CA1174241A - Derivatives of pyrrole for protecting the myocardium, having an antiarrhythmic activity and an activity as blood platelet anti-aggregant, process for preparation thereof and drugs containing same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The present invention relates to new derivatives of pyrrole of formula:

(I) in which:
-R1 represents an atom of hydrogen, a lower alkyl group, a phenyl radical or a pyridyl-2 radical, -R2 represents an atom of hydrogen or a lower alkyl radical -R3 and R4 represent a lower alkyl or cycloalkyl radical or the radical is a heterocyclic amine radical, and -n is equal to 2 or 3;
the invention concerns drugs having an antiarrhythmic activi-ty and an activity as blood platelet anti-aggregant, containing said derivatives.

Description

~7~

The present invention relates, as new industrial products, to derivatives of pyrrole, as well as to the methods for preparing them and application thereto in therapeutics.

The novel com~ounds according to the invention correspond to the general formula:

_ \ 1 1 /~3 ~ C (CH2)n--N ~ (I) =<~ R4 R2.

in which:

- Rl represents an atom of hydrogen, a lower ~lkyl group, a phenyl radical or a pyridyl-2 radical;
- R2 designates an atom of hydrogen or a lower alkyl radical;
- R3 and R~, which are identical or different, each represent a ~er alkyl or cyclc>alkyl radical or the group - N ~ R3 design~es a cyclic amine radical csmprising 1 or 2 cycles an~ being able to posse~s a second heteroatom and comprise substi-tuents; and - n is equal to 2 or 3.
'~

~74;~41

-2-~R3 When the group - N is a cyclic amlne radical, the follo~ving rr~ay be mentioned among said amines:
pyrrolidine, piperidine, dimethyl-2J 6 piperidine, morpholine, piperazine and the radical S . r~
_ N N

In the present invention, lower alkyl group designates straight or branched alkyl groups having from l to 6 atoms of carbon.

The compounds tI) yield soluble salts with the mineral or organic acid~. These salts, with the pharmaceu-tically acceptable acids, form an integral part of the inven-ti~n According to the nature of the substituent Rl, the compounds ~I) may be obtairled by one of the following methods:

When Rl designates hydrogen, the compounds (I) may be obtained according to two ~rocesses.

-3.- ~L17~4~

Method A

The dlfferent steps of the process are Indicated in the following reaction diagram:
. COOC2 H5 CM3CONH C ~ (CH2)n~N ~ H2N--CH --(CH ) -N
t COOC2H5 `~ H2N -- CH--(CH2)2-N~ ~ ~2N -- CH--tCH2)2-N/~

- -~\ H /R3 _~ N--C--(C}t2 )n -N~ (P~l = H) \ R2 CO~lH2 4 The compound 1 is prepared by alkylation according to the known processes of ethyl ~o~arnidomalonate, By sapo-nification of the compound 1 in an alkaline medium, the corres~
ponding malonic acid is obtained which easily decarboxlates by heating in an acid medium to yield the substituted butyric acid Z. The latber is esterified by a known process into methyl ester 3. The ester 3 is converted into the correspcn ding amide 4 by action of ammonia according to a known process~ Finally~ the amide 4 is converted into compound (I) by heating with a y-diketone R2C-CH2CH2C-Rz in the acetic acid, O O

_4_ ~7~

In the particular case of R2 = H, compound (I) may be obtained by heating the amide 4 with dimethoxy-2, 5 tetrahydrofuran in absolute alcohol in the presence of acetic acid 5Method A

The different steps of the process are indicated in the following reaction diagram:

/~ H
Br (CH2)n-CH--COOCH3, HC1 ~ ~ , ( 2)n ~_ ~\ H ~ 3~ H ~ 3 ~CH2)n N~ R ) ~ N--C-- (CH2) -N
~::~< COOCH3 4 ~ CONH2 4 7 (I) ~Rl = H) The hydrochlori~de of methyl amino-2 bromo-4 butyrate 5 ~Tetrahedron, 25, 5971-81, ~1969) ~ is converted into corresponding pyrrolic derivative either by action of a y'-diketone, or by action of the dimethoxy-2, 5 furan, as indicated in method Al.

