Compound of formula (I): ##STR1## wherein R, R.sub.1, R.sub.2, R', X and n are as defined in the description, and NEP and ACE inhibitory medicaments containing the same.

The present invention relates to new mercaptoalkanoyldipeptide compounds, 
mixed inhibitors of neutral endopeptidase (NEP) and angiotensin conversion 
enzyme (ACE), a process for their preparation and pharmaceutical 
compositions containing them. 
The new dipeptides according to the invention have the remarkable property 
of inhibiting both neutral endopeptidase (E.C. 3.4-24.11), which causes 
the inactivation of the auricular natriuretic peptide, and 
peptidyldipeptidase A (E.C. 3.4-15.1), which generates angiotensin II. 
They thus behave as mixed inhibitors of neutral endopeptidase (NEP) and 
peptidyldipeptidase A (ACE), capable of potentiating the natriuretic, 
diuretic and vasodilatory effects of the auricular natriuretic peptide and 
of blocking the hypertensive effects caused by angiotensin II. 
Numerous products possessing one or the other of those activities are 
known. 
BACKGROUND OF THE INVENTION 
The patent specification EP-B-38758 describes products that are inhibitors 
of the neutral endopeptidase called "encephalinase", since the enzyme 
degrades encephalins, which are endogenous ligands of morphine receptors. 
Those inhibitors are consequently useful as analgesics. 
Thus, in Nature, 228, (1980), 286-288, B. P. Roques et al. demonstrated 
that (R,S)-(2- mercaptomethyl-3-phenylpropionyl)glycine (thiorphan) 
exhibits an inhibitory property at a nanomolar concentration and acts like 
an analgesic by potentiating the action of encephalins, endogenous opiate 
peptides. 
Other encephalinase inhibitors having analgesic properties form the 
subject, for example, of the patent specifications FR-B-2 556 721 and 
EP-B-136 883. 
Patent specifications U.S. Pat. No. 4,053,651 and U.S. Pat. No. 4,684,660 
describe peptidyldipeptidase A inhibitors, which are useful as 
anti-hypertensives. 
Koehn et al., (J. Bio. Chem., 262, (1987), 11623-11627) and S. L. 
Stephenson and A. J. Kenny, (Biochem. J., 243, (1987), 183-187) reported 
that the auricular natriuretic peptide which is released by the heart, 
especially in the case of cardiac insufficiency, and which increases 
natriuresis and diuresis and thus exhibits a vasodilatory effect, is 
inactivated by the peripheral enzyme E.C. 24.11. Thus, the neutral 
endopeptidase inhibitor, thiorphan, and some of its derivatives are 
capable of increasing the half-life of the circulating auricular 
natriuretic peptide and of reducing blood pressure in the rat (G. Olins et 
al., Mol. Cell. Endocrinol., 61, (1989), 201-208; A. A. Seymour et al., 
Hypertension, 14, (1989), 87-97). However, none of those known neutral 
endopeptidase inhibitors has an intrinsic antihypertensive activity and a 
neutral endopeptidase inhibitor such as thiorphan, in clinical trials, 
causes natriuresis and diuresis without any significant hypotensive effect 
and without decreasing cardiac overload. 
In the patent specification U.S. Pat. No. 4,879,309, however, compounds of 
formula: 
##STR2## 
are described, which are useful in increasing natriuresis and diuresis and 
in reducing blood pressure. 
Mixed NEP and ACE inhibitors are described in the patent specifications 
FR-B-2 682 952 and FR-A-2 679 564. The described compounds have the 
following formulae: 
patent specification FR-B-2 682 952: 
##STR3## 
patent specification FR-A-2 679 564: 
##STR4## 
THE PRESENT INVENTION 
The present invention relates to new dipeptides that inhibit both neutral 
endopeptidase and peptidyldipeptidase A at very low concentrations. The 
compounds according to the invention differ from the compounds of the 
prior art, especially the patent specifications U.S. Pat. No. 4,879,309 
and FR-A-2 679 564, by the fact that all of the compounds of the present 
invention have in the C-terminal moiety an amino acid having 5 or 6 chain 
members that is substituted in the 5 or 6 position, respectively, by a 
phenyl or substituted phenyl radical. Furthermore, that very bulky amino 
acid imposes the Gly-imino acid chain formation so that an excellent 
inhibitory activity is obtained on the two enzymes. That type of chain 
formation results in compounds that exhibit a very powerful inhibitory 
activity on the two enzymes (K.sub.I of the order of 10.sup.-9 M), very 
long durations of activity and bioavailabilities suitable for blocking 
both the conversion enzyme to be found for the most part in the vessels, 
and neutral endopeptidase which degrades the natriuretic peptide, mainly 
in the proximal renal tubule. 
The new compounds according to the invention have the dual property of 
inhibiting both neutral endopeptidase and peptidyldipeptidase A. As a 
result, the hypotensive effect obtained with those mixed inhibitors is 
greater than that obtained with neutral endopeptidase inhibitors and 
peptidyldipeptidase A inhibitors used on their own or in admixture. In 
addition, the compounds of the invention exhibit a balanced inhibition of 
neutral endopeptidase and peptidyldipeptidase A. Indeed the IC.sub.50 
values obtained for a given compound are roughly identical for neutral 
endopeptidase and peptidyldipeptidase A. This demonstrates the superiority 
of the compounds of the invention to those of the prior art described in 
the patent specifications U.S. Pat. No. 4,879,309 and FR-A-2 679 564. 
Thus, the compounds of the present invention are very effective in the 
treatment of congestive cardiac deficiencies and various types of 
hypertension, and in the treatment of atherosclerosis, cardiac ischaemia, 
chronic renal deficiencies, and cardiac accidents associated with a 
pulmonary disorder. They are also effective in reducing side-effects 
caused by treatment with cyclosporin. 
The invention relates more especially to compounds of the general formula 
(I): 
##STR5## 
wherein: 
--R is selected from hydrogen, an acyl radical containing from 1 to 6 
carbon atoms in straight or branched chain, the radicals benzoyl, 
naphthoyl and adamantoyl and the radical 
##STR6## 
wherein R.sub.1, R.sub.2, R', X and n are as defined below, 
R.sub.1 and R.sub.2, which are identical or different, are each selected, 
independently of the other, from hydrogen, a hydroxy radical, an alkyl 
radical containing from 1 to 6 carbon atoms in straight or branched chain, 
an alkoxy radical containing from 1 to 6 carbon atoms in straight or 
branched chain, a halogen atom selected from fluorine, chlorine, bromine 
and iodine, a nitro group, an amino group, a carboxy radical, an 
alkoxycarbonyl radical containing from 1 to 6 carbon atoms in straight or 
branched chain, a benzyloxycarbonyloxy radical, a phosphonate radical, a 
sulphonate radical, the radical SO.sub.2 --NH.sub.2 and the radical 
SO.sub.2 --NH-alkyl wherein the term alkyl denotes a saturated hydrocarbon 
group containing from 1 to 6 carbon atoms in straight or branched chain, 
R' is selected from hydrogen, an alkyl radical containing from 1 to 20 
carbon atoms in straight or branched chain, an aralkyl radical and a 
cycloalkylalkyl radical, 
X is selected from oxygen, sulphur, the group CH.sub.2 and the group NH, 
n is selected from the integers 1 and 2, 
it being understood that: 
"aralkyl radical" denotes a radical formed by an aryl group selected from 
phenyl and naphthyl that is bonded to an alkyl radical containing from 1 
to 6 carbon atoms in straight or branched chain, 
"cycloalkylalkyl radical" denotes a radical formed by a cycloalkyl group 
containing from 3 to 8 carbon atoms that is bonded to an alkyl radical 
containing from 1 to 6 carbon atoms in straight or branched chain, 
and also to their stereoisomeric forms in pure form or in a mixture, and to 
their possible pharmaceutically acceptable addition salts. 
