) -D -Trp-Lys-Val-Phe Ψ (4- (3-methoxyphenyl) imidazole) -Gly], • 0 0 · • 0 0 0 0 0 0 0 0 00 Cyclo [Trp-D-Trp-Lys-Val- PheΨ (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Val-PheΨ (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [Trp-D- Trp-Lys-Thr (OBzl) -Phe- (4- (3-methoxyphenyl) imidazole) -Glyj, cyclo [Trp-D-Trp-Lys-Thr-Phe- (4- (3-hydroxyphenyl) imidazole) -Gly ], cyclo [Trp-D-Trp-Lys-Abu-Phee (4- (3-methoxyphenyl) imidazole) -Gly), cyclo [Phe-D-Trp-Lys-Tyr (OBzl) -PheΨ (4- (1,1-dimethylethyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Val-Phe (4- (3-methoxyphenyl) imidazole-Gly), cyclo [Phe-D-Trp-Lys-Tyr] (OBzl) -Phe 4- (4- (3-methoxyphenyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Tyr-Phe Ψ (4- (3-methoxyphenyl) imidazole-Gly], cyclo [Phe- D-Trp-Lys-Tyr-Phe - (4- (3-hydroxyphenyl) imidazole-Gly), cyclo [Trp-D-Trp-lys-Tyr (Bzl) -Phe - (4- (3-methoxyphenyl) imidazole-Gly), cyclo [Tyr-D-Trp-Lys-Val-Phee (4- (3-hydroxyphenyl) imidazole-Gly]), cyclo [Phe-D-Trp-Lys-Nal-PheΨ (4- (3-hydroxyphenyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe] (4- (3-methoxyphenyl) imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr (OBzl) ) -Phe- (4- (3-methoxyphenyl) imidazole (s) Abu), cyclo [Trp-D-Trp-Lys-Tyr (OBzl) -Phe- (4- (4-methoxyphenyl) imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr (OBzl) -Phe (4- (phenyl) imidazole-Gly]), cyclo [Trp-D-Trp-Lys-Tyr (OBzl) -Phe (4- (3-)) methoxyphenyl) imidazole- (c) Ahx] or cyclo [Trp-D-Trp-Lys-Tyr (OBzl) -Phe- (4- (3-hydroxyphenyl) imidazole- (s) Abu). A compound of formula I according to claim 9, wherein said compound is cyclo [Tyr-D-Trp-Lys-Val-Phe 2 - (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Tyr (OBzl) -D -Trp-Lys-Val-PheΨ (4- (3-methoxyphenyl) imidazole) -Gly, cyclo [Trp-D-Trp-Lys-Val-PheΨ (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Val-Phe (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Thr (OBzl) -Phe (4- (3 -methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Thr-Phe [4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Abu-Phe] Ψ (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Phe-D-Trp-Lys-Tyr (OBzl) -Phe Ψ (4- (1,1-dimethylethyl) imidazole-Gly], cyclo [Phe -D-Trp-Lys-Val-Phe - (4- (3-methoxyphenyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Tyr-Phe - (4- (3-hydroxyphenyl) imidazole-Gly]) or 9 99 9 9 9 9 9 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 3-hydroxyphenyl) imidazole-Gly]. A compound of formula I according to claim 10, wherein said compound is cyclo [Tyr-D-Trp-Lys-Val-Phe 2 - (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp- Lys-Val-PheΨ (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Val-PheΨ (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [ Trp-D-Trp-Lys-Thr-PheΨ (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Abu-PheΨ (4- (3-methoxyphenyl) imidazole)) -Gly], cyclo [Phe-D-Lys-Val-Phe - (4- (3-methoxyphenyl) imidazole-Gly]) or cyclo [Tyr-D-Trp-Lys-Val-Phe - (4- (3-hydroxyphenyl) ) imidazole-Gly]. A compound of formula I according to claim 11, wherein said compound is cyclo [Tyr-D-Trp-Lys-Val-Phe 2 - (4- (3-methoxyphenyl) imidazole) -Glyj, cyclo [Trp-D-Lys-Val] -Phe- (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Thr-Phe- (4- (3-hydroxyphenyl) imidazole) -Gly] and cyclo [Tyr-D] -Trp-Lys-Val-Phe - (4- (3-hydroxyphenyl) imidazole) -Gly]. A compound of formula I according to claim 9, wherein said compound is cyclo [Tyr-D-Trp-Lys-Val-Phe 2 - (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp- Lys-Val-PheΨ (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Val-PheΨ (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [ Trp-D-Trp-Lys-Thr (OBzl) -Phe- (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Thr-PheΨ (4- (3-hydroxyphenyl) (imidazole) -Gly], cyclo [Trp-D-Trp-Lys-Abu-PheΨ (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Phe-D-Trp-Lys-Tyr (OBzl) - PheΨ (4- (1,1-dimethylethyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Tyr (OBzl) -PheΨ- (4- (3-methoxyphenyl) imidazole-Gly], cyclo [Phe] -D-Trp-Lys-Tyr-Phe - (4- (3-hydroxyphenyl) imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe - (4- (3-methoxyphenyl) imidazole) -Gly], cyclo [Tyr-D-Trp-Lys-Val-Phe 1 - (4- (3-hydroxyphenyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe 1 - (4- (3 -hydroxyphenyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe] (4- (3-methoxyphenyl) imidazole-Gly]) Cyclo (Trp-D-Trp-Lys-Tyr (Bzl) -Phe) (4- (3-methoxyphenyl) imidazole) - (y) Abu], cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe-4- (4-methoxyphenyl) imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr (Bzl) ) -Phe- (4- (phenyl) imidazole-Gly], cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe- (4- (3-methoxyphenyl) imidazole- (s) Ahx) or cyclo [ Trp-D-Trp-Lys-Tyr (Bzl) -Phe- (4- (3-hydroxyphenyl) imidazole (s) Abu). A compound of formula I according to claim 13, wherein said compound is cyclo [Trp-D-Trp-Lys-Thr-Phe 2 - (4- (3-hydroxyphenyl) imidazole) -Gly], cyclo [Trp-D-Trp- Lys-Tyr (Bzl) -Phe - (4- (3-methoxyphenyl) imidazole-Gly], cyclo [Phe-D-Trp-Lys-Nal-Phe - (4- (3-hydroxyphenyl) imidazole-Glyj), cyclo [ Trp-D-Trp-Lys-Tyr (Bzl) -Phe (4- (3-methoxyphenyl) imidazole- (s)) Abuj, cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe (4-) (4-methoxyphenyl) imidazole-Glyj or cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe- (4- (phenyl) imidazole-Gly]). A compound of formula I according to claim 14, wherein said compound is cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe- (4- (3-methoxyphenyl) imidazole-Gly]), cyclo [Trp-D- Trp-Lys-Tyr (Bzl) -Phe- (4- (3-methoxyphenyl) imidazole- (s) Abuj, cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe) (4- (4-methoxyphenyl) imidazole-Gly] or cyclo [Trp-D-Trp-Lys-Tyr (Bzl) -Phe- (4- (phenyl) imidazole-Glyj. 16. A pharmaceutical composition comprising an effective amount of a compound of claim 1, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. 17. A pharmaceutical composition comprising an effective amount of a compound of claim 2, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. 18. A method of eliciting a somatostatin receptor agonist effect in a mammal in need thereof, comprising administering to said mammal an effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof. ft ft ft 9 ft ft ft ft ft e e ft ft ft A A ft ft ·· ··· ·· ft ·· 19. A method of eliciting a somatostatin receptor agonist effect in a mammal in need thereof, comprising administering to said mammal an effective amount of a compound according to claim 2 or a pharmaceutically acceptable salt thereof. 20. A method of eliciting a somatostatin receptor antagonist effect in a mammal in need thereof, comprising administering to said mammal an effective amount of a compound according to claim 1 or a pharmaceutically acceptable salt thereof. 21. A method of eliciting a somatostatin receptor antagonist effect in a mammal in need thereof, comprising administering to said mammal an effective amount of a compound of claim 2 or a pharmaceutically acceptable salt thereof. 22. A method of treating prolactin secreting adenomas of restenosis, diabetes mellitus, hyperlipidemia, insensitivity to insulin, Syndrome X, angiopathia, proliferative retinopathy, dawns syndrome, neuropathy, gastric acid secretion, peptic ulcers, enterocutaneous and pancreaticocutromic pustules, watery diarrhea syndrome, AIDS-induced diarrhea, chemotherapy-induced diarrhea, acute or chronic pancreatitis, hormone-secreting gastrointestinal tumors, cancer, hepatoma, angiogenesis, inflammatory diseases, arthritis, chronic graft rejection, angioplasty, bleeding from graft vascular bleeding or graft vascular bleeding, characterized in that said mammal is administered with a compound of claim 1 or a pharmaceutically acceptable salt thereof. 23. A method of treating prolactin secreting adenomas of restenosis, diabetes mellitus, hyperlipidemia, insensitivity to insulin, syndrome X, angiopathia, proliferative retinopathy, dawns syndrome, neuropathy, gastric acid secretion, peptic ulcers, enterocutaneous and pancreaticocutromic stroke, pustreaticocutaneous pustules, watery diarrhea syndrome, AIDS-induced diarrhea, chemotherapy-induced diarrhea, acute or chronic pancreatitis, hormone-secreting gastrointestinal tumors, cancer, hepatoma, angiogenesis, inflammatory diseases, arthritis, chronic graft rejection, angioplasty, bleeding from graft vascular bleeding or graft vascular bleeding, characterized in that said mammal is administered with a compound according to claim 2 or a pharmaceutically acceptable salt thereof. 24. A method of inhibiting helicobacter pylori proliferation in a mammal, comprising administering to said mammal the compound of claim 1 or a pharmaceutically acceptable salt thereof. 25. A method of inhibiting helicobacter pylori proliferation in a mammal, comprising administering to said mammal the compound of claim 2 or a pharmaceutically acceptable salt thereof.