By action of an an~lne HN~ on 6 in solution lS in an inert so1vent, such as benzene or toluene, the compound 7 is obtained which, by amidification by ammonia, leads to the products (I), (Rl = H).
Method B
When Rl representfi a phenyl group or a pyridyl-2 _ 5_ J~74;~

group, the compounds (I) are obtained according to thefollowing reaction diagram from a product 8, RlC,H-A, in which R
designates a p'nenyl or pyridyl-2 group and A designates a group derived from the acid function, namely a nitrile group -C--N or an ester group -COO-Alk ~Alk represents a methyl or ethyl group). / 2 Rl --CH --A -~ 3 ~ Cl~ ~ A

~l 2 R

,1 ~ 3 ~ Rl / 3 A 4 \ CONH2 R4 (I) (Rl = phenyl or pyridyl-2) As in the methods Al and A2, the amino compound 8 is converted into the corresponding pyrrolic compound 9 by 10 action of a r-diketone or by action of the dimethoxy-2, 5 tetrahydrofuran.
R3\
The compound 9 is alkylated by N-(CH2) -Hal (Hal designating a halogen) in an inert solvent such as toluene and in the presence of a base such as sodium hydride and yields 15 compound 10. In the latter, the group A is converted into an amide group. When A represents a nitrile group, the latter is hydrolysed for example by heating with sodium hydroxide in dilute alcoholic solution. When A designates an ester group, the latter is converted into amide by action of ammonia or, in the 20 case of voluminous amines, by action of the complex salt formed by the aluminium hydride and the ammonia in the tetra-hydrofuran.

-6~ ~7~Z4~

Method C
When Rl i9 an allcyl group, the different steps of the synthesis are shown in the following reaction diagram:
N=C N=C R3 R1 ~ CH--COOC2H5 ~RlC (CI~2)n ~R
CC2~5 4 N1~2 / 3 ~<R2 Rl / 3 CC2H5 4 L~R COOCzH54 [~ --C-- (CH2)n-N--R (I) (111 = alkyl ) S The starting product 11 i5 an Oc -isocyanoester.
The products of this type are known or may be prepared accor-ding to known processes, particularly by action of the phosgene on the corresponding d-ormylaminoester compounds.
,R3 Co}npound 11 is alkylated by Hal-(CH2)n N ~ in a suitable solvent and in the presence of an alkaline agent to lead to compound 12 The latter treated by an acid in organic s olution leads to the amine 13. The latter is converted into pyrrolic derivative ~, as has been indicated prev,ously.

:Finally, the ester function is converted into amide by action of ammonia or, pre~erably, by using the complex salt formed by the hydride of lithium-aluminium and ammonia in the tetrahydrofuran.

_7_ ~l79~2~1 The following non-limiting examples are given by way of illustration for the preparation of the compounds (I).

Method A
_ _ _ -- -- -- 1 (Dimethyl-2, 5 pyrrolyl-1)-2 diisopropylamino-4 b tyramide (CM 7753) ~
(I) Rl = H; R2 = CH3; ~3 = R4 = -CH~ 3 ;n = 2 1) Amino-2 diisopropylamino-4 burytic acid _____________________________________ The mixture of 17. 3 g of ethyl (diisopropylamino-Z
ethyl)-2 acetamidomalonate and 4. 4 g of sodium hydroxide in 300 ml of water and 150 ml of ethanol at 96 is refluxed for 3 hours. The mixture is evaporated to dryness and the residue is taken up in 200 ml of 2N hydrochloric acid; the mixture is refluxed for 5 hours.

~fter cooling, the mixture is neutralised to pH 7 by the addition of a solution o~ sodium hydroxide. The mixture is evaporated to dryness and the residue is taken up in chloro-form. The insoluble sodium chloride is filtered, the solution is dried over sodium sulfate and is evaporated to dryness The resldue constituted by a brownish solid (11. 3 g) is used as such f or the following operation.
2) Methyl amino-2 diisopropylamino-4 butyrate ____________________O~________ __ ______~
22 g of thionyl chloride are added-to 30 ml of methànol, with cooling, so as to maintain the temperature below -5C, then 37. 7 g of the acid obtained hereinabova are added in portions, always maintaining the temperature lower than -5C.
When the addition is finished, the temperature is allowed to return to ambient temperature, then the mixture is heat~ed for 2 hours at ~0C. The methanol is evaporated and the residue is taken up in the minimum of water; 500 ml of ether are added -8~ 4;~43~

and, with stirring, the aqueous phase is saturated with potas-sium carbonate. The ethereal phase is separated and the aqueous phase is re-extracted with ether. The ethereal ex-tracts are combined, dried over sodium sulfate and evaporated to dryness.