The present invention relates also to a process for the preparation of 
compounds of formula (I) which is characterised in that the dipeptide of 
formula (II): 
##STR7## 
wherein R.sub.2, R', X and n are as defined for the compound of formula 
(I), is subjected to acylation with an acid of formula (III): 
##STR8## 
wherein R and R.sub.1 are as defined for the compound of formula (I), 
under the conditions customarily used in peptide synthesis and described, 
for example, by Bodansky et al. ("Peptide Synthesis", J. Wiley and Sons 
Edit). 
The dipeptides of formula (II) are obtained by condensation of the 
Z-glycine acyl chloride of formula (IV): 
##STR9## 
with an ester of formula (V): 
##STR10## 
wherein R.sub.2, R', X and n are as defined hereinbefore, followed by 
catalytic hydrogenation. 
The compound of formula (II) can be prepared from the corresponding 
.alpha.-amino acid by halogenating deamination according to Fisher et al. 
(Ann., 357, (1907), 1-24), followed by nucleophilic substitution of the 
halogen atom. 
The compounds of formula (I) can also be obtained by condensation, for 
example with the aid of Castro's reagent, of compounds of formula (V) with 
the pseudodipeptides of formula (VI): 
##STR11## 
wherein R and R.sub.1 are as defined hereinbefore. 
The pseudodipeptides of formula (VI) are obtained by the coupling of acids 
of formula (III) with glycine tert-butyl ester in accordance with 
conventional methods used in peptide synthesis, followed by deprotection 
of the acid function with trifluoroacetic acid. 
The compounds of formula (V) are obtained according to methods described, 
for example, by J. N. Barton et al. (J. Med. Chem., 30, (1990), 
1606-1615). 
The compounds of formula (I) wherein R' represents hydrogen can form 
pharmaceutically acceptable salts with mineral or organic bases. Among the 
mineral or organic bases used to form those salts there may be mentioned 
more especially, and in a non-limiting manner, ammonium, sodium and 
calcium hydroxides, N-methyl-D-glucamine, lysine, arginine and 
dicyclohexylamine. 
The compounds of the present invention may, where appropriate, exist in the 
form of pure stereoisomers or in the form of mixtures of stereoisomers. 
The pure stereoisomers are easily accessible by the one skilled in the art 
from the mixtures of stereoisomers using classic separation techniques, or 
asymetric syntheses of the starting materials. 
The carbon atoms makred with an asterisk (*) in formula (I) are centres of 
asymmetry. The present compounds of the present invention are those in 
which: 
the carbon atom carrying the radical 
##STR12## 
has the S configuration, and 
the carbon atom carrying the radical 
##STR13## 
has the S configuration, and 
the radicals 
##STR14## 
on the one side and 
##STR15## 
on the other side are located in the cis configuration in relation to the 
mean plane of the ring. 
The Applicant has discovered that the compounds of the invention have very 
valuable pharmacological properties. 
The compounds of the present invention, when administered to mammals, are 
useful in the treatment and prevention of congestive cardiac deficiencies, 
essential hypertension, hypertension associated with an increase in blood 
volume, cardiac and/or renal insufficiency and pulmonary angina, and have 
a protective effect against thickening of the vascular wall. That results 
from their dual inhibitory action on neutral endopeptidase and 
peptidyldipeptidase 
A. As a result of their pharmacological properties, the compounds of the 
present invention are also useful in the treatment and prevention of 
atherosclerosis and cardiac ischaemia. They are also useful in the 
prevention of hypertrophy, and of fibrosis of the left ventricle and of 
the pulmonary heart. Patients who have undergone cardiac and/or renal 
transplants are often treated in the long term with cyclosporin, which has 
as side-effects an increase in blood pressure and salt retention. The 
compounds of the invention have properties that oppose those effects and 
are thus useful in reducing the side-effects caused by cyclosporin. 
Peptidyldipeptidase A inhibitors are products known for the treatment of 
certain hypertensions: they are capable of blocking the increase in blood 
pressure caused by an increase in vascular resistance and in blood volume 
resulting from the formation of angiotensin II from angiotensin I. 
Another important peptide implicated in the regulation of arterial pressure 
is the auricular natriuretic peptide released by the heart, which has a 
vasodilatory property and which is capable of controlling diuresis and 
natriuresis. The auricular natriuretic peptide is degraded by neutral 
endopeptidase in peripheral tissues. Neutral endopeptidase inhibitors, 
such as thiorphan, induce significant diuresis and natriuresis in man 
without causing an increase in the levels of renin and aldosterone usually 
observed with the diuretics generally employed in association with ACE 
inhibitors. The effects of neutral endopeptidase inhibitors on blood 
pressure when used alone, however, are weak. 
The mixed inhibitors of neutral endopeptidase and peptidyldipeptidase A can 
alleviate human hypertension of various origins and may be used without 
the coadministration of diuretics and without supplying potassium. 
The new products of the present invention are very effective, 
preventatively and curatively, in the treatment of congestive cardiac 
deficiencies and various types of hypertension, especially hypertension 
associated with an increase in blood volume, essential hypertension, 
atherosclerosis, cardiac ischaemia, cardiac and/or renal insufficiency, 
cor pulmonale, and pulmonary angina, and have a protective effect against 
thickening of the vascular wall while protecting bradykinin and the 
auricular natriuretic peptide from inactivation. They are also effective 
in reducing side-effects caused by treatment with cyclosporin. 
As a result of the dual property of the compounds of the invention of 
inhibiting both neutral endopeptidase and peptidyldipeptidas A, the 
hypotensive effect obtained with those mixed inhibitors is greater than 
that obtained with neutral endopeptidase inhibitors and 
peptidyldipeptidase A inhibitors used alone or in admixture. 
The present invention relates also to pharmaceutical compositions 
comprising compounds of formula (I), or their stereoisomers in pure form 
or in the form of a mixture, in the form of the base or pharmaceutically 
acceptable addition salts, in combination with one or more inert, 
non-toxic excipients or carriers. 
