Novel mercapto-acylamino acids of the formula ##STR1## wherein Q is hydrogen or R.sup.7 CO--; PA1 R.sup.1 is lower alkyl, cyclolower alkyl, aryl or heteroaryl; PA1 R.sup.2 is hydrogen; lower alkyl; cyclolower alkyl; lower alkyl substituted with hydroxy, lower alkoxy, mercapto, lower alkylthio, aryl or heteroaryl; aryl; or heteroaryl; PA1 R.sup.3 is --OR.sup.5 or --NR.sup.5 R.sup.6 ; PA1 R.sup.4 and R.sup.9 are independently --(CH.sub.2).sub.q R.sup.8, provided that when R.sup.4 and R.sup.9 are both hydrogen, R.sup.2 is biphenylyl, phenoxyphenyl, phenylthiophenyl, naphthyl, heteroaryl, or lower alkyl substituted with hydroxy, lower alkoxy, mercapto or lower alkylthio; PA1 R.sup.5 and R.sup.6 are independently selected from the group consisting of hydrogen, lower alkyl, hydroxy lower alkyl, lower alkoxy lower alkyl and aryl lower alkyl, or R.sup.5 and R.sup.6 together with the nitrogen to which they are attached form a 5-7 membered ring; PA1 R.sup.7 is hydrogen, lower alkyl or aryl; PA1 R.sup.8 is hydrogen, hydroxy, lower alkoxy, mercapto, lower alkylthio, aryl or heteroaryl; PA1 n is 1 or 2; PA1 p is 0 or 1; PA1 q is 0, 1 or 2; and PA1 t is 0 or 1; and the pharmaceutically acceptable salts thereof useful in the treatment of cardiovascular disorders and pain conditions and combinations of mercapto-acrylamino acids and atrial natriuretic factors or angiotensin converting enzyme inhibitors useful for treating cardiovascular disorders are disclosed.

BACKGROUND OF THE INVENTION 
The present invention relates to mercapto-acylamino acids useful in the 
treatment of cardiovascular disorders and pain conditions. 
Cardiovascular disorders which may be treated with compounds of the present 
invention include hypertension, congestive heart failure, edema and renal 
insufficiency. 
Human hypertension represents a disease of multiple etiologies. Included 
among these is a sodium and volume dependent low renin form of 
hypertension. Drugs that act to control one aspect of hypertension will 
not necessarily be effective in controlling another. 
Enkephalin is a natural opiate receptor agonist which is known to produce a 
profound analgesia when injected into the brain ventricle of rats. It is 
also known in the art that enkephalin is acted upon by a group of enzymes 
known generically as enkephalinases, which are also naturally occurring, 
and is inactivated thereby. 
A variety of mercaptoacylamino acids are known as enkephalinase inhibitors 
useful as analgesics and in the treatment of hypertension. Most are alpha 
amino acids, however European Patent Application 136,883, published Apr. 
10, 1985, and U.S. Pat. No. 4,774,256 disclose, inter alia, compounds of 
the formula 
##STR2## 
wherein n is 1-15 and R.sub.2 and R.sub.3 are various aryl, arylalkyl and 
heteroarylalkyl groups. The compounds are disclosed as having 
enkephalinase inhibiting activity. 
It has recently been discovered that the heart secretes a series of peptide 
hormones called atrial natriuretic factors (ANF) which help to regulate 
blood pressure, blood volume and the excretion of water, sodium and 
potassium. ANF were found to produce a short-term reduction in blood 
pressure and to be useful in the treatment of congestive heart failure. 
See P. Needleman et al, "Atriopeptin: A Cardiac Hormone Intimately 
Involved in Fluid, Electrolyte and Blood-Pressure Homeostasis", N. Engl. 
J. Med., 314, 13 (1986) pp. 828-834, and M. Cantin et al in "The Heart as 
an Endocrine Gland", Scientific American, 254 (1986) pg. 7681. 
A class of drugs known to be effective in treating some types of 
hypertension is ACE inhibitors, which compounds are useful in blocking the 
rise in blood pressure caused by increases in vascular resistance and 
fluid volume due to the formation of angiotension II from angiotensin I. 
For a review of ACE inhibitors, see M. Wyvratt and A. Patchett, "Recent 
Developments in the Design of Angiotensin Converting Enzyme Inhibitors" in 
Med. Res. Rev. Vol. 5, No. 4 (1985) pp. 483-531. 
SUMMARY OF THE INVENTION 
Novel compounds of the present invention are represented by the formula 
##STR3## 
wherein Q is hydrogen or R.sup.7 CO--; 
R.sup.1 is lower alkyl, cyclolower alkyl, aryl or heteroaryl; 
R.sup.2 is hydrogen; lower alkyl; cyclolower alkyl; lower alkyl substituted 
with hydroxy, lower alkoxy, mercapto, lower alkylthio, aryl or heteroaryl; 
aryl; or heteroaryl; 
R.sup.3 is --OR.sup.5 or --NR.sup.5 R.sup.6 ; 
R.sup.4 and R.sup.9 are independently --(CH.sub.2).sub.q R.sup.8, provided 
that when R.sup.4 and R.sup.9 are both hydrogen, R.sup.2 is biphenylyl, 
phenoxyphenyl, phenylthiophenyl, naphthyl, heteroaryl, or lower alkyl 
substituted with hydroxy, lower alkoxy, mercapto or lower alkylthio; 
R.sup.5 and R.sup.6 are independently selected from the group consisting of 
hydrogen, lower alkyl, hydroxy lower alkyl, lower alkoxy lower alkyl and 
aryl lower alkyl, or R.sup.5 and R.sup.6 together with the nitrogen to 
which they are attached form a 5-7 membered ring; 
R.sup.7 is hydrogen, lower alkyl or aryl; 
R.sup.8 is hydrogen, hydroxy, lower alkoxy, mercapto, lower alkylthio, aryl 
or heteroaryl; 
n is 1 or 2; 
p is 0 or 1; 
q is 0, 1 or 2; and 
t is 0 or 1; 
and the pharmaceutically acceptable salts thereof. 