A yellow liquid remains (13 g) used as such for the following operation.
3)~mino-2 dilsoprop ylamino-4 butyramide -- -- --In an autoclave cooled by an ice bath, the solution 10 of 3 g of the preceding ester is placed in Z0 ml of absolute ethanol and a current of ammonia is bubbled therein for 1 hour.
The autoclave is closed and heated at 150C for 36 hours.

The alcohol is evaporated and the residue is taken up in water and chloroform. The organic phase is separated 15 and washed with water. The aqueous phases are evaporated to dryness and the residue is extracted with chloroform. The combined chloroform extracts are dried over sodium sulfate and evaporated to dryness.

A coloured liquid remains (1. 54 g) used v~tithout 20 purification for the following operation.

4) CM 7753 The previously obtained oil (1. 54 g) and 0. 98 g of hexanedione-2, 5 is dissolved in 40 ml of acetic acid and the rnixture is heated at 100C for 3 hours. The solvent is evapora-25 ted then alkalini~ed with diluted sodiurn hydroxi de It is extrac-ted with ether, the ethereal phase is dried over sodium sulfate and evaporated to dryness. A blackish, viscous liquid is obtain~d which is chro matographed over an alumina column, eluting by the 70:30 (vol/vol) mixture of hexane-ethyl acetate A yellowish solid (1 g~ is obtained which is recrystal-~.~.7~L2~1 lised in isopropylic ether. Finally, colourless crystals are obtained; m.p. 71-72C.

.
Method A2 (Dimethyl-2, 5 pyrrolyl)-l (diaza-l, 4 bicyclo~4, 3, 0~-nonyl-4)-4 butYramide (CM 40018) (I) Rl = H; R2 = CH3; -N~ 3 = N N-; n=2 1) methyl (dimethyl-2~ 5 pyrrolyl-1)-2 bromo-4 butyrate The mixture of 30 g of hydrochloride of methyl amino-2 bromo-4 butyrate, 17. 7 g of hexanedione-2, 5 and 10. 6 g of anhydrous sodium acetate in 500 ml of acetic acid is heated at 100C for 3 hours. The acetic acid is evaporated in vacuo, then the residue is taken up with water and ether. The ethereal layer is separated and washed successively wlth water, with a solution of sodium bicarbonate and again with water. The solution is dried over sodium sulfate, then the solvent is evaporated to dry-ness.

The residue is chrorr~atographed over a silica colurrn eluting with the 9:i (vol/vol) pentane-ethyl acetate mixture.
By evaporation, a crystallised solid is obtained which is washed with petroleum ether. Weight: 15.1 g; m. p. 79C.
2) Methyl (dimethyl-2, 5 pyrrolyl-1)-2 (diaza-l, ~ bicyclo-C4. 3 Q l-nonyl-4)-4 butyrate The mixture of 11 g of the ester obtained hereinaba~ie and 10.1 g of diaza-l, 4 bicyclo-C4. 3. Oj-nonane in 150 ml of toluene is refluxed for 48 hours. After cooling, the organic solution is washed with water, dried over sodium sulfate and the solvent is evaporated to dryness in va~uo.
The residue is chromatographed over an alumina column, eluting with the 95:5 (vol/vol) pentane-ethyl acetate mixture.

1~7~:49~

An oil (9 g) is obtained, used as such for the follo-wing operation.
3) CM ~0018 In the suspension of 1. 71 g of lithium-aluminium hydride in 100 ml of anhydrous tetrahydrofuran, a current of dry ammonia gas is bubbled until the end of precipitation. The solution of 3.19 g of the ester obtained in the preceding para-graph in 40 ml of tetrahydrofuran is then added with stirring, then the mixture is heated at 55-60C for 3 hours 30 minutes.
The mixture is cooled by an ice bath and hydrolysed by a 40%
sodium hydroxide solution. It i9 filtered and the solvent is evaporated to dryness. The residue is taken up in chloroform and water. The organic phase is separated and the aqueous phase is again extracted with chloroform. The organic extracts are l$ combined and dried over sodium sulfate. The solvent is eva-porated to dryness.