Among the pharmaceutical compositions according to the invention there may 
be mentioned more especially those which are suitable for oral, 
parenteral, nasal, rectal, perlingual, ocular or respiratory 
administration, and especially tablets or dragees, sublingual tablets, 
sachets, paquets, gelatin capsules, glossettes, lozenges, suppositories, 
creams, ointments, dermal gels, injectable or drinkable preparations, 
aerosols, and eye or nose drops. 
The choice of the carrier and the levels of active substance in the carrier 
are generally determined as a function of the solubility and chemical 
properties of the product, the particular mode of administration and 
pharmaceutical practice arrangements. For example, excipients such as 
lactose, sodium citrate, calcium carbonate, dicalcium phosphate and 
disintegrators such as starch, alginic acids and certain complex silicates 
associated with lubricants such as magnesium stearate, sodium 
laurylsulphate and talc, may be used for the preparation of tablets. To 
prepare a capsule, it is advantageous to use lactose and 
high-molecular-weight polyethylene glycols. When aqueous suspensions are 
used, they may contain emulsifiers or agents facilitating suspension. 
Diluents such as ethanol, propylene glycol, glycerol and chloroform or 
mixtures thereof may also be used. 
There are used for parenteral administration, suspensions or solutions of 
the products according to the invention in sesame oil, peanut oil or olive 
oil, or aqueous solutions of propylene glycol as well as sterile aqueous 
solutions of pharmaceutically acceptable salts. Solutions of salts of the 
products according to the invention are especially useful for 
administration by intramuscular or subcutaneous injection. Aqueous 
solutions, including also solutions of salts in pure distilled water, can 
be used for intravenous administration provided that their pH is suitably 
adjusted, that they are judiciously buffered and rendered isotonic with an 
adequate amount of glucose or sodium chloride, and that they are 
sterilised by heating or micro-filtration. 
The doses used in the methods according to the invention are those which 
result in a maximum therapeutic effect until an improvement is obtained. 
Generally, the doses used are those which are therapeutically effective in 
lowering blood pressure when treating hypertension. In general, the doses 
administered by the oral route are from 0.1 to 100 mg/kg, preferably from 
1 to 10 mg/kg, and those administered by the intravenous route are from 
0.01 to 10 mg/kg, preferably from 0.1 to 5 mg/kg, it being understood that 
in each particular case the doses will be determined as a function of 
factors peculiar to the patient to be treated, such as age, weight, 
general state of health and other characteristics that may influence the 
efficacy of the medicament. 
The compounds according to the invention may be administered as frequently 
as is necessary to obtain the desired therapeutic effect. Some patients 
may respond rapidly to a more or less strong dose and may be satisfied 
with much weaker maintenance doses. For other patients, it may be 
necessary to have treatments spread out at a rate of from 1 to 4 doses per 
day as a function of the physiological needs of each particular patient. 
Generally, the active ingredient may be administered orally from 1 to 4 
times per day. For other patients it will be necessary to prescribe no 
more than one or two doses per day. 
The compounds of the invention may be used in injectable form in urgent 
cases of acute hypertension Such a treatment may be followed by an 
intravenous perfusion of the active ingredient in order to obtain and 
maintain the desired therapeutic effect. 
In the present application, the abbreviations used correspond to the 
following products: 
PyBrOP: bromoxy-tripyrrolidinophosphonium hexafluorophosphate 
Cbz: carbobenzoxy (benzyloxycarbonyl) 
Z: benzyloxycarbonyl 
BOP: benzotriazol-1-yloxy-tris(dimethylamino)phosphonium 
hexafluorophosphate 
DCC: dicyclohexylcarbodiimide

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The following Example illustrate the invention without, however, limiting 
it in any way. The starting materials are known or are prepared by known 
methods of operation. 
PREATION A: N-(2-Acetylthio-3-phenylpropanoyl)glycine tert-butyl ester 
A solution of 3.7 g of glycine tert-butyl ester hydrochloride and 3.8 ml of 
triethylamine in 40 ml of chloroform, a solution of 3 g of 
1-hydroxybenzotriazole in 30 ml of tetrahydrofuran and a solution of 6.9 g 
of DCC in trichloromethane are added in succession to 5 g of 
2-acetylthio-3-phenylpropanoic acid dissolved in 40 ml of tetrahydrofuran. 
After stirring at room temperature for one night, the reaction mixture is 
filtered and evaporated to dryness. The residue is taken up in ethyl 
acetate and washed in succession with a 10% citric acid solution, water, 
10% sodium hydrogen carbonate solution, water, and a saturated sodium 
chloride solution, and is then dried over sodium sulphate. After 
filtration and evaporation to dryness, 7.5 g, of an oil are obtained. 
Yield: 98% 
R.sub.f : 0.65 (n-hexane/ethyl acetate 2:1) 
PREATION B: N-(2-Acetylthio-3-phenylpropanoyl)glycine 
7.5 g of the compound obtained in Preparation A are dissolved in 10 ml of 
dichloromethane. 17 ml of trifluoroacetic acid are added at 0.degree. C. 
After 30 minutes at 0.degree. C., the mixture is stirred for 3 hours at 
room temperature, then evaporated to dryness. The residue is taken up 
three times in a 50:50 mixture of diethyl ether/n-hexane to yield 6.2 g of 
an oil corresponding to the expected product. 
Yield: 97% 
R.sub.f : 0.53 (dichloromethane/methanol, 9:1) 
PREATION C: 2-Acetylthio-3-(para-benzyloxycarbonyioxyphenyl)propanoic 
acid 
A solution of potassium thioacetate (prepared from 2.5 ml of thioacetic 
acid and 2 g of potassium carbonate in water) is added to 10 g of 
2-bromo-3-(para-benzyloxycarbonyloxyphcnyl)propanoic acid (prepared in 
accordance with K. Koga et al. Chem. Pharm. Bull., 26, 178 (1978)) 
dissolved in 1M sodium hydroxide. The mixture is stirred for 2 days at 
room temperature. After acidification with 1N hydrochloric acid, the 
aqueous phase is extracted three times with ethyl acetate, washed with a 
saturated sodium chloride solution and dried over sodium sulphate. After 
filtration and evaporation to dryness a yellow oil is obtained which is 
purified by chromatography on silica gel (eluant: n-hexane/ethyl 
acetate/acetic acid 8:2:0.5). 6.4 g of an oily product are obtained. 
Yield :65% 
R.sub.f : 0.49 (n-hexane/ethyl acetate/acetic acid, 6:4:0.5). 
PREATION D: 
N-2-Acetylthio-3-(para-benzyloxcarbonyioxyphenyl)propanoyl!-glycine 
tert-butyl ester 
1.6 g of the compound obtained in Preparation C are condensed under the 
conditions of Preparation A with 0.72 g of glycine tert-butyl ester. 2 g 
of a pale yellow oil are obtained. 
