MC666A1 - Amidino-ureas and their preparation - Google Patents

Description

PATENT FOR INVENTION

Amidin-ureas >and their pre-aging.

Company called: THE WELLCOME FOUNDATION LIMITED

Over the past 40 years, a number of safe and highly effective synthetic chemicals have been discovered for treating malaria in humans. These chemicals include chloroquine.

5 [7-chlqro-4-(4-diethylamiro-l-methylbutylamino —: 7-

quinoline, proguanil [l-(p-chlorophenyl)-5-isopropyl-

biguanide], primaquine [8-(4-afflino-l-methyl-butyl-amino)-6-methoxyquinoline], and pyrimethamine [2,4-diamino-5-(p-chloro-phenyl)-6-ethylpyrimidine]. All of these substances are commonly used to treat various forms of the infection, but none of them alone is perfectly suited for the treatment and prophylaxis of all malaria infections. Resistance of malaria parasites to these drugs has been reported in various parts of the world, and this has stimulated research to find new substances to enhance the means of control.

1

/

- 2 -

0^- The 1-(N-alkylamidino)-3-phenylureas constitute a class of synthetic chemicals that were studied in the 1940s for their antimalarial activity, but further research was not deemed necessary.

5 (Curd, F.H.S. and his collaborators J. Chem. Soc., 1949, .

1732). Other L-amidino-3-phenylureas have been studied by

Urbangki ®n i960 and this author reported that, among many monosubstituted l-amidino-3-phenylureas on the phenyl ring,

the strongest activity against the malaria agent Plasmodium

summer

10 gallioaceum in chicken had/observed with 3-amidino-3-(4-nitrophenyl)urea, [Skowronska-Serafin, B & Urbanski, T., tetrahedron, 10, 12-25 (1960)].

The Applicant found that amidinoureas of general formula I below also showed activity against various hematozoa, agents of malaria, in comparative tests carried out on typical infections in laboratory animals.

20

4 (/ \\- NH-CO-NH-C

nh

(I)

NH.

25

30

In this formula:

4

Y is a halogen and Y is a trihalomethyl, nitrile or nitro group in position -3 or a halogen in position -3 or both in positions | and 5 or

4

Y is a trihalomethyl or nitrile group and Y is a hydrogen atom or a halogen or an alkyl group having 1 to 4 carbon atoms in position 2 or 3, or

4

'Y is a nitro group and Y is a trihalomethyl group or a halogen in position 3.

- 3 -

The most interesting substituents for v are

Halogens: chlorine, bromine, and fluorine, particularly chlorine, for trihalomethyl groups, the trifluoromethyl group, and, for alkyl groups, the methyl group. Amidinoureas of formula I, as well as their acid addition salts, are active against P. gallinaceum in chickens and against P. vinckei and P. berghei in mice. Several of them have also proven active against strains of P. gallinaceum resistant to pyrimethamine or a dihydrotriazine, as well as against a strain of P. berghei resistant to chloroquine. Compounds of formula I are also more active against P. gallinaceum and

In many cases, also against P. vinckei, than the known l-amidino-3-(4-nitrophenyl)urea, as indicated by the 15 experimental results given below. Among the compounds of formula i that are most active against p. vinckei are those in which Y4 is a nitrile or trifluoromethyl group and Y a hydrogen atom or a halogen in position 2 or 3, as well as those in which Y4 is a halogen and Y a nitrile or nitro group, a halogen, or a trifluoromethyl group in position 3. These compounds include the following: l-amidino-3-(4-chloro-3-trifluoromethylphenyl)urea, l-amidino-3-(2-chloro-4-cyanophenyl)urea, l-amidino-3-(3-chloro-4-cyanophenyl)urea, l-amidino-3-(3,4-dichlorophenyl)urea,

l-Amidino-3-(4-chloro-3-cyanophenyl)urea and l-Amidino-3-(4-trifluoromethylphenyl)urea, as well as their acid addition salts. Some of the compounds of formula I have also shown activity against other 30 protozoan infections.

-4<~

The activity of the present tenses resides in the base,

- /^e the acid of the addition salt being of lesser importance and needing only be an acid acceptable for pharmaceutical uses. The acid could be for example hydrochloric acid, 5 sulfuric acid, toluene-p-sulfonic acid, p-chlorobenzene-sulfonic acid, maleic or tartaric acid and, preferably, ethane-sulfonic acid or methane-sulfonic acid, which give salts having better solubility than most other salts.

10 The activity of compounds of formula I against the hematozoa of malaria is shown by the results given in Tables II and III, the results of comparative tests carried out with known amidinoureas being indicated in Table I. In these tables, the symbols used have the following meanings:

3+ 1% parasitemia; 2+ 1 to 30% parasitemia

1+ 30 to 60% parasitemia but

+60% parasitemia/levels much lower than in the case of the comparator controls

- no significant difference compared to the control groups

(T) death of animals

All percentages are evaluated and recorded in relation to untreated control animals.

there

25 These results were obtained in the following way,

P. gallinaceum

Blood from the heart of a chicken, previously infected with a normal or resistant strain of Plasmodium gallinaceum, is introduced into a glucose physiological solution containing a sufficient quantity of heparin to prevent coagulation.

and we adjust the volume of the mixture to prepare an inoculum containing one million infected red blood cells per 0.2 ml. The chickens subjected to the trials were infected by introducing 0.2 ml of the inoculum into the jugular vein and then randomly grouped in fives. They were given seven oral doses of the compound to be tested, beginning in the afternoon of the day of infection, followed by two doses per day for the next three days. On the fourth day, blood smears were prepared from all the animals, stained, examined, and the parasitemia of the chickens was assessed, recorded as a percentage relative to untreated control animals. The results of these trials with the formula I compounds against a normal laboratory strain of P. gallinaceum are shown in Table II. A comparison with the results given in Table I shows that the formula I compounds are all active against this parasite at a lower dose than known compounds. Table III further shows the activity against a pyrimethamine-resistant strain of P. gallinaceum and against a triazine-resistant strain. (strain resistant to 4.6-diamino-l-(p-chlorophenyl)-l.2-dihydro-2.2-dimethyl-s-triazine), compounds of formula I are also active at a lower dose than in the case of the known analogue compound, nitrated at position 4.