A preferred group of compounds of the present invention is that wherein t 
is zero, with compounds wherein p and t are both zero being more 
preferred. Another group of preferred compounds is that wherein R.sup.4 is 
hydrogen, hydroxy, methoxy, phenyl or benzyl. Still another preferred 
group is that wherein R.sup.2 is hydrogen or thienyl. Preferred amino acid 
portions of the compounds of formula I (i.e. the portion 
--NH--CH(R.sup.2)--CH(R.sup.4)--(CH.sub.2).sub.t --(CHR.sup.9).sub.p 
--COR.sup.3) are those wherein p and t are each 0, R.sup.2 is hydrogen and 
R.sup.4 is hydroxy or methoxy (e.g. isoserine or O-methyl isoserine); 
those wherein t is 1, p is 0, R.sup.2 is hydrogen and R.sup.4 is hydroxy 
(e.g. homo-isoserine); those wherein p and t are each 0, R.sup.2 is 
thienyl and R.sup.4 is hydrogen (e.g. .beta.-thienyl-.beta.-alanine); and 
those wherein p and t are each 0, R.sup.2 is hydrogen and R.sup.4 is 
phenyl or benzyl. 
Other preferred compounds of formula I are those wherein Q is hydrogen or 
acyl. Still other preferred compounds are those wherein R.sup.1 is phenyl 
or lower alkyl-substituted phenyl, for example tolyl. Yet another 
preferred group of compounds is that wherein R.sup.3 is hydroxy or lower 
alkoxy. A preferred value for n is 1. 
Especially preferred compounds of formula I are those wherein Q is hydrogen 
or acyl; R.sup.1 is phenyl or tolyl; n is 1; R.sup.2 is hydrogen or 
thienyl; R.sup.4 is hydrogen, hydroxy, methoxy, phenyl or benzyl; p is 0; 
and R.sup.3 is hydroxy or lower alkoxy. 
Examples of especially preferred compounds of formula I wherein n is 1 and 
p is zero are shown in the following Table 1: 
TABLE 1 
______________________________________ 
Compound t Q R.sup.1 
R.sup.2 R.sup.3 
R.sup.4 
______________________________________ 
a 0 H Ph H OH OH 
b 0 H Ph H OH Ph 
c 0 Ac Ph 3-Thienyl 
OMe H 
d 0 H Ph 3-Thienyl 
OH H 
e 1 Ac Ph H OMe OH 
f 0 Ac o-Tol H OEt OH 
g 0 Ac o-Tol H OEt Benzyl 
h 1 H Ph H OH OH 
i 0 H o-Tol H OH OH 
j 0 H o-Tol H OH OMe 
______________________________________ 
The invention also relates to the treatment of cardiovascular diseases with 
a combination of a mercapto-acylamino acid of the present invention and an 
atrial natriuretic factor (ANF) and with a combination of a 
mercapto-acylamino acid of the present invention and an angiotensin 
converting enzyme (ACE) inhibitor. 
Other aspects of the invention relate to pharmaceutical compositions 
comprising a mercapto-acylamino acid of this invention, alone or in 
combination with an ANF or an ACE inhibitor, and to methods of treatment 
of cardiovascular diseases comprising administering a mercapto-acylamino 
acid of this invention, alone or in combination with an ANF or an ACE 
inhibitor, to a mammal in need of such treatment. 
Still another aspect of the invention relates to a method of treating pain 
conditions by administering a mercapto-acylamino acid of this invention, 
thereby inhibiting the action of enkephalinase in a mammal and eliciting 
an analgesic effect. Analgesic pharmaceutical compositions comprising said 
mercapto-acylamino compounds are also contemplated. 
DETAILED DESCRIPTION 
As used herein, the term "lower alkyl" means straight or branched alkyl 
chains of 1 to 6 carbon atoms, and "lower alkoxy" similarly refers to 
alkoxy groups having 1 to 6 carbon atoms. Cyclolower alkyl means cyclic 
alkyl groups of 3 to 6 carbon atoms. 
"Aryl" means mono-cyclic or fused ring bicyclic carbocyclic aromatic groups 
having 6 to 10 ring members and "heteroaryl" means mono-cyclic or fused 
ring bicyclic aromatic groups having 5-10 ring members wherein 1-2 ring 
members are independently nitrogen, oxygen or sulfur, wherein the carbon 
ring members of the aryl and heteroaryl groups are substituted by zero to 
three substituents selected from the group consisting of lower alkyl, 
hydroxy, halogeno, lower alkoxy, trifluoromethyl, phenyl, phenoxy or 
phenylthio. Examples of carbocyclic aryl groups are phenyl, 
.alpha.-naphthyl and .beta.-naphthyl, and examples of heterocyclic aryl 
groups are furyl, thienyl, pyrrolyl, benzofuryl, benzothienyl, indolyl and 
pyridyl. All positional isomers, e.g. 2-pyridyl, 3-pyridyl, are 
contemplated. 
"Halo" refers to fluorine, chlorine, bromine or iodine radicals. 
Certain compounds of the invention are acidic e.g., those compounds which 
possess a carboxyl group. These compounds form pharmaceutically acceptable 
salts with inorganic and organic bases. Examples of such salts are the 
sodium, potassium, calcium, aluminum, gold and silver salts. Also included 
are salts formed with pharmaceutically acceptable amines such as ammonia, 
alkyl amines, hydroxyalkylamines, N-methylglucamine and the like. 
The salts may be formed by conventional means, as by reacting the free acid 
or base forms of the product with one or more equivalents of the 
appropriate base or acid in a solvent or medium in which the salt is 
insoluble, or in a solvent such as water which is then removed in vacuo or 
by freeze-drying or by exchanging the cations of an existing salt for 
another cation on a suitable ion exchange resin. 