Yield: 96% 
R.sub.f : 0.57 (hexane/ethyl acetate, 1:1) 
PREATION E: 
N-2-Acetylthio-3-(para-benzyloxycarbonyloxyphenyl)propanoylglycine 
2 g of the compound obtained in Preparation D are treated under the 
conditions of Preparation B. After chromatography on silica gel in a 
hexane/ethyl acetate/acetic acid mixture, 4:6:0.5, 1.35 g of an oil is 
obtained which slowly crystallises. 
Yield: 76% 
R.sub.f : 0.25 (hexane/ethyl acetate/acetic acid, 4:6:0.5). 
PREATION F: 2-Acetylthio-3-(para-nitrophenyl)propanoic acid 
2.7 g of 2-bromo-3-(para-nitrophenyl)propanoic acid (prepared from 
(para-nitrophenyl)alanine) are added at 0.degree. C., under nitrogen, to a 
solution of sodium thioacetate (prepared from 0.73 g of sodium hydride and 
1.05 ml of thioacetic acid) in dimethylformamide. After stirring for 48 
hours at room temperature, then evaporating to dryness and taking up the 
residue in water, the mixture is treated as described in Preparation C. 
2.3 g of a pale yellow oil are obtained. 
Yield:88% 
R.sub.f : 0.63 (dichloromethane/methanol/acetic acid, 9:1:0.2) 
PREATION G: N-Glycyl-5-(meta-hydroxyphenyl)proline methyl ester 
Step a: N-(N-Cbz)-glycyl!-5-(meta-hydroxyphenyl)proline methyl ester 
0.6 g of Z-glycine dissolved in dichloromethane is coupled with 0.83 g of 
5-(meta-hydroxyphenyl)proline methyl ester in the presence of 2.06 g of 
PyBrOP and 2.6 ml of diisopropylethylamine. After stirring for 4 hours at 
room temperature, the organic phase is washed (sodium hydrogen carbonate, 
water, citric acid, water), dried over sodium sulphate, filtered and 
evaporated to dryness. The oily residue is chromatographed on silica gel 
(n-hexane/ethyl acetate. 4:6). A white solid corresponding to the expected 
product is obtained. 
Yield :33% 
Melting point: 173.degree. C. 
R.sub.f : 0.17 (n-hexane/ethyl acetate, 4:6) 
Step b: N-Glycyl-5-(meta-hydroxyphenyl)proline methyl ester 
0.39 g of the compound obtained in Step a is hydrogenated at room 
temperature and normal pressure in the presence of 10% palladium-on-carbon 
and 1 equivalent of 1N hydrochloric acid dissolved in methanol. After 
stirring for 3 hours at room temperature, the catalyst is filtered off and 
the solvent is evaporated to dryness. 
Yield: 100% 
PREATION H: N-(N-Cbz)-glycyl!-5-(para-methylphenyl)proline methyl ester 
1 equivalent of Z-glycine dissolved in acetone is treated with cyanuric 
chloride in the presence of triethylamine. After stirring for 3 hours at 
room temperature, the mixture is evaporated to dryness. The residue is 
taken up in carbon tetrachloride and 1 equivalent of 
5-(para-methylphenyl)proline methyl ester is added in solution in 
dichloromethane and in the presence of triethylamine. After stirring for 3 
hours at room temperature, the reaction mixture is evaporated to dryness, 
taken up in ethyl acetate, washed, dried, and evaporated to dryness again. 
The oily residue so obtained is chromatographed in an n-hexane/ethyl 
acetate mixture, 1:1, to yield a white solid. 
Yield: 41% 
R.sub.f : 0.18 (n-hexane/ethyl acetate, 1:1) 
PREATION I: N-(N-Cbz)-glycyl!-5-(ortho-methylphenyl)proline methyl 
ester 
This compound is obtained from Z-glycine and 5-(ortho-methylphenyl)proline 
methyl ester in accordance with the process described in Preparation H. 
The oily product so obtained is purified by chromatography in an 
n-hexane/ethyl acetate mixture, 55:45, to yield a colourless oil. 
Yield :42% 
R.sub.f : 0.21 (n-hexane/ethyl acetate, 1:1) 
EXAMPLE 1: N-N-(2-Acetylthio-3-phenylpropanoyl) glycyl!-5-phenylproline 
tert-butyl ester 
A solution of 5.4 g of 5-phenylproline tert-butyl ester and 3.35 ml of 
triethylamine in 40 ml of trichloromethane, a solution of 2.96 g of 
1-hydroxybenzotriazole in 30 ml of tetrahydrofuran and a solution of 6.76 
g of DCC in 30 ml of trichloromethane are added in succession at 0.degree. 
C. to 6.1 g of the compound obtained in Preparation B dissolved in 40 ml 
of tetrahydrofuran. The reaction mixture is treated as described in 
Preparation A. The crude product is purified by chromatography on silica 
gel with a hexane/ethyl acetate mixture, 2:1, as eluant. 6.47 g of an oily 
compound are obtained. 
Yield: 60% 
R.sub.f : 0.49 (ethyl acetate/hexane, 1:1) 
EXAMPLE 2: N-N-(2-Acetylthio-3-phenylpropanoyl)-glycyl!-5-phenylproline 
5 ml of trifluoroacetic acid are added at 0.degree. C. to a solution of 3.2 
g of the compound obtained in Example 1 in 10 ml of dichloromethane. The 
mixture is stirred for 30 minutes at 0.degree. C., then for 2 hours 30 
minutes at room temperature. After evaporation to dryness, the oily 
residue precipitates in an ether/hexane mixture, 1:1.1.66 g of a white 
solid are obtained. 
Yield: 58.5% 
R.sub.f : 0.57 (dichloromethane/methanol, 9:1) 
EXAMPLE 3: N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-5-phenylproline 
0.700 g of the compound obtained in Example 2 is dissolved in 10 ml of 
degassed methanol. 5 ml of a degassed 1M sodium hydroxide solution are 
added at 0.degree. C. and the mixture is stirred for 1 hour at 0.degree. 
C. and then for 3 hours at room temperature. The mixture is acidified with 
1M hydrochloric acid until a pH of 1 is reached and is concentrated in 
vacuo. The residue is taken up in water and the aqueous phase is extracted 
with ethyl acetate. The organic phase is washed with water, with a 
saturated sodium chloride solution, then dried over sodium sulphate. After 
filtration and evaporation to dryness, 610 mg of a pale yellow oil are 
obtained which slowly crystallises. 
Yield :96% 
Melting Point: 75.degree. C. 