The solid residue is recrystallised in ethyl acetate (1.7 g); m.p. 166-167C.

20 Method B
_ _ _ _ .
phenyl-2 (pyrrolyl-1)-2 diisopropylamino-4 butyramide (CM 7611) (~) R1~;3; R2=Hi R3 = R4 - -CH ~
n=2 3 1) Phenyl-2 (pyrrolyl-1)-2 acetonitrile ____ _ _ _ ____ _ __ ___________ The mixture of 16. 85 g of hydrochloride of amino-2 phenyl-2 acetonitrile, 8. 2 g of molten sodium acetate and 26. 4g of dimethoxy-2. 5 tetrahydrofuran in 200 ml of acetic acid is heated at 100C for 2 hours. The acetic ~'scid is then evaporated in vacuo to dryness and the residue is taken up in ether. The 30 precipitated solid is dried without heat, then the ethereal solu-~74~4~

tion is washed with water The ethereal solution is dried over sodium sulfate and the ether is evaporated to dryness The residue is distilled under a high vacuum,b- P/
0 03 mm of mercury; 108-112C The distillate crystallises;
it is recrystallised in hexane; weight: 8 g; m. p. 51C.

2) Phenyl-2 (pyrrolyl~ 2 diisopropylamino-4 butyronitrile _ The mixture of 5.16 g of the ritrile obtained pre-viously, l. 3 g of sodium amide and S. l g of chloro-l diisopro-pylamino-2 ethane in 150 ml of toluene is heated to reflux for 2 hours. After cooling, the organic solution is extracted with a dilute solution of hydrochloric acid The acid aqueous phase is separated, is alkalinised with sodium hydroxide and extracted with ether. The ethereal solution is dried and the solvent is e-~aporated to dryness. The residue is chromatographed over a silica column, eluting by the 8:2 (vol/vol) hexane-ethyl acetate mixtur e .

6. 35 g of the expected product is obtained, used as such for the following operation~
3) CM 7611 The solution o~ 6. 07 g of the nitri le obtained pre-viously and 22. 5 g of potash in 180 ml of 96~ ethanol and 45 ml of water is heated to reflux for 5 hours.

~ fter evaporation of the alcohol, the residue i5 tal~n 25 up in water and chloroform. The organic phase i8 separated, is dried over sodium sulfate and the solvent is evaporated to dryness. The residue is chromatographed over an alumina eolumn By eluting with the 8-2 (vol/vol) hexane-ethyl acetate mixture, an impurity is eliminated then, with the 1:1 (vol/vol) 30 mixture of hexane-ethyl acetate, the expected product ls eluted.

-12- ~1742~L

By recrystallisation in isopropyl ether, colourless crystals ~re obtained (4, 5g); m, p, 103-104C.

Met1od_B_ (Pyridyl-2)-2(pyrrolyl-1)-2 diisopropylamino-4 butyramide (CM 7954) (I) R~ N; R = H; R - R - -CH ~ 3;

1) Ethyl (pyridyl-2)-2 (pyrrolyl-l)-2 acetate The mixture of 22 g of amino-2 (pyridyl-2)-2 acetate of ethyl and 32. 3 g of dimethoxy-2, 5 tetrahydrofuran in 300 ml of absolute ethanol and 150 ml of acetic acid, is heated to re1ux for 3 hours, The solvents are evaporated to dryness in vacuo and the residue is taken up in an aqueous solution of sodium bicar-bonate, The ~olution is extracted with ether and is dried over sodium sulfate The solvent is evaporated to dryness and the residue is distilled under reduced pressure;h p./0. 01 mmHg: 115-lZ2C.
The distillate crystallises, m.p. 75-76Ci weight:
11,3 g.

2) ~thyl (pyridyl-2)-2 (pyrrolyl-1)-2 diisopropylamino-4 butyrate ___ _ _ ______ ___ _____ _ __ __ _______ ___ The mixture of 15. 65 g of the preceding ester, 3. 57 g of sodium hydride and 12. 4 g of chloro-l diisopropyl-amino-2 ethane in 500 ml of anhydrous toluene is heated at 100C in an atmosphere of nitrogen, for 1 hour 30 minutes.
~ fter cooling, the solution is washed with water, dried over sodium sulfate and the solvent is evaporated to dry-ness Chromatography is carried out over an alumina column.
By eluting wlth the 95:5 (voi/vol) pentane-ethyl acetate mixture, .. .. .