Compounds of formula I have at least one asymmetrical carbon atom and 
therefore include various stereoisomers. The invention includes all such 
isomers both in pure form and in admixture, including reacemic mixtures. 
An aspect of the present invention described above relates to the 
combination of a compound of formula I with an ANF. As indicated by 
Needleman et al., a number of ANF have been isolated so far, all having 
the same core sequence of 17 amino acids within a cysteine disulfide 
bridge, but having different N-termini lengths. These peptides represent 
N-terminal truncated fragments (21-48 amino acids) of a common 
preprohormone (151 and 152 amino acids for man and rats, respectively). 
Human, porcine and bovine carboxy-terminal 28-amino acid peptides are 
identical and differ from similar peptides in rats and mice in that the 
former contain a methionine group at position 12 while the latter contain 
iscleucine. Various synthetic analogs of naturally occuring ANF's also 
have been found to have comparable biological activity. Examples of ANFs 
contemplated for use in this invention are .alpha. human AP 21 
(atriopeptin I), .alpha. human AP 28, .alpha. human AP 23 (atriopeptin II 
or APII), .alpha. human AP 24, .alpha. human AP 25, .alpha. human AP 26, 
.alpha. human AP 33, and the corresponding rat sequence of each of the 
above wherein Met 12 is lle. See Table II for a comparison of the 
peptides. 
3 TABLE II 
##STR4## 
##STR5## 
##STR6## 
*Ile is the rat peptide 
Another aspect of the invention is the administration of a combination of 
an ACE inhibitor and a compound of formula I. 
Examples of ACE inhibitors are those disclosed in the article by Wyvratt et 
al., cited above, and in the following U.S. patents: U.S. Pat. Nos. 
4,105,776, 4,468,519, 4,555,506, 4,374,829, 4,462,943, 4,470,973, 
4,470,972, 4,350,704, 4,256,761, 4,344,949, 4,508,729, 4,512,924, 
4,410,520 and 4,374,847, all incorporated herein by reference; and the 
following foreign patents or published patent applications: 
British Specification No. 2095682 published Oct. 6, 1982 discloses 
N-substituted-N-carboxyalkyl aminocarbonyl alkyl glycine derivatives which 
are said to be angiotensin converting enzyme inhibitors and have the 
formula 
##STR7## 
either (A) R.sup.b and R.sub.9.sup.b are OH, 1-6C alkoxy, 2-6C alkenyloxy, 
di(1-6C alkyl)amino-(1-6C) alkoxy, 1-6C hydroxyalkoxy, 
acylamino-(1-6C)alkoxy, acyloxy-(1-6C)alkoxy, aryloxy, 
aryloxy-(1-6C)alkoxy, NH.sub.2, mono- or di-(1-6C alkyl)amino, 
hydroxyamino or aryl-(1-6C)alkylamino; 
R.sub.1.sup.b -R.sub.5.sup.b, R.sub.7.sup.b and R.sub.8.sup.b are 1-20C 
alkyl, 2-20C alkenyl, 2-20C alkynyl, aryl, aryl-(1-6C) alkyl having 7-12C 
or heterocyclyl-(1-6C)alkyl having 7-12C; 
R.sub.6.sup.b is cycloalkyl, polycycloalkyl, partly saturated cycloalkyl or 
polycycloalkyl, cycloalkyl-(1-6C)alkyl having 3-20C, 6-10C aryl, 
aryl-(1-6C)alkyl, aryl-(2-6C)alkenyl or aryl-(2-6C) alkynyl; or 
R.sub.2.sup.b and R.sub.3.sup.b together with the C and N atoms to which 
they are attached or R.sub.3.sup.b and R.sub.5.sup.b together with the N 
and C atoms to which they are attached form an N-heterocycle containing 
3-5C or 2-4C and a S atom; 
all alkyl, alkenyl and alkynyl are optionally substituted by OH, 1-6C 
alkoxy, thio(sic), 1-6C alkylthio, NH.sub.2, mono-or di(1-6C alkyl)amino, 
halogen or NO.sub.2 ; 
all `cycloalkyl` groups (including poly and partially unsaturated) are 
optionally substituted by halogen, 1-6C hydroxyalkyl, 1-6C alkoxy, 
amino-(1-6C alkyl)amino, di-(1-6C alkyl)amino, SH, 1-6C alkylthio, 
NO.sub.2 or CF.sub.3 ; and aryl groups are optionally substituted by OH, 
1-6C alkoxy, NH.sub.2, mono- or di-(1-6C alkyl) amino, SH, 1-6C alkylthio, 
1-6C hydroxyalkyl, 1-6C aminoalkyl, 1-6C thioalkyl, NO.sub.2, halogen, 
CF.sub.3, OCH.sub.2 O, ureido or guanidino; or 
(B) R.sup.b and R.sub.9.sup.b are H or 1-6C alkoxy; 
R.sub.1.sup.b and R.sub.2.sup.b are H, 1-6C alkyl, aryl-(1-6C) alkyl having 
7-12C or heterocyclyl-(1-6C) alkyl having 6-12C; R.sub.3.sup.b 
-R.sub.5.sup.b, R.sub.7.sup.b and R.sub.8.sup.b are H or 1-6C alkyl; 
R.sub.6.sup.b is cycloalkyl, polycycloalkyl, partly saturated cycloalkyl or 