P. vinckei

Heart blood from a mouse previously infected with P. vinckei is introduced into a glucose physiological saline solution containing sufficient heparin to prevent coagulation, and the volume of the mixture is adjusted to obtain an inoculum containing one million parasitized red blood cells per 0.1 ml. Mice are then infected with 0.1 ml

of this inoculate, via the intraperitoneal route, and the mice are grouped in fives, randomly. They are given seven doses of an experimental compound, orally, beginning the afternoon.

at noon on the day of infection, then two doses per day for the following three days. On the fourth day, blood smears are prepared from all animals, stained, and examined. The parasitemia of the mice is assessed and recorded in the control group.

^percentage compared to animals/untreated.

\ The results of these tests with the compounds of formula I, which are represented in Table II, show that the compounds tested are more active or as active as the known compounds which are indicated in Table I.

Table III shows the results of tests carried out with a chloroquine-resistant strain of P. berghei. These results were obtained in the same way as in the case of

P.vinckei, except that the inoculum -4-.- was adjusted so as to

containing six million parasitized red blood cells per 0.1 ml, and that the mice were bled for a second examination on the eighth day, as well as on the fourth. Table III shows that the compounds of formula I are active against this strain and/or are more active than the known analogous compound, nitrated at position 4.

:

TABLE I

Activities of 1-amidino-3-phenylureas known to be mono-substituted on the phenyl ring, against P. vinckei in mice and against P. gallinaceum in chickens

Reference to previous literature

Substitute on the phenyl ring

Activity against P. vinckei Activity against P. gallinaceum (Dose: mg/kg x 7) (Dose: mg/kg x 7)

100

50

25

20

100

50

25

Chem. Abs.45, 1951, 10208

4-methoxy-

1 +

-

Tetrahedron, 10, 1960, 12-25

4-nitro-

3+

2+

1 +

-

3+

+

-

Chem. Abs. 45, 1951, 10208

3-chloro-

1 +

-

Tetrahedron, 10, 1960, 12-25

4-chloro-

-

(T)

Chem. Abs. 45, 1951, 10208

2-chloro

(T)

-

TABLE II

Activities of formula(I)-substituted L-amidino-3-phenyl-ureas against P. vinckei in mice and P. gallinaceum in chickens

Example No.

Substitute on the phenyl ring

Activity against (Dose:mg./kg.

P.vinckei x 7)

Activity (Dose:

against P. gallinaceum mg/kg. x7)

o o

H

o in o in in

ID CM CM r-H

CM

V-

O if) if)

lO

t-

\0

8 2

T"

o in m

C9 CM t-

lO o

»* s—

OJ

in CM

\0*

m m

CM*

7.9

4-cyano -

3+

2+ 1+ -

3+ 2+

1+

+

-

2,15-19,26,28-30

3-chloro-4-cyano-

3+

2 + 1 +

3+

2+

-

5.

4-cyano-3-methyl-

3+

-

3+

1+

-

' 1

4-chloro-3-cyano-

3+ 2+

1+ -

3+ 2+

1+

-

8, 24, 25, 27, 31, 32

3 «4-dichloro-

3+ 2+ 1+

- -

3+ 1+

-

4

2-bromo-4-cyano-

3 + 2 + 1 + 1 +

-

3+

2+

-

3

2-chloro-4-cyano-

3+ 2+ 2+

+ -

3+(T) 1+

6

4-cyano-2-methyl-

3+ 1+ -

3+ 2+

-

12

4-trifluoromethyl-

3+ 2+ 1+

-

3+

1 +

-

13

4-chloro-3-nitro-

3 +

-

(T) 3+

20

£4. 5-trichloro-

3+

3+ 2+

(T)

1 +

-

14 23

4-chloro-3-trifluoro-methyl-3-chloro-4-nitro-

3+ 3+

3+ 3+ 1+

3+

3+ 3+

3+ 3+

2+ 2+

21

^22

4-ni tro-3-tri fluoro-methyl-

4-cyano-3-fluoro-

3+ 3+

2+ 2+

Ojl

3-Î-

TABLE III

Activities of phenyl ring-substituted 1-amidino-3-phenyl-ureas against resistant strains of P. berghei and P. gallinaceum

Compound or substituent on the phenyl ring

Example No.

Activi resist (]

(Dose; mg/kg x 7) against a strain of P. berghei ante

Activity against a pyrimethamine-resistant strain of P. gallinaceum (Dose: mg/kg x 7)

Activity against a triazine-resistant strain of P. gallinaceum (Dose: mg/kg x 7)

100

50

25

12.5

20

10

5

20

10

5

Chloroquine

-

-

Pyrimethamine

-

+

-

35

A triazine

-

+

-

4-N02

-

+

-

-

-

4-CN

7.9

1 +

1 +

-

2+

-

2+

-

3-C1, 4-CN

2.15-19, 26.28-30

2+

+

-

3+

-

3+

+

-

2—Cl, 4-CN

3

2+

+

-

4-cf3

12

1+

-

2+

-

2+

-

x Triazine is 4,6-diamino-1-(jQ-chlorophenyl)-1.2-dihydro-2.2-dimethyl-s-triazine.

O*

- 10 -

The compounds of formula I can be prepared using all known methods for the preparation of compounds having an analogous chemical structure, although some methods are preferable because they are easier to execute and adapt to industrial-scale manufacturing.

One preparation method involves introducing the oxygen atom of the carbonyl group in place of a reactive group X, such as an imino group, a thio group, or a reactive derivative of such a group, into a compound of formula II, the most advantageous reactive groups being S-alkylic or S-benzyl groups.

5

n - (II)

nh2

As an example of this type of method, one can convert a biguanide of formula II, in which X is an imino group,

into a compound of formula I by reaction with an excess of nitrous acid, preferably at a temperature of 0 to 20° or

0 by hydrolysis with a strong aqueous acid, for example acid

ethanesulfonic acid, methanesulfonic acid, chlorhy-

qbrique, preferably at a temperature of about 20 to 90°C. These (X) can be obtained by a number of methods which are well

(described in the literature (see for example "Chemistry >5 Carbon Compounds" Ed." E.H. Rodd, 1st edition, volume III)

Part A, 1854, pages 198 and following). They can be prepared, for example, by reacting dicyanodiamide with the hydrochloride of a primary aromatic amine, either in a solvent or by fusion, or by removing the elements from the hydrogen sulfide of a guanidine or an isothiourea

- 11 -

having the corresponding substituents, or of an amidino-thio-urea or of a di-thio-biuret having the corresponding substituents.