~7~

17. 8 g of the expected product is obtained; m. p. 45-47C.
3) CM 7954 In the suspension of 1.14 g of double hydride of lithium-aluminium in 60 ml of anhydrous tetrahydrofuran, a stream of dry ammonia i9 bubbled until the complex has finished precipitating The solution of 7.14 g of the ester ob-tained hereinabove is added in 40 ml of tetrahydrouran and the mixture is left, with stirring, at ambient temperature for 2~ hours.

E~ydrolysis is carried out by addition of 40% solu-tion of sodium hydroxide, the insoluble matter is filtered and the tetrahydrofuran is evaporated to dryness. The residue is taken up in ether, the organic solution is washed with water, dried over sodium sulfate and evaporated to dryness. The residue is recrystallised in isopropylic ether.

Colourless crystals are obtained (3. 35 g); m. p. 128-129 C .

Metho__C Methyl-2 (pyrrolyl~ 2 diisopropylamino-4 butyramide (CM 40019) (I) Rl = CH3; R2 = H; R3 = R4 - -CH\ ; n = 2 1) ethyl Lsocyano-2 methyl-2 diisopropylamino-~ butyrate 14. 54 g oI ethyl isocyano-2 propionate and 19. 75 g of chloro-l diisopropylarnino-2 ethane are dissolved in 300 ml of anhydrous ether and 120 rnl of dimethylsulfoxide. Cooling is effected with an ice bath and a suspension of 5. 73 g of 55-~0%
sodium hydrida in 90 ml of anhydrous ether is added by frac-tions. The addition terminated, the mixture is refluxed for 2 hours. After cooling, the reaction mixture is poured in 300 ml of glacial water. The organic phase is decanted and the aqueous phase is extracted three times with ether. The organic extracts .

-14- ' ~4Z43~

are combined and washed with water. Drying is effected over sodium sulfate and the solvent is evaporat ed to dryness.

The residue is distilled under reduced pressure;
B.p / 0 7 mmHg: 102-106C; weight: 16 g.
2) Ethyl amino-2 methyl-2 dlisopropylamino-4 butyrate __ _____ _ ,.__ ___ _____ ___ ____ ___ __ In 60 ml of absolute ethanol to which 1. 57 g of water is added, hydrogen chloride is bubbled up to saturation.

The solution is cooled below -10C and 16 g of the isocyanate obtained previously dissolved in 18 ml of absolute ethanol are added, then the temperature is allowed to rise progressively up to ambient temperature and the mixture is left to stand for 20 hours at this temperature. The solvent is evaporated to dryness in vacuo and the residue is taken up in ether The ethereal solution is washed with a saturated solu-tion of potassium bicarbonate in water The aqueous phase is s eparated and extracted with ether. The ethe~eal extracts are combined, dried over potassium carbonate and the solvent is evaporated to dryness.

~n oll remains (14. 75 g) used as such for the follo-wing operation 3) Ethyl methyl-2 (pyrrolyl-1)-2 diiso propylamino-4 butyrate The mixture of 2 g of the aminoester obtained here-inabove and 2.17 g of dimethoxy-2, 5 tetrahydrofuran in 30 ml of absolute ethanol and 15 ml of acetic acid is heated to reflux or 18 hours The solvents are evaporated to dryness in vacuo and the residue is taken up in ether. The ethereal solution is washed with water, then with an aqueous solution of sodium bi-carbonate and again with water The substance is dried over sodium sulfate and the solvent is evapora~ed.to dryness. Ch~
matography is carried out on an alumina column.
By eluting with the 98:2 (vol/vol) pentane-ethyl acetate mix--15- 1~L7~

ture, l. l g of the expected product is obtained.
4) CM 40019 The modus operandi is as indicated in Example 4, paragraph 3, using the ester prepared previously and reducing the duration of reaction to 1 hour instead of 24 hours.