R.sub.f : 0.24 (dichloromethane/methanol, 95:5) 
EXAMPLE 4: 
N-N-(2-Acetylthio-3-phenylpropanoyl)glycyl!-5-(ortho-hydroxyphenyl)-proli 
ne methyl ester 
0.500 g of the compound obtained in Preparation B and 0.400 g of 
5-(ortho-hydroxyphenyl)-proline methyl ester are condensed under the 
conditions of Example 1. After chromatography on silica gel with a 
hexane/ethyl acetate mixture, 6:4, 0.32 of the expected product is 
obtained in the form of an oil. 
Yield: 50% 
R.sub.f : 0.2 (cyclohexane/ethyl acetate, 1:1) 
EXAMPLE 5: 
N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-5-(ortho-hydroxyphenyl)-proline 
0.300 g, of the compound obtained in Example 4 is treated as described in 
Example 3. 0.200 g of the expected compound is obtained. 
Yield: 88% 
R.sub.f : 0.69 (dichloromethane/methanol/acetic acid, 9: 1:0.5) 
EXAMPLE 6: 
N-N-2-Acetylthio-3-(para-benzyloxycarbonyloxyphenyl)propanoylglycyl-5-(o 
rtho-hydroxyphenyl)proline methyl ester 
0.65 of 5-(ortho-hydroxyphenyl)proline methyl ester, 0.7 ml of 
diisopropylethylamine and 1.27 g of BOP are added at 0.degree. C. to a 
solution of 0.500 g of the compound obtained in Preparation E in 
dichloromethane. Stirring is maintained at room temperature for 48 hours. 
After treatment in accordance with conventional conditions, the oil 
obtained is purified by chromatography in a hexane/ethyl acetate mixture, 
4:6. 0.35 g of an oily product is obtained. 
Yield: 47% 
R.sub.f : 0.53 (cyclohexane/ethyl acetate/acetic acid, 3:7:0.2) 
EXAMPLE 7 : 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(ortho-hydroxyp 
henyl)proline 
2 ml of degasses 1M sodium hydroxide are added at 0.degree. C. to 0.200 g 
of the compound obtained in Example 6 in 1 ml of degasses methanol. After 
stirring for 1 hour at 0.degree. C. then for 2 hours at room temperature, 
the reaction mixture is treated as described in Example 3. 0.125 g of a 
white solid is obtained. 
Yield: 89% 
R.sub.f : 0.34 (dichloromethane/methanol/acetic acid, 9:1:0.2) 
EXAMPLE 8: 
N-N-2-Acetylthio-3-(para-benzyloxycarbonyloxyphenyl)propanoyl!-glycyl!-5 
-phenylproline tert-butyl ester 
0.590 g of the compound obtained in Preparation C is condensed with 
Gly-(5-phenyl)-Pro dipeptide tert-butyl ester under the conditions of 
Preparation A. 1 g of the expected compound is obtained. 
Yield: 98% 
R.sub.f : 0.46 (hexane/ethyl acetate, 1:2) 
EXAMPLE 9: 
N-N-2-Acetylthio-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-phenylproline 
1 g of the compound obtained in Example 8 is dissolved in a mixture of 
boron tris(trifluoroacetate) and trifluoroacetic acid under nitrogen at 
0.degree. C. The mixture is stirred at the same temperature for 20 
minutes. After evaporation to dryness, the residue is taken up 3 times in 
methanol and evaporated to dryness again. The oily residue then 
precipitates in diethyl ether thus yielding 710 g of a pale yellow powder. 
Yield: 75% 
R.sub.f : 0.71 (dichloromethane/methanol/acetic acid, 9:1:0.5) 
EXAMPLE 10: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-phenylproline 
450 mg of the compound obtained in Example 9 are dissolved in 5 ml of 
degassed methanol. 2 ml of 1M sodium hydroxide are added at 0.degree. C., 
and the reaction is continued as described in Example 3. 400 mg of the 
expected compound are obtained in the form of a white solid. 
Yield :97% 
R.sub.f : 0.83 (trichloromethane/methanol/acetic acid, 7:3:0.5) 
EXAMPLE 11: 
N-N-2-Acetylthio-3-(para-nitrophenyl)propanoyl!glycyl!-5-phenyl-proline 
tert-butyl ester 
By reacting 1 g of the compound obtained in Preparation F and 1.15 g of 
N-glycyl-5phenylproline tert-butyl ester under the conditions described in 
Example 1, an oily compound is obtained which is purified by 
chromatography on silica gel in a cyclohexane/ethyl acetate mixture, 1:1 
1.09 g of a pale yellow oil are obtained. 
Yield : 53% 
EXAMPLE 12: 
N-N-2-Acetylthio-3-(para-nitrophenyl)propanoyl!glycyl!-5-phenylproline 
2 ml of trifluoroacetic acid are added at 0.degree. C. to 0.72 g, of the 
compound obtained in Example 11 dissolved in 2 ml of dichloromethane. 
After treatment under the conditions described in Example 2, 0.58 g of a 
white solid is obtained. 
Yield: 90% 
R.sub.f : 0.39 (dichloromethane/methanol, 9:1) 
EXAMPLE 13: 
N-N-2-Acetylthio-3-(para-aminophenyl)propanoyl!glycyl!-5-phenylproline 
300 mg of the compound obtained in Example 12 are dissolved in 15 ml of 
methanol and a few drops of acetic acid, then the mixture is hydrogenated 
under normal pressure in the presence of palladium-on-carbon. After 
filtration of the catalyst and evaporation of the solvent 0.280 g of a 
white solid is obtained. 
Yield: 100% 
R.sub.f : 0.31 (dichloromethane/methanol/acetic acid 9:1:0.25) 
EXAMPLE 14: 
N-N-2-Mercapto-3-(para-aminophenyl)propanoyl!glycyl!-5-phenylproline 
0.150 g of the compound obtained in Example 13 is treated under the 
conditions of Example 3. After customary treatment of the organic phase, 
0.103 g of a white solid is obtained. 
Yield: 89% 
R.sub.f : 0.36 (dichloromethane/methanol/acetic acid, 9: 1:0.3) 
EXAMPLE 15: 
N-N-2-Acetylthio-3-(para-benzyloxycarbonyioxyphenyl)propanoyl!glycyl!-5- 
(para-aminophenyl)proline methyl ester 
The compound of Preparation E is coupled with 5-(para-aminophenyl)proline 
methyl ester in accordance with the conditions described in Example 6. An 
oily product is obtained which is chromatographed in a 
dichloromethane/methanol/acetic acid mixture, 15:0.4:0.1. A white foamy 
product is obtained. 
Yield: 35% 
R.sub.f : 0.25 (dichloromethane/methanol/acetic acid, 9:1:0.25) 
EXAMPLE 16: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(para-aminophen 
yl)proline 
The compound obtained in Example 15 is treated in accordance with the 
conditions of Example 7. A white solid corresponding to the expected 
product is obtained. 