As another example of this type of method, we can

5. Oxidize an L-amidino-3-phenylthiourea of formula II,

substituted on the sulfur atom and on the

phenyl nucleus, X being for example an S-alkyl group in a compound of formula I, preferably by means of a peroxide,

For example, hydrogen peroxide. S-substituted thiourea

10 can be prepared from l-amidino-3-phenyl-thio-urea

/substituted/

^^corresponding,/on the .'phenyl nucleus, which can itself be obtained by reaction of the appropriate iso-thiocyanate with guanidine.

Another type of method for preparing amidino-15 ureas of formula I is the reaction of guanidine with a reactive derivative of a substituted phenylcarbamic acid, of formula III

20

Y

■4 / (III)

Y

for example an isocyanate (the internal anhydride) or a urea (the amide). Other reactive derivatives that can be used 25 are esters, for example, a urethane, which is preferably reacted with an anhydrous solution of guanidine base. A substituted amide can also be used: for example, the fusion of an N.N-dialkyl-N'-aryl-carbamide with guanidine base will lead to a compound of formula I. Naturally, we see 30 that other reactive derivatives of carbamic acid

- 12 -

Formula III formulas can be used instead of those just indicated.

Yet another type of method for preparing compounds of formula I involves the reaction of an aniline or a reactive aniline derivative, having the appropriate substituents, with a reactive guanidine-carboxylic acid derivative of formula IV

NH

II

A-NH-C - NH2 (IV)

10 For example, nitrile, amide, or ester. Thus, dicyanodiamide of formula IV, that is, the internal anhydride of amide, in which A represents the -CN group, can be reacted with aniline bearing the desired substituents, in the presence of at least twice the equivalent proportion of strong aqueous acid relative to dicyanodiamide, to obtain an amidinourea of formula I. The acid can be a strong aqueous acid such as hydrochloric acid, ethanesulfonic acid, methanesulfonic acid, or an acid of similar strength. It can be seen that the amidinourea is formed via the corresponding biguanide, which is transformed within the mixture itself into amidinourea by the excess acid. One can, of course, if desired, for example for characterization or purification purposes, first isolate the biguanide (using an equimolar equivalent of acid for the reaction) and then convert it to amidinourea in the manner described above. Other examples of this type of method include the reaction of aniline with the appropriate substituents, or of an aniline addition salt with an acid.

pvec a nitrourea of formula IV (A then being the 30 NO2NHC0- group) or with an alkoxycarbonylguanidine (A being by

- 13 -

example the CH^OCO- group or the reaction of a Grignard derivative of aniline with an alkoxycarbonyl-guanidine.

Amidin ureas of formula I can also be obtained by aminolysis / methylene urea of formula V

\ R

v4 V^^-NHCON = (V)

\ R,

Y

in which R and R' are reactive substituents, for example alkoxy or alkylthio groups, or R is an amino group and R' is an alkoxy, alkylthio or thio group,

atyloxy or aralkoxy, for example an ethoxy group.

Amidinoureas of formula I in which the phenyl ring bears a halogen atom or a nitrile group can also be prepared from the corresponding amine compound, by diazotization followed by reaction with a cyanide or an alkali metal halide or with a copper salt, according to the Sandmeyer, Korner-Contardi, Gattermann and Angeli reactions (see "Name Index of Organic Reactions", Gowan J.E. & Wheeler T.S., 1960, Longmans).

The products obtained from all the reactions just described will be 3-aminophenylureas substituted at the phenyl ring, in the form of a base or an acid addition salt, which can be transformed, respectively, into an acid addition salt, a salt of another acid, or a base, by reaction with an acid, an acid salt, or a base, for example, in solution or on an ion-exchange column. Thus, the reaction of an acid addition salt with an alkali such as sodium hydroxide gives 3-aminophenylurea substituted at the phenyl ring, in the base state.

- 14 -

For the treatment or prophylaxis of malaria, compounds of formula I may be presented as pharmaceutical preparations, with a vehicle for pharmaceutical uses, compatible with the other materials of the preparation. This vehicle may be a solid or liquid material, and the preparation will preferably be in unit dose form, for example, in tablet form. Such preparations may also include other substances having pharmacological activity. These preparations may include amidinoureas of formula I.

either in base form or as a salt added to an acid, and they can be obtained using all the usual pharmaceutical techniques, which essentially consist of mixing the various materials. 15 For oral administration, fine powders or granules of the active compounds can be prepared, which may contain diluents and dispersants as well as surfactants, and they can be presented as a potion in water or syrup, in capsules or dry tablets, or suspended in an aqueous or non-aqueous medium, possibly with a suspending agent, in tablets, preferably made with granules of the active substance and a diluent, by compression with binding and lubricating agents, or suspended in water or in a syrup or oil or in a water/oil emulsion,

It may contain perfumes, preservatives, lifting/suspending agents, thickeners, and emulsifiers. The granules or tablets may be coated, and the tablets may be scored.

1

- 15 -

For administration by the parenteral route, the active compounds may be presented in unit doses or in packages containing several doses, as injectable solutions, aqueous or non-aqueous, which may contain antioxidants, buffers, bacteriostatic agents and solutes which make the compounds isotonic with blood, as aqueous or non-aqueous suspension, possibly with suspending agents and thickeners; extemporaneous injectable solutions or suspensions may be prepared from sterile powders or granules or tablets, which may contain diluents, dispersants and surfactants, binders and lubricants.

Based on trials with formula I compounds to treat experimental malaria infections in laboratory animals, it is estimated that a dose of 1 to 100 mg/kg may constitute a therapeutic dose in humans, but naturally, it is not possible to predict doses accurately due to differences in sensitivity between the host and the parasite, in experimental animals and in humans.

The present invention thus comprises the compounds of formula I, as well as their acid addition salts and their preparation. It is understood that it does not relate to the substances described when used therapeutically.

The following examples are given only to describe this invention in more detail, but they do not limit its scope in any way. All temperatures are given in degrees Celsius.

-1 6~

EXAMPLE 1:

Heat under reflux for 30 minutes

6.1 g of 4-chloro-3-cyano-aniline with 3.7 g of dicyanodiamide, 16 ml of water and 3.6 ml of concentrated hydrochloric acid.