polycycloalkyl, cycloalkyl-(1-6C) alkyl having 3-20C, aryl or aryl-(1-6C) 
alkyl; and 
aryl has 6-10C and is optionally substituted by 1-6C alkyl, 2-6C alkenyl, 
2-6C alkynyl, OH, 1-6C alkoxy, NH.sub.2, mono-or di-(1-6C alkyl) amino, 
SH, 1-6C alkylthio, 1-6C hydroxyalkyl, 1-6C aminoalkyl, 1-6C thioalkyl, 
NO.sub.2, halogen, CF.sub.3, OCH.sub.2 O, ureido or guanidino; 
European Patent Application 0 050 800 published May 5, 1982 discloses 
carboxyalkyl dipeptides derivatives which are said to be angiotensin 
converting enzyme inhibitors and have the formula 
##STR8## 
or a pharmaceutically acceptable salt thereof, wherein R.sup.c and 
R.sup.6c are the same or different and are hydroxy, lower alkoxy, lower 
alkenyloxy, dilower alkylamino lower alkoxy, acylamino lower alkoxy, 
acyloxy lower alkoxy, aryloxy, aryllower alkoxy, amino, lower alkylamino, 
dilower alkylamino, hydroxyamino, aryllower alkylamino, or substituted 
aryloxy or substituted aryllower alkoxy wherein the substituent is methyl, 
halo or methoxy; R.sup.1c is hydrogen, alkyl of from 1 to 10 carbon atoms, 
substituted lower alkyl wherein the substituent is hydroxy, lower alkoxy, 
aryloxy, substituted aryloxy, heteroaryloxy, substituted heteroaryloxy, 
amino, lower alkylamino, diloweralkylamino, acylamino, arylamino, 
substituted arylamino, guanidino, imidazolyl, indolyl, lower alkylthio, 
arylthio, substituted arylthio, carboxy, carbamoyl, lower alkoxy carbonyl, 
aryl, substituted aryl, aralkyloxy, substituted aralkyloxy, aralkylthio or 
substituted aralkylthio, wherein the aryl or heteroaryl portion of said 
substituted aryloxy, heteroaryloxy, arylamino, arylthio, aryl, aralkyloxy, 
aralkylthio group is substituted with a group selected from halo, lower 
alkyl, hydroxy, lower alkoxy, amino, aminomethyl, carboxyl, cyano, or 
sulfamoyl; R.sup.2c and R.sup.7c are the same or different and are 
hydrogen or lower alkyl; R.sup.3c is hydrogen, lower alkyl, phenyl lower 
alkyl, aminoethylphenyl lower alkyl, hydroxyphenyl lower alkyl, hydroxy 
lower alkyl, acylamino lower alkyl, amino lower alkyl, dimethylamino lower 
alkyl, guanidino lower alkyl, imidazolyl lower alkyl, indolyl lower alkyl, 
or lower alkyl thio lower alkyl; R.sup.4c and R.sup.5c are the same or 
different and are hydrogen, lower alkyl or Z.sup.c, or R.sup.4c and 
R.sup.5c taken together form a group represented by Q.sup.c, U.sup.c, 
V.sup.c, Y.sup.c, D.sup.c or E.sup.c, wherein; 
Z.sup.c is 
##STR9## 
wherein X.sup.1c and X.sup.2c independent of each other are O, S or 
CH.sub.2, R.sup.8c and R9c independent of each other are lower alkyl, 
lower alkenyl, lower alkynyl, cycloalkyl having 3 to 8 carbon atoms, 
hydroxy lower alkyl, or --(CH.sub.2).sub.n.sup.c Ar.sup.c, wherein n.sup.c 
is 0, 1, 2 or 3 and Ar.sup.c is unsubstituted or substituted phenyl, 
furyl, thienyl or pyridyl, wherein said substituted phenyl, furyl, thienyl 
or pyridyl groups are substituted with at least one group that is 
independently selected from C.sub.1 to C.sub.4 alkyl, lower alkoxy, lower 
alkylthio, halo, CF.sub.3 and hydroxy, or R.sup.8c and R.sup.9c taken 
together form a bridge W.sup.c, wherein W.sup.c is a single bond or a 
methylene bridge or a substituted methylene bridge when at least one of 
X.sup.1c and X.sup.2c is methylene, or W.sup.c is an alkylene or 
substituted alkylene bridge having 2 or 3 carbon atoms, said substituted 
methylene bridge or said substituted alkylene bridge having one or two 
substituents selected from lower alkyl, aryl and aryl lower alkyl groups, 
and p.sup.c is 0, 1 or 2; with the proviso that at least one of R.sup.4c 
and R.sup.5c is Z.sup.c, with the proviso that if R.sup.4c is Z.sup.c and 
p.sup.c is 0 then X.sup.1c and X.sup.2c must both be methylene, and with 
the proviso that if X.sup.1c and X.sup.2c are both methylene then R.sup.8c 
and R.sup.9c must form an alkylene bridge W.sup.c ; 
Q.sup.c is 
##STR10## 
wherein R.sup.8c, R.sup.9c, X.sup.1c and X.sup.2c are as defined above, 
p.sup.c is 0, 1 or 2, q.sup.c is 0, 1 or 2, with the proviso that the sum 
of p.sup.c and q.sup.c must be 1, 2 or 3, with the proviso that if p.sup.c 
is 0 then X.sup.1c and X.sup.2c must be methylene, and with the proviso 