Yield: 60% 
R.sub.f : 0.37 (dichloromethane/methanol/acetic acid, 9: 1:0.5) 
EXAMPLE 17: 
N-N-2-Acetylthio-3-(para-benzyloxycarbonyloxyphenyl)propanoyl!glycyl!-5- 
(meta-hydroxyphenyl)proline methyl ester 
0.35 g of the compound obtained in Preparation C is coupled with 0.3 g of 
the compound obtained in Preparation G in accordance with the process 
described in Preparation A. An oily product is obtained which is 
chromatographed on silica gel in a hexane/ethyl acetate mixture, 4:6. 0.24 
g of the expected product is obtained. 
Yield : 40% 
R.sub.f : 0.37 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 18: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(metahydroxyphe 
nyl)proline 
0.24 g of the compound obtained in Example 17 is dissolved in degassed 
methanol, then treated with 4 equivalents of a degassed aqueous 1N sodium 
hydroxide solution. After stirring for 30 minutes at 0.degree. C. and for 
2 hours at room temperature, the reaction mixture is acidified and 
extracted with ethyl acetate. After evaporation to dryness, 0.12 g of a 
white solid is obtained. 
Yield: 71% 
R.sub.f : 0.34 (dichloromethane/methanol/acetic acid, 9:1:0.5) 
EXAMPLE 19: 
N-N-(2-Acetylthio-3-phenylpropanoyl)glycyl!-5-(meta-hydroxyphenyl)-prolin 
e methyl ester 
The compound obtained in Preparation G is coupled with 
2-acetylthio-3-phenylpropanoic acid in accordance with the process 
described in Preparation A. An oily product is obtained which is 
chromatographed in a mixture of n-hexane/ethyl acetate, 1:1. 
Yield: 50% 
R.sub.f : 0.28 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 20: 
N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-5-(meta-hydroxyphenyl)proline 
The compound obtained in Example 19 is treated in accordance with the 
process of Example 3. A pasty product corresponding to the expected 
compound is obtained. 
Yield: 85% 
R.sub.f : 0.29 (dichloromethane/methanol/acetic acid, 9:0.5:0.25) 
EXAMPLE 21: 
N-N-2-Acetylthio-3-(para-benzyloxycarbonyloxyphenyl)propanoyl!glycyl!-5- 
(para-hydroxyphenyl)proline methyl ester 
The compound obtained in Preparation C is coupled with 
N-glycyl-5-(para-hydroxyphenyl)proline methyl ester, prepared in 
accordance with the processes described in Steps a and b of Preparation G. 
An oily product corresponding to the expected compound is obtained. 
Yield : 50% 
R.sub.f : 0.26 (cyclohexane/ethyl acetate/acetic acid, 5.5:4.5:0.5) 
EXAMPLE 22: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5,(para-hydroxyph 
enyl)proline 
The compound of Example 21 is treated in accordance with the process 
described in Example 3. A pasty product is obtained. 
Yield: 77% 
R.sub.f : 0.24 (dichloromethane/methanol/acetic acid, 9:1:0.5) 
EXAMPLE 23: 
N-N-2-Acetylthio-3-(para-chlorophenyl)propanoyl!glycyl!-5-(ortho-hydroxy 
phenyl)proline methyl ester 
Condensation of 2-acetylthio-3-(para-chlorophenyl)propanoic acid with 
N-glycyl-5-(ortho-hydroxyphenyl)proline methyl ester, obtained in 
accordance with the same protocols as those described in Preparation G, 
yields the expected product in the form of an oil after chromatography in 
an n-hexane/ethyl acetate mixture, 1:1. 
Yield: 53% 
R.sub.f : 0.38 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 24: 
N-N-2-Mercapto-3-para-chlorophenyl)propanoyl!glycyl!-5-(ortho-hydroxyphe 
nyl)proline 
The compound obtained in Example 23 is treated in accordance with the 
process described in Example 3. A pasty white solid is obtained. 
Yield: 88% 
R.sub.f : 0.26 (dichloromethane/methanol/acetic acid, 9:0.5:0.25) 
EXAMPLE 25: 
N-N-2-Acetylthio-3-(para-methoxyphenyl)propanoyl!glycyl!-5(ortho-hydroxy 
phenyl)proline methyl ester 
Condensation of 2-acetylthio-3-(para-methoxyphenyl)propanoic acid with 
N-glycyl-5-(ortho-hydroxyphenyl)proline methyl ester, obtained in 
accordance with the same protocols as those described in Preparation G, 
yields the expected product in the form of an oil after chromatography in 
an n-hexane/ethyl acetate mixture, 4:6. 
Yield:50% 
R.sub.f : 0.28 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 26: 
N-N-2-Mercapto-3-(para-methoxyphenyl)propanoyl!glycyl!-5-(orthohydroxyph 
enyl)proline 
By treatment of the compound obtained in Example 25 in accordance with the 
conditions described in Example 3, a while solid is obtained. 
Yield: 88% 
R.sub.f : 0.42 (dichloromethane/methanol/acetic acid, 9:0.5:0.25) 
EXAMPLE 27: 
N-N-2-Acetylthio-3-(para-methoxyphenyl)propanoyl!glycyl!-5-(ortho-methox 
yphenyl)proline methyl ester 
Condensation of 2-acetylthio-3-(para-methoxyphenyl)propanoic acid with 
N-glycyl-5-(ortho-methoxyphenyl)proline methyl ester, obtained in 
accordance with the same protocols as those decribed in Preparation G, 
yields the expected product in the form of a white solid after 
chromatography in an n-hexane/ethyl acetate mixture, 1:1. 
Yield: 59% 
R.sub.f : 0.26 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 28 : 
N-N-2-Mercapto-3-(para-methoxyphenyl)propanoyl!glycyl!-5-(orthomethoxyph 
enyl)proline 
Treatment of the compound obtained in Example 27 in accordance with the 
conditions of Example 3 yields a white solid. 
Yield: 89% 
R.sub.f : 0.22 (cyclohexane/ethyl acetate/acetic acid, 5:5:0.5) 
EXAMPLE 29: 
N-N-(2-Acetylthio-3-phenylpropanoyl)glycyl!-5-(para-methylphenyl)proline 
methyl ester 
The compound obtained in Preparation H is deprotected in accordance with 
the process described in Step b of Preparation G; the dipeptide obtained 
is coupled with 2-acetylthio-3phenylpropanoic acid in accordance with the 
process described in Preparation A. The oily product so obtained is 
chromatographed in an n-hexane/ethyl acetate mixture, 5.5:4.5, to yield a 
white solid. 
Yield: 60% 
R.sub.f : 0.55 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 30: 
N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-5-(para-methylphenyl)proline 
The compound obtained in Example 29 is treated in accordance with the 
process described in Example 3. A white solid is obtained. 