The salt is collected by filtration and washed with a little water, then dried and recrystallized in alcohol. The hydrochloride of 4-chloro-3-cyanophenylbiguanide crystallizes as white needles (6.4 g) that melt at 233°C with effervescing. The base is obtained in the form of small white needles by alkalinizing the solution of this salt with sodium hydroxide. By recrystallization in alcohol, this base forms colorless prisms that melt at 202°C with effervescing. 3.2 g of this biguanide base is dissolved in

32 ml of ethanesulfonic acid is maintained at 90°C for 2 hours; it separates into colorless crystals of ethanesulfonate of l-amidino-3-(4-chloro-3-cyanophenyl)urea. After cooling, 2.8 g of this salt is collected and recrystallized in methanol or water, yielding white needles that melt at 219°C. The base is obtained by treating an aqueous solution of this salt with sodium hydroxide. The base forms white needles that melt at 222°C, which can be further purified by recrystallization in alcohol. This substance is weakly so-

In example 1, 3-chloro-4-cyanoaniline is converted into 3-chloro-4-cyanophenylbiguanide hydrochloride, which forms

5. By cooling, it crystallizes a hydrochloride, which is lubricated in water.

EXAMPLE 2:

In the manner just described in

By crystallization in methanol, white, felt-like needles form, with a melting point of 258°C and effervescence. The corresponding base forms white prisms in alcohol, with a melting point of 181°C.

Five grams of the biguanide are dissolved in 100 ml of half-normal ethanesulfonic acid, and the solution is maintained at 90°C for 2 hours. After cooling, a high yield of 3-amidino-(3-chloro-4-cyanophenyl)urea ethanesulfonate is obtained, which crystallizes in white prisms with a melting point of 224°C. The corresponding base, after crystallization in alcohol, melts at 213°C.

EXAMPLE 3:

Six g of dichloramine T are added to a solution of 5.9 g of 4-cyanoaniline in 59 mL of chloroform. After 4 hours, the solution is filtered, evaporated, and the remaining material is leached with normal sodium hydroxide. The undissolved crystallized material (6 g) is 2-chloro-4-cyanoaniline, with a melting point of 99–100°C; after recrystallization in aqueous alcohol, this material melts at 102°C.

4.2 g of 2-chloro-4-cyanoaniline is heated under reflux for 15 minutes with 7.5 g of dicyanodiamide, 6.6 mL of concentrated hydrochloric acid, and 15 mL of water. The crude hydrochloride formed, which crystallizes upon cooling, is then separated, dried, and heated with alcohol. The remaining 4.1 g of 2-chloro-4-cyanophenylbiguanide hydrochloride melts at 243°C with effervescing and, after recrystallization in water, melts at 244°C. The corresponding base forms white needles that melt at 193°C with effervescing.

-1 8-

By maintaining a temperature of 90° for 3 hours,

5 Ç

normal c 6

solution of 3.5 g of biguanide in 35 ml of ethane-

Normal suifonic acid/then upon cooling, 4.4 g of ethanesulfonate of l-amidino-3-(2-chloro-4-cyanophenyl)urea separates in the form of colorless prisms melting at 211-214° and recrystallization in methanol leads to a product that melts at 214°. The corresponding base forms white needles, melting point 210° with effervescence.

EXAMPLE 4:

10. In the manner described in example 1, 2-bromo-4-cyanoaniline is transformed into 2-bromo-4-cyanophenylbiguanide hydrochloride, melting point 234°C (the corresponding base, which forms white needles, melts at 200°C). This biguanide is converted in the manner described

15 in example 3, in ethanesulfonate of l-amidino-3-(2-bromo-4-cyanophenyl)urea, white prisms with pji-tic=of methanol,

Melting point 210°. The corresponding base forms white needles that melt at 206° while efferving.

EXAMPLE 5:

20. In the manner described in Example 1, 4-cyano-3-methylaniline is converted into 4-cyano-3-methylbiguanide hydrochloride, melting point 232° after recrystallization in water (the corresponding base melts at 172°).

after recrystallization in alcohol). In the manner described in Example 1, this biguanide is converted to ethanesulfonate of l-amidino-3-(4-cyano-3-methylphenyl)urea, white prisms from water, melting point 232° (the corresponding base forms white flakes after crystallization in water, melting point 200.5°).

EXAMPLE 6:

As described in Example 1, 4-Cyano-2-methylaniline is converted to 4-Cyano-2-methylphenylbiguanide hydrochloride, which separates from aqueous solution into white needles melting at 256°C (the corresponding base forms white prisms from an alcoholic solution, melting point 183°C with effervescence). This biguanide is then converted, as described in Example 1, into 1-Amidino-3-(4-Cyano-2-methylphenyl)urea ethanesulfonate, which crystallizes in methanol as white needles, melting point 204°C. The corresponding base forms white needles from aqueous solution, melting point 171°C.

EXAMPLE 7:

To a solution of 5.9 g of 4-cyanoaniline in 60 ml of acetone, 5.3 g of anhydrous sodium carbonate and 5.5 g of ethyl chloroformate are added. The mixture is then heated under reflux for 3 hours and filtered. The filtrate is evaporated to dryness, and the remaining material is crystallized in aqueous alcohol, yielding 7.4 g of p-cyanophenylurethane, in pale yellow prisms melting at 115.5°C.

2.9 g of guanidine hydrochloride are added to a solution of 0.7 g of sodium in 60 mL of ethanol, followed by 4.9 g of p-cyanophenylurethane, and the mixture is heated under reflux for 4 hours. The mixture is hot-filtered, the filtrate is evaporated, and the remaining material is leached with aqueous alcohol (20 mL of alcohol and 10 mL of water). The remaining insoluble crystallized material, i.e., 1.5 g of crude l-amidino-3-p-cyanophenylurethane (melting point approximately 199°C), is purified by recrystallization.

-20-

normal,

in ethanesulfonic acid/ in the form of ethanesulfonate, melting point 219-220°, identical to the product described in example 9.

EXAMPLE 8:

In the manner described in Example 1, 3,4-Dichloroaniline is converted to 3,4-Dichlorophenylbiguanide hydrochloride, which forms white needles, melting at 230°C, from an aqueous solution (the corresponding base forms white flakes from an alcoholic solution, melting point 154°C). This biguanide is then converted, in the manner described in Example 1, to l-Amidino-3-(3,4-Dichlorophenyl)urea ethanesulfonate, which forms white prisms from an aqueous solution, melting point 224°C. The corresponding base forms hydrated white needles from an aqueous solution, melting point 95-98°C.