that if X.sup.1c and X.sup.2c are methylene then R.sup.8c and R.sup.9c 
taken together form a bridge W.sup.c, wherein W.sup.c is as defined above; 
V.sup.c is 
##STR11## 
wherein R.sup.8c, R.sup.9c, X.sup.1c and X.sup.2c are as defined above, 
p.sup.c is 0, 1 or 2 and q.sup.c is 0, 1 or 2, with the proviso that the 
sum of p.sup.c and q.sup.c is 1, 2 or 3, with the proviso that if X.sup.1c 
and X.sup.2c are CH.sub.2 then R.sup.8c and R.sup.9c taken together form a 
bridge W.sup.c, wherein W.sup.c is as defined above; 
U.sup.c is 
##STR12## 
wherein W.sup.c is as defined above (except that W.sup.c may also be a 
methylene bridge when X.sup.1c and X.sup.2c are oxygen or sulfur), 
X.sup.1c and X.sup.2c are as defined above, p.sup.c is 0, 1 or 2, q.sup.c 
is 0, 1 or 2, with the proviso that the sum of p.sup.c and q.sup.c is 1 or 
2, and with the proviso that if p.sup.c is 0, X.sup.1c must be CH.sub.2 ; 
Y.sup.c is 
##STR13## 
wherein G.sup.c is oxygen, sulfur or CH.sub.2, a.sup.c is 2, 3 or 4 and 
b.sup.c is 1, 2, 3, 4 or 5, with the proviso that the sum of a.sup.c and 
b.sup.c is 5, 6 or 7 or G.sup.c is CH.sub.2, a.sup.c is 0, 1, 2 or 3, 
b.sup.c is 0, 1, 2 or 3 with the proviso that the sum of a.sup.c and 
b.sup.c is 1, 2 or 3, with the proviso that the sum of a.sup.c and b.sup.c 
may be 1, 2 or 3 only if R.sup.1c is lower alkyl substituted with 
aralkylthio or aralkyloxy; 
D.sup.c is 
##STR14## 
wherein F.sup.c is O or S, j.sup.c is 0, 1 or 2 and k.sup.c is 0, 1 or 2, 
with the proviso that the sum of j.sup.c and k.sup.c must be 1, 2 or 3, 
and m.sup.c is 1, 2 or 3 and t.sup.c is 1, 2 or 3, with the proviso that 
the sum of m.sup.c and t.sup.c must be 2, 3 or 4; 
E.sup.c is 
##STR15## 
wherein L.sup.c is O or S, u.sup.c is 0, 1 or 2 and v.sup.c is 0, 1 or 2, 
with the proviso that the sum of u.sup.c and v.sup.c must be 1 or 2, and 
h.sup.c is 1 or 2 and s.sup.c is 1 or 2, with the proviso that the sum of 
h.sup.c and s.sup.c must be 2 or 3; 
European Patent Application 0 079 522 published May 25, 1983 discloses 
N-carboxymethyl(amidino) lysyl-proline compounds which are said to be 
angiotensin converting enzyme inhibitors and have the formula where 
##STR16## 
wherein: R.sup.d and R.sup.2d are independently hydrogen; loweralkyl; 
aralkyl; or aryl; 
R.sup.1d is hydrogen; branched or straight chain C.sub.1-12 alkyl and 
alkenyl; C.sub.3 -C.sub.9 cycloalkyl and benzofused alkyl; substituted 
loweralkyl where the substituents are halo, hydroxy loweralkoxy, aryloxy, 
amino, mono- or diloweralkylamino, acylamino, arylamino, guanidino, 
mercapto, loweralkylthio, arylthio, carboxy, carboxamido, or 
loweralkoxycarbonyl; aryl; substituted aryl where the substituents are 
loweralkyl, loweralkoxy, or halo; arloweralkyl; arloweralkenyl; 
heteroarloweralkyl; heteroarloweralkenyl; substituted arloweralkyl, 
substituted arloweralkenyl, substituted heteroarloweralkyl, or substituted 
heteroarloweralkenyl where the aryl and heteroaryl substituents are halo, 
dihalo, loweralkyl, hydroxy, loweralkoxy, amino, aminoloweralkyl, 
acylamino, mono- or diloweralkylamino, carboxyl, haloloweralkyl, nitro, 
cyano, or sulfonamido, and where the loweralkyl portion of arloweralkyl 
may be substituted by amino, acylamino, or hydroxyl; 
##STR17## 
where: X.sup.d and Y.sup.d taken together are --CH.sub.2 --CH.sub.2 --: 
##STR18## 
R.sup.4d is hydrogen; loweralkyl; aryl; substituted aryl; R.sup.5d is 
hydrogen; loweralkyl; aryl or substituted aryl; 
n.sup.d is 1 to 3; 
W.sup.d is absent; --CH.sub.2 --; 
##STR19## 
Z.sup.d is --(CH.sub.2).sub.m.sup.d, where m.sup.d is 0 to 2, provided 
that m.sup.d may not be 0 and W.sup.d may not be absent at the same time; 
and 
R.sup.6d is hydrogen; loweralkyl; halo; or OR.sup.4d ; 
R.sup.2d is --(CH.sub.2).sub.r.sup.d --B.sup.d --(CH.sub.2).sub.s.sup.d 
--NR.sup.7d R.sup.15d where 
r.sup.d and s.sup.d are independently 0 to 3; 
B.sup.d is absent; --O--; --S--; or --NR.sup.8d ; 
where R.sup.8d is hydrogen; loweralkyl; or alkanoyl; or aroyl; and 
R.sup.7d is 
##STR20## 
where R.sup.9d is loweralkyl; aralkyl; aryl; heteroaryl; or 
heteroarloweralkyl and these groups substituted by hydroxy, lower alkoxy 
or halo; carboxyl; carboxamido; nitromethenyl. 