Yield: 89% 
R.sub.f : 0.59 (dichloromethane/methanol/acetic acid, 9:0.5:0.5) 
EXAMPLE 31: 
N-N-2-Acetylthio-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(para-methylp 
henyl)proline methyl ester 
The compound obtained in Preparation H is deprotected in accordance with 
the process described in Step b of Preparation G; the dipeptide obtained 
is coupled with the compound obtained in Preparation C in accordance with 
the process described in Preparation A. The oily product so obtained is 
chromatographed in an n-hexane/ethyl acetate mixture, 1:1, to yield a 
white solid. 
Yield: 52% 
R.sub.f : 0.14 (n-hexane/ethyl acetate, 1:1) 
EXAMPLE 32: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(para-methylphe 
nyl)proline 
The compound obtained in Example 31 is treated in accordance with the 
process described in Example 3. A white solid is obtained. 
Yield: 92% 
R.sub.f : 0.60 (dichloromethane/methanol/acetic acid, 9:1:0.5) 
EXAMPLE 33: 
N-N-2-Acetylthio-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(ortho-methyl 
phenyl)proline methyl ester 
The compound obtained in Preparation I is deprotected in accordance with 
the process described in Step b of Preparation G and the dipeptide 
obtained is coupled with the compound obtained in Preparation C in 
accordance with the process described in Preparation A. The oily product 
so obtained is purified by chromatography in an n-hexane/ethyl acetate 
mixture, 1:1, to yield an oil. 
Yield: 56% 
R.sub.f : 0.28 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 34: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(ortho-methylph 
enyl)proline 
The compound obtained in Example 33 is treated in accordance with the 
process of Example 3. A white solid is obtained. 
Yield: 87% 
Melting point: 130.degree. C. (decomposition) 
R.sub.f : 0.24 (n-hexane/ethyl acetate 4:6) 
EXAMPLE 35: 
N-N-(2-Acetylthio-3-phenylpropanoyl)glycyl!-5-(ortho-methylphenyl)proline 
methyl ester 
The compound obtained in Preparation I is deprotected in accordance with 
the process described in Step b of Preparation G and the dipeptide 
obtained is coupled with 2-acetylthio-3-phenylpropanoic acid in accordance 
with the process of Preparation A. The white solid so obtained is 
chromatographed in an n-hexane/ethyl acetate mixture, 55:45. 
Yield: 58% 
Melting point: 97.degree. C. 
R.sub.f : 0.40 (n-hexane/ethyl acetate, 4:6) 
EXAMPLE 36: 
N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-5-(ortho-methylphenyl)proline 
The compound obtained in Example 35 is treated in accordance with the 
process of Example 3. A white solid is obtained. 
Yield : 63% 
Melting point: 110.degree. C. (decomposition) 
R.sub.f : 0.15 (dichloromethane/methanol/acetic acid, 9:0.7:0.25) 
Using analogous processes, the compounds of the following Examples are 
obtained: 
EXAMPLE 37: 
N-N-(2-Propanoylthio-3-phenylpropanoyl)glycyl!-5-(ortho-hydroxyphenyl)pro 
line 
EXAMPLE 38: N-N-(2-Benzoylthio-3-phenylpropanoyl)glycyl!-5-phenylproline 
EXAMPLE 39: 
N-N-2-Mercapto-3-(para-sulphamoylphenyl)propanoyl!glycyl!-5phenylproline 
EXAMPLE 40: 
N-N-2-Mercapto-3-(para-propylsulphamoylphenyl)propanoyl!glycyl!5-(meta-h 
ydroxyphenyl)proline 
EXAMPLE 41: 
N-N-2-Acetylthio-3-(para-sulphamoylphenyl)propanoyl!glycyl!-5-(meta-hydr 
oxyphenyl)proline cyclohexylmethyl ester 
EXAMPLE 42: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(meta-hydroxyph 
enyl)proline benzyl ester 
EXAMPLE 43: 
N-N-2-Mercapto-3-(para-chlorophenyl)propanoyl!glycyl!-2-(orthohydroxyphe 
nyl)imidazolidine-5-carboxylic acid 
EXAMPLE 44: 
N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-2-phenyloxazolidine-5-carboxyli 
c acid 
EXAMPLE 45: 
N-N-(2-Mercapto-3-phenylpropanoyl)glycyl!-2-(ortho-hydroxyphenyl)-thiazol 
idine-5-carboxylic acid 
EXAMPLE 46: 
N-N-2-Mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-2-(meta-hydroxyph 
enyl)hexahydropyrimidinyl-6-carboxylic acid 
EXAMPLE 47: 
N-N-(5R)-(2S)-2-mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!5-(meta- 
hydroxyphenyl)-L-proline 
The (5R)-5-(meta-hydroxyphenyl)-L-proline, obtained according to the 
preparation process described by J. Ezquerra et al. (Tetrahedron Letters, 
34 (39), (1993), 6317-6320), is treated under the conditions described in 
Preparation G, and coupled, according to the process described in 
Preparation A, with 
(2S)-2-acetylthio-3-(para-benzyloxycarbonyloxyphenyl)propanoic acid 
obtained in Preparation C. The so obtained ester is saponified as 
described in Example 18 to yield the title compound. Compounds of Examples 
48 to 53 are similarly obtained as described in Example 47. 
EXEMPLE 48: 
N-N-(5R)-(2S)-(2-mercapto-3-phenylpropanoyl)glycyl!-5-phenyl!-L-proline 
EXEMPLE 49 : 
N-N-(5R)-(2S)-(2-mercapto-3-phenylpropanoyl)glycyl!-5-(ortho-hydroxyphen 
yl)!-L-proline 
EXEMPLE 50: 
N-N-(5R)-(2S)-2-mercapto-3-(para-chlorophenyl)propanoyl!glycyl!-5(ortho 
-hydroxyphenyl)-L-proline 
EXEMPLE 51: 
N-N-(5R)-(2S)-2-mercapto-3-(para-aminophenyl)propanoyl!glycyl!-5phenyl! 
-L-proline 
EXEMPLE 52: 
N-N-(5S)-(2S)-2-mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!5-(meta- 
hydroxyphenyl!-D-proline 
EXEMPLE 53: 
N-N-(5R)-(2R)-2-mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!5-(meta- 
hydroxyphenyl!-L-proline 
EXEMPLE 54: 
N-N-(5S)-(2S)-2-mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(meta 
-hydroxyphenyl!-L-proline 
Step a: (2S)-5-(meta-hydroxyphenyl)-3,4-dihydro2H!pyrrole-2-carboxylic 
acid 
Compound obtained according to the protocol described by Gershon et al. (J. 
Med. Chem., (1965), 8, 877-881). 
Step b: (5S)-5-(meta-hydroxyphenyl)-L-proline 
The compound obtained in Step a is reduced (treatment by OH.sup.-, H.sup.+ 
and NaBH.sub.4) so as to yield a mixture of (2S, 5R) and (2S, 5S) isomers, 
which are then separated according to the process described by C. G. 
Overberger et al. (Macromolecules, (1972), 5 (4), 368-372). 