EXAMPLE 9:

11.8 g of p-cyanoaniline is dissolved in 50 mL of dinormal hydrochloric acid at 90°C. While stirring, 8.4 g of dicyanodiamide is added, and the mixture is heated under reflux for 30 minutes. The p-cyanophenylbiguanide hydrochloride formed separates during this time. After cooling, 20 g of this salt is collected and washed with water; it melts at 277°C, decomposing.

By subjecting this salt to metathesis with silver ethanesulfonate in aqueous solution, a solution of p-cyanophenylbiguanide ethanesulfonate is obtained, the evaporation of which leaves the salt in a crystalline state. Recrystallization in alcohol gives white flakes.

-21 —

melting point 209-211°.

A solution of 13.5 g of p-cyanophenylbiguanide ethanesulfonate in 120 ml of ethanesulfonic acid, at room temperature, slowly deposits 5 colorless prisms of l-amidino-3- ethanesulfonate.

(cyanophenyl)urea, which melt at 218-219°C while efferving. A yield of 50% is obtained in 7 days, but

After a longer period of time, the yield rises to 80%.

A solution of this ethane-10 sulfonate is alkalinized in hot water with sodium hydroxide ION. The base formed crystallizes into white prismatic needles, melting point 205°C with effervescence.

A solution of 10 g of p-cyanophenylbiguanide ethanesulfonate in 500 mL of ethanesulfonic acid is treated dropwise with a concentrated aqueous solution of 20 g of sodium nitrite. The flocculent precipitate that initially forms redissolves, and effervescence is observed, followed by precipitation. After two hours, the solid material formed is collected and washed with cold water, then dissolved in hot water, and sodium hydroxide ION is added to the solution. The resulting 3-(4-cyanophenyl)amide urea separates into prismatic needles with a rather altered color, a melting point of 205°C, and effervescence.

25 EXAMPLES 10 and 11:

L-Amidino-3-(2-chloro-4-cyanophenyl)urea ethanesulfonate tablets are prepared using the following materials:

-22-

Example 11 Example 12

Ethane-sulfonate of 1*amidino-

Urea 100 mg 200 mg Lactose B.P. (British Pharmacopoeia) 125 mg 100 mg

Starch B.P. 60 mg 75 mg

Magnesium stearate B;P. 5mg 10mg.

• The tablets of example 10 are prepared by wet granulation and compression, with a 10% gelatin solution as the granulation agent, while those of example 11 are prepared with an alcoholic solution of polyvinylpyrrolidone.

EXAMPLE 12 t

7.92 g of p-aminobenzenyl fluoride hydrochloride is heated under reflux for 15 minutes with 10.08 g of dicyanodiamide, 7.04 mL of concentrated hydrochloric acid, and 20 mL of water. The solution is then cooled and alkalinized. The base separates as an oily substance that solidifies slowly and is extracted with ether. The extract is dried over anhydrous sodium sulfate, evaporated, and the remaining material is heated to 90°C in normal solution in 100 mL of ethanesulfonic acid. After two hours, the reaction mixture is cooled, and 6.5 g of crystallized product is collected. Recrystallization in methanol gives l-amidino-3-p-trifluoromethyl-phenyl-urea ethanesulfonate, melting point 222°, in the form of white prisms. The base crystallizes in water as white flakes which melt at 173°.

EXAMPLE 13:

Heat under reflux for 15 minutes.

-23-

6.8 g of 4-chloro-3-nitroaniline with 5.04 g of dicyanodiamide and 15 mL of 4N hydrochloric acid are reacted. The reaction mixture is then filtered while still hot to separate a small amount of residual material. The filtrate is then alkalilated, and the crude basic material that separates is collected and leached with cold 0.2N acetic acid, using a total of 300 mL of acetic acid. The remaining insoluble material (2.3 g) is crystallized in alcohol, yielding buff-colored prisms of slightly soluble 3-amidino-(4-chloro-3-nitrophenyl)urea acetate, with a melting point of 175.5°C and effervescing. The acetic extract is alkalinized, and the precipitating base is crystallized in aqueous alcohol, yielding 6.5 g of brown prisms of 1-(4-chloro-3-nitro)phenyl biguanide, melting point 164°. This biguanide is converted, as described in Example 1, to 1-amidino-3-(4-chloro-3-nitrophenyl)urea ethanesulfonate, which crystallizes in methanol as pale yellow prisms, melting point 214-215°. The base crystallizes in alcohol as yellow needles that melt at 20 to 213° with effervescing.

EXAMPLE 14:

22.5 g of 2-chloro-5-nitrobenzenyl fluoride (J. Org. Chem., 1957, 22, 300) is added dropwise, while stirring, to a solution of 67.8 g of dehydrated stannous chloride in 325 ml of ethanol and 60 ml of concentrated hydrochloric acid. After this addition, the solution is heated for 30 minutes in a water bath. The alcohol is removed by distillation, and the remaining material is poured into an excess of sodium hydroxide. The resulting basic oily substance is collected in ether and dried.

-24*-

over anhydrous sodium sulfate and distilled. This yields 4-chloro-3-trifluoromethylaniline, boiling point 118-120°C

17th

under 17 mm of mercury, refractive index n = 1.5150.

D

This product crystallizes and melts at 38-39°.

5.9 g of this aniline is heated for 15 minutes under reflux with 5.5 g of dicyanodiamide and 15 mL of 4N hydrochloric acid. Upon cooling, 6 g of a crystalline hydrochloride separates, which, upon recrystallization in water, yields white flakes of 4-chloro-3-trifluoromethylphenylbiguanide hydrochloride, melting point 210-211°C. A 3.5 g solution of the base corresponding to this hydrochloride is heated to 95°C in normal methanesulfonic acid: after 25 minutes, crystals begin to separate. After 2.5 hours, the reaction mixture is cooled, the crude product is collected, and it is recrystallized in methanol. L-amidino-3-(4-chloro-3-trifluoromethyl)phenyl-urea methane-suifonate crystallizes into white needles that melt at 239-240°C as they decompose.