R.sup.10d is hydrogen; loweralkyl; aryl; or amidino; 
R.sup.11d is hydrogen; loweralkyl; cyano; amidino; aryl; aroyl; 
loweralkanoyl; 
##STR21## 
R.sup.12d is hydrogen; loweralkyl; halo; aralkyl; amino; cyano; mono- or 
diloweralkylamino; or OR.sup.4d ; 
R13d is hydrogen; loweralkyl; or aryl; 
R15d is hydrogen; lower alkyl; aralkyl; or aryl; 
##STR22## 
constitute a basic heterocycle of 5 or 6 atoms or benzofused analogs 
thereof and optionally containing 1-3 N atoms, an oxygen, a sulfur, an 
S.dbd.O, or an SO.sub.2 group optionally substituted by amino, lower alkyl 
amino, diloweralkyl amino, lower alkoxy, or aralkyl groups; 
R.sup.3d is C.sub.3-8 cycloalkyl and benzofused C.sub.3-8 cycloalkyl; 
perhydrobenzofused C.sub.3-8 cycloalkyl; aryl; substituted aryl; 
heteraryl; substituted heteroaryl; 
R.sup.14d is hydrogen or loweralkyl; and, a pharmaceutically acceptable 
salt thereof; 
European Patent 79022 published May 18, 1983 discloses N-amino 
acyl-azabicyclooctane carboxylic acid derivatives which have the formula 
##STR23## 
hydrogen atoms at ring positions 1 and 5 are cis to each other and the 
3-carboxy group has the endo orientation; 
R.sub.1.sup.e is H, allyl, vinyl or the side chain of an optionally 
protected naturally occurring .alpha.-amino acid; 
R.sub.2.sup.e is H, 1-6C alkyl, 2-6C alkenyl or aryl(1-C alkyl); 
Y.sup.e is H or OH and Z.sup.e is H, or Y.sup.e and Z.sup.e together 
oxygen; 
X.sup.e is 1-6C alkyl, 2-6C alkenyl, 5-9C cycloalkyl, 6-12C aryl 
(optionally substituted by one to three 1-4C alkyl or alkoxy, OH, halo, 
nitro, amino (optionally substituted by one or two 1-4C alkyl), or 
methylenedioxy) or indol-3-yl); 
European Patent 46953 published Mar. 10, 1982 discloses N-amino 
acyl-indoline and tetrahydro isoquinoline carboxylic acids which are 
angiotensin coverting enzyme inhibitors and have the formula 
##STR24## 
n.sup.f is 0 or 1; 
##STR25## 
is a benzene or cyclohexane ring: R.sub.1.sup.f and R.sub.2.sup.f are 
each 1-6C alkyl, 2-6C alkenyl, 5-7C cycloalkyl, 5-7C cycloalkenyl, 7-12C 
cycloalkylalkyl, optionally partially hydrogenated 6-10C aryl, 7-14C 
aralkyl or 5-7 membered monocyclic or 8-10 membered bicyclic heterocyclyl 
containing 1 or 2 S or O and/or 1-4N atoms; all R.sub.1.sup.f and 
R.sub.2.sup.f groups are optionally substituted, R.sub.3.sup.f is H, 1-6C 
alkyl, 2-6C alkenyl or 7-14C aralkyl. 
The following Table III lists ACE inhibitors preferred for use in the 
combination of this invention. 
TABLE III 
__________________________________________________________________________ 
PREFERRED ACE INHIBITORS 
__________________________________________________________________________ 
##STR26## 
R R.sub.1 
R.sub.2 R.sub.3 
__________________________________________________________________________ 
spirapril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
Et 
CH.sub.3 
##STR27## 
enalapril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
Et 
CH.sub.3 
prolyl 
ramipril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
Et 
CH.sub.3 
##STR28## 
perindopril 
CH.sub.3 CH.sub.2 CH.sub.2 
Et 
CH.sub.3 
##STR29## 
indolapril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
Et 
CH.sub.3 
##STR30## 
lysinopril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
H NH.sub.2 (CH.sub.2).sub.4 
prolyl 
quinapril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
Et 
CH.sub.3 
##STR31## 
pentopril (NH = CH.sub.2) 
CH.sub.3 Et 
CH.sub.3 
##STR32## 
cliazapril 
C.sub.6 H.sub.5 CH.sub.2 CH.sub.2 
H 
##STR33## 
##STR34## 
__________________________________________________________________________ 
##STR35## 
R R.sub.2 
__________________________________________________________________________ 
captopril H prolyl 
zofenopril 
C.sub.6 H.sub.5 CO 
##STR36## 
pivalopril 
##STR37## 
##STR38## 
__________________________________________________________________________ 
##STR39## 
R R.sup.1 R.sup.2 
__________________________________________________________________________ 
fosinopril 
C.sub.6 H.sub.5(CH.sub.2).sub.4 
##STR40## C.sub.6 H.sub.5 
__________________________________________________________________________ 
Compounds of the present invention can be made by methods well known to 
those skilled in the art. A typical general procedure is to combine a 
propionic acid, II, with an amino ester or amino amide, III, under typical 
peptide coupling conditions, using, for example, a coupling agent such as 
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC): 
##STR41## 
Alternatively, the propionic acid (II) can be converted by known methods 
(e.g. treatment with thionyl chloride) to the corresponding acid chloride 
(IV), and the acid chloride can be reacted with the amino acid, amino 
ester or amino amide in the presence of a base such as triethylamine to 
obtain a compound of formula I: 
##STR42## 
In the reaction schemes above, Q is typically acetyl or benzoyl and R.sup.3 
is typically alkoxy or benzyloxy. To obtain compounds of formula I wherein 
Q is hydrogen and R.sup.3 is OH, the sulfur and hydroxy protecting groups 
can be removed by conventional means, e.g. removal of an acetyl or benzoyl 
group can be accomplished by treating with sodium hydroxide, then 
acidifying with HCl. 
For compounds of formula III wherein R.sup.4 is hydroxy, it may be 
desirable to protect such a group during the reaction, e.g. with a 
t-butoxycarbonyl or benzyloxycarbonyl group. 
Compounds of formula II-IV are known in the art or can be prepared by 
methods well known in the art. 
We have found that the novel compounds of the present invention are 
effective in treating cardiovascular disorders such as congestive heart 
failure, edema, renal insufficiency and various types of hypertension, 
particularly volume expanded hypertension. These novel compounds enhance 
both the magnitude and duration of the antihypertensive and natriuretic 
effects of endogenous ANF. Administration of a combination of a 
mercapto-acylamino acid and an ACE inhibitor provides an antihypertensive 
and anti-congestive heart failure effect greater than either the 
mercapto-acylamino acid or ACE inhibitor alone. Administration of a 
combination of a mercapto-acylamino acid of formula I and an exogenous ANF 
or ACE inhibitor is therefore particularly useful in treating hypertension 
or congestive heart failure. 