Step c : 
N-N-(5S)-(2S)-2-mercapto-3-para-hydroxyphenyl)propanoyl!glycyl!-5(meta-h 
ydroxyphenyl!-L-proline 
The title compound is obtained from the compound obtained at the preceding 
Step according to the preparation process described in Example 47. 
EXAMPLE 55: 
N-N-(5R)-(2S)-2-mercapto-3-(para-hydroxyphenyl)propanoyl!glycyl!-5-(meta 
-hydroxyphenyl!-L-proline 
Compound obtained according to the preparation process described in Example 
54, starting from 
(2R)-5-(meta-hydroxyphenyl)-3,4-dihydro2H!pyrrole-2-carboxylic acid. 
PHARMACOLOGICAL STUDY 
EXAMPLE A: Inhibitory effect in vitro on neutral endopeptidase (NEP) and 
peptidyl-dipeptidase A (ACE) 
The inhibitory properties of the compounds of the invention are measured 
using .sup.3 H!-D-Ala.sup.2 -Leu-encephalin as substrate for neutral 
endopeptidase, in accordance with the protocol described by Llorens et al. 
(Biochem. Biophys. Res. Commun., 96, (1980), 1710 sqq), and Z-Phe-His-Leu 
as substrate in the case of peptidyldipeptidase A in accordance with the 
protocol described in Biochem. Biophys. Acta, 206, (1970), 136-142. 
The results are given in Table I, which also gives the results obtained 
with N-(2- mercaptomethyl-3-phenyl-1-oxopropyl)glycine (thiorphan) which, 
although of very similar structure, exhibits an activity on neutral 
endopeptidase (NEP) only. 
TABLE I 
______________________________________ 
Inhibitory effect on neutral endopeptidase (NEP) 
and angiotensin conversion enzyme (ACE) 
COMPOUND IC.sub.50 (nM) NEP 
IC.sub.50 (nM) ACE 
______________________________________ 
Example 3 1.6 .+-. 0.3 
0.55 .+-. 0.05 
Example 5 1.1 .+-. 0.3 
0.50 .+-. 0.10 
Example 7 4.3 .+-. 0.3 
0.35 .+-. 0.05 
Example 10 3.4 .+-. 0.8 
4.2 .+-. 0.4 
Example 14 1.8 .+-. 0.4 
3.5 .+-. 0.5 
Example 16 26 .+-. 3 23 .+-. 3 
Example 18 1.6 .+-. 0.3 
0.7 .+-. 0.2 
Example 20 2.4 .+-. 0.8 
1.4 .+-. 0.7 
Example 22 6 .+-. 1 0.45 .+-. 0.05 
Example 24 1.2 .+-. 0.4 
0.90 .+-. 0.06 
Example 26 2.3 .+-. 0.3 
0.40 .+-. 0.05 
Example 28 2.5 .+-. 0.6 
2.20 .+-. 0.20 
Example 30 10 .+-. 2 8.2 .+-. 0.5 
Example 32 5.0 .+-. 0.5 
3.2 .+-. 0.4 
Example 34 3.1 .+-. 0.3 
5.2 .+-. 0.5 
Example 36 4.0 .+-. 0.6 
3.5 .+-. 0.6 
thiorphan 2.0 .+-. 0.4 
140 .+-. 13 
______________________________________ 
EXAMPLE B: Inhibitory effect in vivo on renal neutral endopeptidase (NEP) 
and pulmonary peptidyldipeptidase A (ACE) 
The compounds are administrated per os to mice in a single dose. Inhibition 
of both enzymes is measured during a time period from 1 hour to 16 hours 
by competitive experiments with specific radiolabelled markers for each 
enzyme. After i.v. administration of a radiolabelled ACE inhibitor 
(.sup.3 H!trandolaprilate) or a radiolabelled NEP inhibitor (.sup.3 
H!HACBOGIy), the animal is sacrificed and the lungs or the kidneys are 
removed. The organs are homogenized and the radioactivity associated to 
these homogenates is measured by liquid scintillation as described in the 
protocol by M. C. Fourni6-Zaluski et al. (J. Med. Chem., 37, (1994), 
1070-1083). 
By way of example, the compound described in Example 47 has provided the 
results shown in the following Table II: 
TABLE II 
______________________________________ 
Inhibition in vivo of renal NEP and pulmonary ACE 
(Compound of Example 47: dose administered p.o.: 
2.6 .times. 10.sup.-6 mol/kg, that is 1.5 mg/kg) 
time elapsed after 
% inhibition 
administration renal NEP 
pulmonary ACE 
______________________________________ 
1 h 75 .+-. 3 
90 .+-. 1 
2 h 70 .+-. 5 
86 .+-. 3 
4 h 74 .+-. 4 
87 .+-. 3 
8 h 60 .+-. 10 
73 .+-. 3 
16 h 48 .+-. 4 
20 .+-. 8 
______________________________________ 
EXAMPLE C: Anti-hypertensive effects 
The anti-hypertensive effect of the compounds of the invention is 
determined in vivo in the rat affected by a hypertension induced by the 
administration of DOCA salt (deoxycorticosterone acetate) and in the 
spontaneously hypertensive male rat (SHR), in accordance with the protocol 
described by Trapani et al. (J. Cardiovasc. Pharmacol., 14, (1989), 
419-424). In that test the compounds of the invention are shown to be 
powerful anti-hypertensives and to be non-toxic. 
By way of example, the compound described in Example 47 has provided, for 
the SHR rat, the results shown in the following Table III: 
TABLE III 
______________________________________ 
Study of the anti-hypertensive effect in the SHR rat 
(Administration p.o., single dose of 25 mg/kg/day; 
the animals are treated during 6 days, 
first administration Day 1, last administistration Day 6) 
Systolic blood pressure 
(mm Hg) 
Treated animals 
Control animals 
DAY (n = 10) (n = 10) 
______________________________________ 
0 210 .+-. 5 210 .+-. 5 
1 212 .+-. 3 195 .+-. 3* 
2 211 .+-. 1 189 .+-. 5* 
3 210 .+-. 2 183 .+-. 4* 
4 205 .+-. 2 184 .+-. 3* 
5 205 .+-. 1 182 .+-. 3* 
6 213 .+-. 2 185 .+-. 5* 
7 209 .+-. 4 189 .+-. 3 
8 212 .+-. 2 198 .+-. 5 
9 208 .+-. 2 203 .+-. 5 
10 214 .+-. 1 210 .+-. 3 
______________________________________ 
.quadrature.*:p &lt; 0.01 treatment 
EXAMPLE D: Pharmaceutical composition: tablets 
Formulation for the preparation of 1000 tablets each comprising 10 mg of 
active ingredient 
______________________________________ 
compound of Example 5 10 g 
lactose 50 g 
magnesium stearate 10 g 
wheat starch 20 g 
corn starch 10 g 
silica 5 g 
hydroxypropyl cellulose 5 g 
______________________________________