~y the same treatment, the expected amide is obta~ned ~ith a yield of 60%;m. p. 79-80C ~petroleum ether (b. p. 40-65C) J, EXAMPLES 6 to 11 r By operating according to ~amples 1 to 5, but by varying the reagents, the products shown in Table I
hereinbelow are obtained.

For each of the products (I), the code number, the nature of the substitu ents, the method of preparation used and finally the melting point a~d crystallisation solvent, are indicated, T A B L E
~ . , , - m,P.oc (crys-' 50Ndoe R . R2 n _~3 ~, R4 ¦ solvent) 7 640 ~ 1 3 --C~ CH ~ c~3 B loq-107 (pet-¦ 40017, H I-CH3 1 2,Ni3 , A2 1 124-125(ethY
, l j! acetate) 40002 '. ~ -CH3, 2: . -C2H5 C2H5 j Al 1 88~89(isopro-' I pyl ether) ¦7921, H H 1 2 '-CH~CH3 , -CH~CH3 Al 68-69 (hexane) i I ! . isolated in . I i I the form of 40020 H 2 5 ~ Al h~drochloride i I ' I thyle thy~Ceton ~7~Z~31 T A B L E I (cont, ) Code ¦ Rl R~ ¦ n j R3 ~ R4 ~ mp, C (crys-No. tall~sation sol . ~ .. . .. ~ .... ~__ ~ _ l-S O Iat ed ln th e l CH I ! fCH3 ~ I form of 40021 I C~l -CH~ 3 H ! 2 j ~ I~CH~C;~ C 184-18fi (Lso-propan~1 ) I H3C isolated in~e ! >~ I form of tosy-40105 H -CH3 2, !Ir; ) I Al ¦ late, 110-112 H3 1 ¦ (isopropanol) . l l I isolated in th~
~CH~ i form of fu-40169 H -CH3 ~ c~ I (ethanol) 40176 R ¦-CH3 j 2 1 -CH2CH2CH3 ¦ -C1~2CH2CH3¦ Al li8t0hlatfed in f ¦
¦ I hyaroçhloride . l 198-199 (Ls~-l CH3 CH3 l propa nol ) 40178 H 1 3 1CH-CH2C~13, -CH-CH2CH3 Al I isolated iA Ihe i . . ~ ra te, 147 -148 . (acetone) CH3 ~C 3 ~ 1 40201 H I -CH 3 -CH -CH I Al , 80-81 ClsoPro, 3, CH3 C~13 l ¦ pylic ether) ;

40261 H -CH3 1 2 ~ tane) The products of the invention have been studed in animal pharmacology and in particular with a view to demon- -strating their properties.
Arrhythmic properties Protocol _ _ _ _ _ _ _ The anti-arrythmic power of these molecules was ...

~79~;~4~

assessed on an animal model of ventricular arrythmia.

Mongrel dogs are anaesthesized then subjected to the positioning, by retrt~grade catheterism, o a metal spir~
in the coronary bed. At the same time, a micro-emitter

5 frequency modulator i9 fixed to the animalls back and connected to two precordial electrodes.

The animal returned to its box then shows a pro-gressive thrombosis of the anterior interventricular artery Thus a localised, transmural myocardial infarction is consti-10 tuted, generating an abnormal, but repetitive electrical activity:ventricular tachycardia.

In this state, the drugs are administered per os (P, O ) and the telemetered system enables the development of the arrythmia to be followed in real time.

The sinusal systolic complexes and pathologies are permanently counted by electronic processes.

Thus, the quality and duration of action of the pro-duct may be quantified.
Results The results concerning various products are shown in Table II hereinbelow.

The activity of the tested products on the ventricular tachycardia is expressed either by the re-establishment of the sinusal rhythm, or by a considerable improvement in the ratio:
number of abnormal complexes number of sinusal complexes 74;~

T A B L E II

Products Dose,mg/kg Number Effect on the ventricu CM No.P. O. of animals lar tachycardia CM 761150 3 Sinusal rhythm or improvement between 70-90% from 3 or 4 hours .
Sinusal rhythm or CM 775350 4 90% improvement rom 1 1/2 hrs to S
hours CM 76 0 1 Sinusal rhythm or 4 50 90% improvement for 90 minutes 15 Activity as blood platelet anti-a Experimental protocol _ _ _ _ _ _ _ _ In vitro and ex vivo studies of the anti-aggregant activity were made according to Born's turbidiuretic technique.