In addition to the compound aspect, the present invention therefore also 
relates to treating cardiovascular disorders with a mercapto-acylamino 
acid of formula I or with a mercapto-acylamino acid of formula I in 
combination with an ANF or an ACE inhibitor, which methods comprise 
administering to a mammal in need of such treatment an amount of the 
mercapto-acylamino acid effective to treat hypertension or congestive 
heart failure or an amount of a combination of a mercapto-acylamino acid 
and ANF or ACE inhibitor effective to treat hypertension or congestive 
heart failure. The drug or combination of drugs is preferably administered 
in a pharmaceutically acceptable carrier, e.g. for oral or parenteral 
administration. The combinations of drugs may be co-administered in a 
single composition, or components of the combination therapy may be 
administered separately. Where the components are administered separately, 
any convenient combination of dosage forms may be used, e.g. oral 
mercapto-acylamino acid/oral ANF, oral mercaptoacylamino acid/parenteral 
ACE inhibitor, parenteral mercapto-acylamino acid/oral ANF, parenteral 
mercapto-acylamino acid/parenteral ACE inhibitor. 
When the components of a combination of a mercapto-acylamino acid and an 
ANF are administered separately, it is preferred that the 
mercapto-acylamino acid be administered first. 
The present invention also relates to a pharmaceutical composition 
comprising a mercapto-acylamino acid for use in treating hypertension or 
congestive heart failure, to a pharmaceutical composition comprising both 
a mercapto-acylamino acid and an ANF and to a pharmaceutical composition 
comprising both a mercapto-acylamino acid and an ACE inhibitor. 
The antihypertensive effect of mercapto-acylamino acids was determined 
according to the following procedure: 
Male Sprague Dawley rats weighing 100-150 g were anesthetized with ether 
and the right kidney was removed. Three pellets containing DOC acetate 
(desoxycorticosterone acetate, DOCA, 25 mg/pellet) were implanted 
subcutaneously. Animals recovered from surgery, were maintained on normal 
rat chow and were allowed free access to a fluid of 1% NaCl and 0.2% KCI 
instead of tap water for a period of 17-30 days. This procedure results in 
a sustained elevation in blood pressure and is a slight modification of 
published procedures (e.g. Brock et al., 1982) that have been used to 
produce DOCA salt hypertension in the rat. 
On the day of study, animals were again anesthetized with ether and the 
caudal artery was cannulated for blood pressure measurement. Patency of 
the caudal artery cannula was maintained with a continuous infusion of 
dextrose in water at a rate of 0.2 ml/hr. Animals were placed into 
restraining cages where they recovered consciousness. Blood pressure was 
measured from caudal artery catheter using a Statham pressure transducer 
attached to a Beckman oscillographic recorder. In addition, a 
cardiovascular monitoring device (Buxco Electronics, Inc.) and a digital 
computer were used to calculate average blood pressures. 
After an equilibration period of at least 1.5 hr., animals were dosed 
subcutaneously (1 ml/kg) with vehicle (methylcellulose, hereinafter MC) or 
mercapto-acylamino acid and blood pressure was monitored for the next 4 
hours. 
A similar procedure can be used to determine the effect of 
mercaptoacylamino acids in combination with ACE inhibitors. 
The antihypertensive effect of mercapto-acylamino acids in combination with 
ANF can be determined according to the following procedures: 
Male spontaneously hypertensive rats (SHR), 16-18 weeks old, 270-350 g, are 
anesthetized with ether and the abdominal aorta is cannulated through the 
tail artery. The animals are then placed into restrainers to recover from 
anesthesia (in less than 10 min.) and remain inside throughout the 
experiments. Through a pressure transducer (Gould P23 series) analog blood 
pressure signals are registered on a Beckman 612 recorder. A Buxco digital 
computer is used to obtain mean arterial pressures. Patency of the 
arterial cannula is maintained with a continuous infusion of 5% dextrose 
at 0.2 ml/hr. Animals are allowed a 90-min equilibration period. The 
animals first undergo a challenge with an ANF such as atriopeptin II (AP 
II) or AP28 30 )g/kg iv and at the end of 60 min. are treated with drug 
vehicle or a mercapto-acylamino acid subcutaneously. A second ANF 
challenge is administered 15 min. later and blood pressure is monitored 
for the next 90 min. 
The antihypertensive effect in SHR of mercapto-acylamino acids and ACE 
inhibitors, alone and in combination, can be determined as follows: 
Animals are prepared for blood pressure measurement as described above. 
After stabilization, animals are dosed subcutaneously or orally with test 
drugs or placebo and blood pressure is monitored for the next 4 hr. 
The compounds having structural formula I have also been found to inhibit 
the activity of enzymes designated enkephalinases. The compounds are 
particularly useful for the inhibition of enkephalinase A, which is 
derived from the striata of both rats and humans. In in vitro tests, using 
test procedures for enkephalinase A inhibition well known to those skilled 
in the art, selected compounds having structural formula I have been found 
to inhibit the activity of the aforementioned enzyme. Therefore, the 
present invention also relates to a method of inhibiting the action of 
enkephalinases in a mammal thereby to elicit an analgesic effect with a 
compound of formula I, and to analgesic pharmaceutical compositions 
comprising compounds of formula I. 
The compositions of this invention comprise a mercapto-acylamino acid or a 
mercaptoacylamino acid and an ANF or a mercapto-acylamino acid and an ACE 
inhibitor in combination with a pharmaceutically acceptable carrier for 
administration to mammals. A variety of pharmaceutical forms is suitable, 
preferably for oral or parenteral administration, although mechanical 
delivery systems such as transdermal dosage forms are also contemplated. 