EXAMPLE 15:

15.2 g of 3-chloro-4-cyanoaniline is heated under reflux with 16.8 g of dicyanodiamide and 50 mL of 4N hydrochloric acid until a solid begins to separate. The reaction mixture is then maintained at 100°C for 30 minutes, cooled, and filtered. The solid is dried, heated with 200 mL of alcohol, and after cooling, 23 g of the remaining solid is collected, washed with alcohol, and dried. This substance, which constitutes the hydrochloride of 3-chloro-4-cyanophenylbiguanide, melts at 257-258°C, decomposing. It is dissolved

-25-

in 300 ml of boiling water and the solution is alkalinized with sodium hydroxide 1CN. After cooling, the biguanide base is collected and washed with water, melting point 174-175° with effervescence; this compound is sufficiently pure to be used in the next operation.

16.4 g of this base is dissolved in 164 ml of ethanesulfonic acid. The solution is maintained for hours at a temperature of 100°C and then cooled. This yields ethanesulfonate of l-amidino-3-(3-chloro-4-10 cyanophenyl)urea in a crystalline state, which melts at 223-224°C with effervescing. Recrystallization in water or methanol gives colorless prisms, which melt and decompose in a similar manner. This salt is dissolved in hot water and the solution is alkalinized with sodium hydroxide (1CN). The base, which separates into white flakes, melting point 212-213°C with effervescing, undergoes little change following recrystallization in alcohol. EXAMPLE 16:

1.52 g of 3-chloro-4-cyanoaniline is heated for two hours at 100°C with 0.84 g of dicyanodiamide and 20 ml of ethanesulfonic acid. After cooling, the solid product is collected by filtration, dried, and then heated with alcohol. After cooling, the remaining insoluble solid matter is collected and washed with alcohol. The remaining crystallized matter, which melts at 223°C and decomposes, is identical to the ethanesulfonate of Example 2.

If we replace N-ethanesulfonic acid with Nr-methanesulfonic acid, we obtain the corresponding methanesulfonate 30, which melts at 249-250°C while decomposing.

Q

-26-

EXAMPLE 17:

1.52 g of 3-chloro-4-cyanoaniline is heated under reflux for 15 minutes with 1.68 g of dicyanodiamide and 30 ml of normal hydrochloric acid. A small amount of bleaching charcoal is added, and the mixture is then filtered at boiling point. The filtrate yields white needles of l-amidino-3-(3-chloro-4-cyanophenyl)urea hydrochloride, which decompose at approximately 250°C.

Cn obtains the same product by heating 3-chloro-4-cyanophenyl-biguanide for a short time under reflux, with dilute hydrochloric acid.

EXAMPLE 18:

1.74 g of 1-amidino-3-(3-chloro-4-cyanophenyl)urea ethanesulfonate is dissolved in 150 mL of boiling ethanol, and a solution of 1.08 g of dry sodium embonate in 50 mL of methanol and 50 mL of water is added to this solution. The solution is heated under reflux, and the 1-amidino-3-(3-chloro-4-cyanophenyl)urea embonate crystallizes rapidly. This salt is collected by filtration and washed with water. It melts at 195°C with effervescing.

EXAMPLE 19:

Urethane, i.e., methyl 3-chloro-4-cyanophenyl carbamate (melting point 136°C), is prepared from 3-chloro-4-cyanoaniline according to the method in Example 7. 4.5 g of this substance is heated for 4 hours under reflux with an ethanolic solution of guanidine (obtained from 2.5 g of hydrochloride). Cooling yields 0.5 g of crystalline solid, and evaporation provides a further 0.9 g of this material. This crude base is purified by dissolving

-27-

in the calculated quantity of hot aqueous ethanesulfonic acid. It separates by cooling ethanesulfonate from 1-amidino-3-(3-chloro-4-cyanophenyl)urea, which melts at 223-224°C upon decomposition and from which free base 5, melting point 211.5°C upon decomposition, can be obtained. These products are identical to those of Example 15.

EXAMPLE 20:

9.8 g of 2,4,5-trichloroaniline is heated with 8.4 g of dicyano-diamide and 50 ml of 4N 10 hydrochloric acid for two hours in a bath at a temperature of 100°C, then the mixture is subjected to steam distillation to remove the trichloroaniline that has remained unaltered.

remaining ex

The liquid is then treated in the distillation flask with activated carbon and then alkalized with hydroxide.

15 of sodium ION, which precipitates the l-amid.ino-3-(&.4.5-tri-

chlorophenyl urea in its crude state, which is purified to the methanesulfonate state by crystallization in the quantity

calculated from dilute aqueous methanesulfonic acid. This salt forms white, silky needles that begin to decompose

20. Place at approximately 236°. The free base, crystallized in aqueous alcohol, forms white and silky needles of a monohydrate, melting point 180.5° with effervescence.

EXAMPLE 21 Î

A mixture of 6.18 g of 4-nitro-3-trifluoromethylaniline is heated under reflux for 10 minutes.

7.54 g of dicyanodiamide and 22.5 mL of 4N hydrochloric acid are mixed to obtain a clear solution, which is then alkanilized with sodium hydroxide ION. The precipitate is collected and washed with water, then the crude base is extracted with 30-50 mL of hot dibasic acetic acid and the extract is alkanilized.

-28-

with sodium hydroxide ION, which precipitates 4-nitro-3-trifluoromethyl-biguBnide. Upon crystallization in alcohol, this compound forms orange prisms that melt at 149-150°C.

The reaction of this biguanide (4.8 g) with normal methanesulfonic acid, according to the method of Example 14, gives l-amidino-3-(4-nitro-3-trifluoromethylphenyl)urea methanesulfonate in yellow needles that melt at 245°C and decompose. The free base, by crystallization in aqueous alcohol, forms pale yellow, silky needles that melt at 202°C with effervescing.

EXAMPLE 22:

The process described in Example 15 is applied to 4-cyano-3-fluoroaniline (US Patent Application No. 522,817). The biguanide hydrochloride that separates from the reaction mixture melts at 274°C by decomposing, while the free base forms white platelets that melt at 169.5°C by efferving.

L-amidino-3-(4-cyano-3-fluorophenyl)urea methane-suifonate crystallizes in water into white prisms 20 which melt at 241-242° with effervescence, while the corresponding free base melts at 205-206° also with effervescence.