The in vitro studies were made on platelet-rich 20 plasma (PRP) prepared from human venous blood.

The t~arious solutionq of the products to be tested were prepared extemporaneously. The CM 7753, 7611, 7640, 7921, 7954, 40018, 40020 were dissolved ac a concentration of Z x 10 2 M in acetone.

2 x 10 3 M aqueous solutions were prepared for the CM 40169, 40178, 2 ~Cll of the acetone solutions of the products or 40 ~1l1 of the aqueous solutions are incubated for 10 minutes at 37C with, respectively, 388 and 350~1 of PRP. ~fter this period of incubation, 10~(11 of the solution of collagen at 40~g/ml are added. For controls, Z~ll of acetone or 40 ~1 of distilled water are used.

~L~7~
-19~

The ex vivo studies in the baboon were made solely on the anti-aggregant activity of the CM 7753. In this case, the CM 7753 is administered orally at a rate of 50 mg/~cg/day for a period of g days.

Blood samples for analysing the platelet aggregation were made before the product was administered, 2 hours after administration of 50 mg/kg on day 1 and 2 hours after the last administration of day 5.

Platelet aggregation was quantified by the graphic determination of the n~aximum amplitude of aggregation (MA).

The results are expressed in % of inhibition of this parameter calculated with respect to the control (100% aggre-gation) .
Results ~
From the products studied, two proved particularly active with respect to the platelet aggregation induced by the collagen These are CM 7640 and GM 7611 (IC50 approxirnately situated at 30/~M).

The products CM 7753 and 7954 inhiblt at 50~ the platelet aggregation at a concentration close to 100 ~M. Other products, CM 40018, 40020, 40169, 40178 and 7921 inhibit the phenomenon of aggrega.tion less strongly (20 to 30% inhibition at a concentration of 100~l~,M).
EK vivo study Studied under ex vivo conditions, the CM 77S3 particularly inhibits the platelet aggregation induced by the collagen In four baboons used in the study, 100~ of inhibition was obtained after 5 days of treatment at the dose of 50 mg/kg/

~L7~;~41~

day, An anti-aggr~gant activity of lesser importance is also observed with respect to ADP.

These results show that the products according to the invention are endowed with a strong activity on experi-mental arr~lythmia and present a considerable blood platelet anti-aggregant activity. Consequently, the: products (I~ may be used in human therapeutics as protectors of the myocardium for correcting disorders in the ventricular rhythm of ischaemic origin as well as disorders in platelet aggregation.

The products may be presented in galenic forms of adrninistration to be taken orally (tablets, capsules, ~c . ) and parenterally (injectable ampoules).

The dose necessary for a platelet anti-aggregant activity or for restoring the sinusal rhythm in human beings is between about S0 and 150 mg by the I. V. route andabout 400 and 800 mg by t~ o~al route, per day.

By way of example, the following galenic pre-paration is indicated:
T blets CM 7753 0.200 g Microcrystalline celluk>se 0.140 g Lacto s e 0. 140 g Magnesium stearate 0. 020 g

Claims (2)

The embodiments of the invention in which an exclusive property of privilege is claimed, are defined as follows:

1. A process for the preparation of derivatives of pyrrole of formula (I) in which:
-R1 represents an atom of hydrogen, a lower alkyl group, a phenyl radical or a pyridyl-2 radical, -R2 represents an atom of hydrogen or a lower alkyl radical, -R3 and R4, which are identical or different, each represent a lower alkyl or cycloalkyl radical, or the group designates a cyclic amine radical comprising 1 or 2 cycles and being able to possess a second heteroatom and comprise substituents, and -n is equal to 2 or 3, as well as the salts of these derivatives with the mineral or organic acids, the process comprising saponifying in an alkaline medium a compound of formula heating the saponified compound in an acid medium to form the substituted butyric acid esterifying the substituted butyric and, converting the resultant ester into an amide by the action of ammonia, and heating the amide with ?-diketone of formula or dimethoxy-2,5 tetrahydrofuran, to produce the pyrrole derivative of formula (I).

2. A pyrrole derivative of formula (I) as defined in claim 1 when produced by the process of claim 1 or any obvious chemical equivalent thereof.