EXAMPLE 23:

The process of Example 21 25 is applied to 3-chloro-4-nitroaniline. The biguanide formed crystallizes in alcohol as yellow flakes, melting point 178°, and the methanesulfonate of l-amidino-3-(3-chloro-4-nitrophenyl)urea crystallizes in water as yellow prisms that melt at 241°.

by decomposing.

-29-

EXAMPLE 24:

A guanidine solution is prepared by reacting a sodium ethoxide solution in 15 mL of ethanol with an equivalent of guanidine hydrochloride (2.1 g). After separating the sodium chloride by filtration, 4.1 g of l-(3,4-dichlorophenyl)urea is added and the solution is evaporated to dryness. The remaining material is heated for three hours in a bath at a temperature of 130°C, during which time ammonia is released. The residue is then extracted with hot decinormal ethanesulfonic acid and the extract is alkalinized, causing the separation of white, woolly crystals of l-amidino-3-(3,4-dichlorophenyl)urea. Recrystallization in aqueous alcohol gives the hydrate, melting point 95–98°C (alone or in mixture with the

/v _ according to the fusion points produced in example 8). This identity of the two products is confirmed by thin layer chromatography, with silica gel.

EXAMPLE 25:

A guanidine solution is prepared by reacting a sodium ethoxide solution in 15 ml of ethanol with an equivalent of guanidine hydrochloride (2.1 g).

After separating the sodium chloride by filtration, 5.2 g of 1-(3,4-dichlorophenyl)-3,3-diethylurea is added and the solution is evaporated to dryness. The residue is heated for 2.5 hours in a bath at 120°C, with diethylamine being released in its free form. The molten mass is extracted with 200 mL of hot decinormal ethanesulfonic acid, in which most of the material dissolves and, upon cooling, separates into white needles of 1-amidino-30 3-(3,4-dichlorophenyl)urea, one of which is recrystallized in

—30—

Ethanol gives white prisms that melt at 222° and whose melting point is not lowered after mixing with the corresponding product of example 8.

EXAMPLE 26:

phenyl, melting point 84-86°, from 3-chloro-4-cyanoaniline, according to the method described in J. Amer. Chem. Soc., 1938, 60, 2675, then a solution of 7 g of this isocyanate in 50 ml of anhydrous dioxane is treated, drop by drop and while stirring, with a solution of 2.75 g of diethylamine in 25 ml of anhydrous dioxane. The solution is stirred for a further 30 minutes after the addition is complete, then evaporated to dryness and the remaining material crystallized in aqueous alcohol, giving 8.4 g of fawn-colored flakes, melting point 110-111°, of 1-(3-chloro-4-cyanophenyl)-3-,3-diethylurea.

Guanidine base, following the method of Example 24, yields crude ethanesulfonate of l-amidino-3-(3-chloro-4-20 cyanophenyl)urea. Recrystallization in methanol provides characteristic crystals of this salt, which melt at 223-224°C and whose melting point is not lowered after mixing with the corresponding product of Example 15.

EXAMPLE 27:

25. Add 0.75 g of thinly sliced sodium to 40 ml of acetone and treat the resulting hot suspension with 4.43 g of guanidine thiocyanate. Then add 5.1 g of 3,4-dichlorophenyl isothiocyanate. Heat the mixture under reflux for 5 minutes and pour it onto ice. 30. Collect the precipitate and...

5

We prepare 3-chloro-4-cyano- isocyanate

We react 5.3 g of this urea with the

!

-31 ~

crystallizes in methanol, yielding 2.8 g of colorless pellets that melt at 168.5°C with a lively effervescence.

One g of this substance, which is 1-amidino-3-(3.4-dichlorophenyl)thiourea, in solution in 20 ml of 5-methanol, with 1 ml of methyl iodide, is heated under reflux for 30 minutes.

Evaporation of the solution and the addition of alkali precipitates 1-amidino-3-(3,4-dichlorophenyl)-S-methylisothiourea, which, upon crystallization in methanol, forms colorless orthorhombic crystals that melt at 165-166°C with effervescence. 600 mg of this substance is added, in several stages, to 100-volume hydrogen peroxide, and when the vigorous reaction has ceased, the product is collected and dissolved in boiling water, leaving a slight residue. The addition of alkali to this solution precipitates 1-amidino-3-(3,4-dichlorophenyl)-15-urea, which is characterized by ethanesulfonate, melting point 223-224°C with effervescence, identical to the product of Example 8.

EXAMPLE 28:

20 with thiophosgene gives, with good yield, the iso-

3-chloro-4-cyanophenyl thiocyanate which crystallizes in cyclohexane in tawny-colored prisms, melting point 77.5° and which is converted according to the method of example 27f successively into l-amidino-3-(3-chloro-4-cyanophenyl)thiourea, 25 white primers melting at 199.5° with effervescence then into l-amidino-3-(3-chloro-4-cyanophenyl)-S-methyl-iso-thiourea,

white needles melting at 165° with effervescence. This latter substance is likewise oxidized by means of hydrogen peroxide, which gives l-amidino-3-(3-chloro-4-cyanophenyl)urea, melting point 212° with effervescence, identical to the product of example 15.

The reaction of 3-chloro-4-cyanoaniline

-32-

EXAMPLE 29:

Ten mL of pyridine is heated under reflux with 2.5 mL of 4N hydrochloric acid and 10 mL of benzene in a Dean-Stark apparatus until no more water is collected. The benzene is then removed by distillation, and 1.52 g of 3-chloro-4-cyanoaniline and 0.92 g of dicyanodiamide are added to the remaining material. The mixture is heated under reflux for 2.5 hours, during which time a solid separates. This solid is separated by filtration after cooling and washed with alcohol. This solid, which is 3-chloro-4-cyanophenylbiguanide hydrochloride, melts at 258°C. The corresponding base is transformed into l-amidino-3-(3-chloro~4-cyano-phenyl)urea ethanesulfonate according to the method of example 15.

15 EXAMPLE 30 i

To prepare the solution, 6.2 g of 1-amidino-3-(3-chloro-4-nitrophenyl)urea methanesulfonate (example 23) is heated with 13.6 g of crystallized stannous chloride and 54 mL of normal hydrochloric acid. The crude dihydrochloride of 1-amidino-3-(4-amino-3-chlorophenyl)urea separates upon cooling. Recrystallization in water forms white flakes (2.7 g) that begin to decompose at around 200°C and turn black at 220°C. A solution of 0.45 g of this salt in 12.5 ml of water is dissolved with 0.11 g of sodium nitrite, and the resulting solution is added to a 95° solution prepared with 0.4 g of crystallized oleoresin sulfate, 0.5 g of potassium cyanide, and 5 ml of water. When the effervescence has ceased, i.e., after 30 minutes, the reaction mixture is cooled and filtered, and the solid matter is extracted with

-33-

Hot water is added, and the extract is alkalized. The brownish base that precipitates behaves like l-amidino-3-(3-chloro-4-cyanophenyl)urea on a thin-film electromatogram, showing a spot with characteristic blue fluorescence under ultraviolet light and not giving a colored reaction with Ehrlich's reagents. This base is purified to the ethanesulfonate state, melting point 224°.

EXAMPLE 31:

10 phenyl with 1.5 g of thiourea and heat the mixture to

100° for 3 hours, then the product is crystallized/formed.

in methanol, in which it produces white needles

(2.5 g) which melt at 219° with effervescence, of l-(3.4-di-

chlorophenyl)-4-thio-biuret. 1 g of this is heated under reflux.

15 substances with 25 ml of methanol and 1 ml of methyl iodide,

until a clear solution is formed, which is then concentrated at

half its volume and which is added to 10 ml of a methanolic solution/

The solution is saturated with ammonia. After 48 hours, the solution is evaporated and the remaining gummy material is extracted with 20 decinormal ethanesulfonic acid. The extract is then concentrated and allowed to crystallize. The first quantity of material collected, which melts at 217-219°C with effervescence, is recrystallized in ethanol. This yields colorless tablets, melting at 223-224°C with effervescence, of ethane-25 sulfonate of l-amidino-3-(3,4-dichlorophenyl)urea.

EXAMPLE 32:

After adding acetone, 3.5 g of guanidine thiocyanate is added to the resulting suspension, and then 3.75 g of 3,4-30 dichlorophenyl isocyanate is added, while shaking, to the clear solution formed.

3.7 g of 3,4-dichloro- isocyanate are mixed

solid/

Dissolve 0.7 g of sodium in 40 ml

-34-

After 1 hour, the solution is poured into water. An amorphous precipitate forms, which is separated and extracted with 200 ml of decinormal ethanesulfonic acid, but a significant amount remains insoluble. The extract is concentrated to a small volume until a crystalline crude product separates. Recrystallization of this product in ethanol yields colorless tablets of α-amidino-3-(3,4-dichlorophenyl)urea ethanesulfonate, melting point 223-224°C.

Claims (1)

- 35 - SUMMARY The present invention includes in particular: 1) As novel industrial products, amidinoureas of formula I NH y4-0,NH-co-NH,c ( i ) •NH2 Y as well as their acid addition salts, a formula in which 4 > 10 Y is a halogen and Y is a trihalomethyl group, nitrile or nitro in position 3 or a halogen in position 3 or both in positions 1 and 5 or 4 > j Y is a trihalomethyl or nitrile group and Y is a hydrogen atom or a halogen or an alkyl group having 15 of 1 to 4 carbon atoms in position 2 or 3, or 4 Y is a nitro group and Y is a trihalomethyl group or a halogen in position 3. 2°) A process for preparing the products specified under 1°, comprising one of the following variants: 20 (A) the oxygen atom of the carbonyl group is introduced into a compound of formula II NH (II) y4^r_\_NH-C = N - C ^ X " NH9 , Y 25 instead of the X reactive group, or (B) Guanidine is reacted with a derivative reagent of a phenylcarbamic acid of formula III . 0 Y4-/~WC ^ (III) ^ OH - 36 - or 4 (C) An aniline Y.Y or a reactive derivative thereof is reacted with a reactive derivative of a guanidine-carboxylic acid of formula IV 5 NH II HOOC-NH-C - NP^ (IV) or (D) a methylene urea of formula V is subjected to aminolysis R 10 Y4 M. -NH-CO-N = (V) M*7 R- Y in which R and R' are reactive substituents, or (E) a diazepatic L-amidino-3-(aminophenyl)-urea is reacted with a cyanide or a halide of an alkali metal 15 or with a copper salt to form an amidinourea of 4 formula I, in which at least one of the symbols Y and Y represents a halogen atom or a nitrile group, as appropriate. 3°) Methods of execution of the process specified under 2°, 20 exhibiting the following characteristics? taken separately or according to the various possible combinations; 4 a) Y is a nitrile or trifluoromethyl group and Y is a hydrogen atom or a halogen atom in position 4 2 or 3, or Y is a halogen atom and Y is a nitrile or nitro group, a halogen or a trifluoromethyl group in position 3; b) Y4 or a halogen atom in position 2 or 3; c) Y4 is a halogen atom and Y is a halogen atom 30 or a nitrile or nitro group in position 3 4 b) Y is a nitrile group and Y is a hydrogen atom - 38 - >s o) aniline is 3-chloro-4-cyano-aniline; formula V 4 p) methyleneurea is a 1-(Y .Y-phenyl)-4-thio- biuret substituted on the sulfur atom, in particular by an alkyl group, more particularly an S-alkyl -(in particular methyl)-l-(3-chloro-4-cyanophenyl)-4-thiobiuret; q) the .thiobiuret is treated with an alcoholic solution of ammonia; r) in methyleneurea, R and R' are both alkoxy groups or R' is an amino group and R is an aryloxy or aralkoxy group; s) in methyleneurea, Y4 is a nitrile group and Y is a chlorine atom in position 3. 4°) As new industrial products, biguanides of formula NH Y^/^Vnh-C-NH-C ^ NH NH2 Y as well as their salts of addition to acids, formula in which: Y4 represents a halogen atom and Y a trihalomethyl or nitrile group in position 3, or a halogen in positions f1 and 5, or 4 Y is a trihalomethyl or nitrile subgroup and Y is a halogen atom or an alkyl group having 1 to 4 carbon atoms in position 2 or 3, or 4 Y is a nitro group and Y is a trihalomethyl group or a halogen in position 3. in particular 4-chloro-3-trifluoromethyl-phenylbiguanide and 4-cyano-3-methyl-phenylbiguanide and their addition salts to the acids "José CURAO ORIGINAL Industrial Property Consultant 28, BouL Mik»sm Charlotte, 28 „ containing Rem'--US MONTE CARLO By procumik»«