The daily dose of the compound or combinations of this invention for 
treatment of hypertension or congestive heart failure is as follows: for 
mercaptoacylamino acids alone the typical dosage is 1 to 100 mg/kg of 
mammalian weight per day administered in single or divided dosages; for 
the combination of mercapto-acylamino acid and an ANF, the typical dosage 
is 1 to 100 mg of mercapto-acylamino acid/kg mammalian weight per day in 
single or divided dosages plus 0.001 to 0.1 mg ANF/kg of mammalian weight 
per day, in single or divided dosages, and for the combination of 
mercapto-acylamino acid and an ACE inhibitor, the typical dosage is 1 to 
100 mg of mercapto-acylamino acid/kg mammalian weight per day in single or 
divided dosages plus 0.1 to 30 mg ACE inhibitor/kg of mammalian weight per 
day in single or divided dosages. The exact dose of any component or 
combination to be administered is determined by the attending clinician 
and is dependent on the potency of the compound administered, the age, 
weight, condition and response of the patient. 
Generally, in treating humans having hypertension or congestive heart 
failure, the compounds or combinations of this invention may be 
administered to patients in a dosage range as follows: for treatment with 
mercapto-acylamino acids alone, about 10 to about 500 mg per dose given 1 
to 4 times a day, giving a total daily dose of about 10 to 2000 mg per 
day; for the combination of mercaptoacylamino acid and ANF, about 10 to 
about 500 mg mercapto-acylamino acid per dose given 1 to 4 times a day and 
about 0.001 to about 1 mg ANF given 1 to 6 times a day (total daily dosage 
range of 10 to 2000 mg day and .001 to 6 mg/day, respectively); and for 
the combination of a mercapto-acylamino acid and an ACE inhibitor, about 
10 to about 500 mg mercaptoacylamino acid per dose given 1 to 4 times a 
day and about 5 to about 50 mg ACE inhibitor given 1 to 3 times a day 
(total daily dosage range of 10 to 2000 mg/day and 5 to 150 mg/day, 
respectively). Where the components of a combination are administered 
separately, the number of doses of each component given per day may not 
necessarily be the same, e.g. where one component may have a greater 
duration of activity, and will therefore need to be administered less 
frequently. 
To produce an analgesic effect, compounds of this invention will be 
administered in a dosage range of from about 1 to about 100 mg/kg. The 
doses are to be administered at intervals of from 3 to 8 hours. However, 
the quantity and frequency of dosage will depend upon such factors as the 
severity of the pain, the general physical condition of the patient, the 
age and weight of the patient, and other factors recognized by the skilled 
clinician. 
Typical oral formulations include tablets, capsules, syrups, elixirs and 
suspensions. Typical injectable formulations include solutions and 
suspensions. 
The typical acceptable pharmaceutical carriers for use in the formulations 
described above are exemplified by: sugars such as lactose, sucrose, 
mannitol and sorbitol, starches such as cornstarch, tapioca starch and 
potato starch; cellulose and derivatives such as sodium carboxymethyl 
cellulose, ethyl cellulose and methyl cellulose; calcium phosphates such 
as dicalcium phosphate and tricalcium phosphate; sodium sulfate; calcium 
sulfate; polyvinylpyrrolidone, polyvinyl alcohol; stearic acid; alkaline 
earth metal stearates such as magnesium stearate and calcium stearate, 
stearic acid, vegetable oils such as peanut oil, cottonseed oil, sesame 
oil, olive oil and corn oil; non-ionic, cationic and anionic surfactants; 
ethylene gylcol polymers; betacyclodextrin; fatty alcohols and hydrolyzed 
cereal solids; as well as other nontoxic compatible fillers, binders, 
disintegrants, buffes, perservatives, antioxidants, lubricants, flavoring 
agents, and the like commonly used in pharmaceutical formulations. 
Since the present invention relates to treatment of hypertension or 
congestive heart failure with a combination of active ingredients wherein 
said active ingredients may be administered separately, the invention also 
relates to combining separate pharmaceutical compositions in kit form. 
That is, two kits are contemplated, each combining two separate units: a 
mecapto-acylamino acid pharmaceutical composition and an ANF 
pharmaceutical composition in one kit and a mercaptoacylamino acid 
pharmaceutical composition and an ACE inhibitor pharmaceutical composition 
in a second kit. The kit form is particularly advantageous when the 
separate components must be administered in different dosage forms (e.g. 
oral and parenteral) or are administered at different dosage intervals.

Following are examples of procedures for preparing compounds of formula I. 
PREATION 1 
(S)-ISOSERINE BENZYL ESTER, HYDROCHLORIDE 
At 0.degree.-5.degree., add thionyl chloride (11.0 ml) dropwise to 
N-(4-methoxybenzyloxycarbonyl)-(S)-isoserine (10.0 g) in benzyl alcohol 
(100 ml), warm the mixture to room temperature, and stir for 20 hours. 
Pour the reaction mixture into diethyl ether (300 ml) and filter the 
solid. Wash the solid with diethyl ether and dry in vacuo to give the 
title compound, a tan solid, m.p. 127.degree.-130.degree. C., 
[.alpha.].sub.D.sup.26 =-18.6.degree. (MeOH). 
PREATION 2 
(S)-ISOSERINE ETHYL ESTER, HYDROCHLORIDE 
At 0.degree.-5.degree., add thionyl chloride (2.80 ml) dropwise to 
N-(4-methoxybenzyloxycarbonyl)-(S)-isoserine (5.0 g) in absolute ethanol 
(100 ml). Heat the mixture under reflux for 1 hour and stir for 20 hours 
at room temperature. Concentrate the reaction mixture in vacuo and pour 
the reaction mixture into diethyl ether (300 ml), and filter the solid. 
Wash the solid with diethyl ether and dry in vacuo to give the title 
compound, an amber oil, [.alpha.].sub.D.sup.26 =-19.8.degree. (MeOH). 
In a similar manner, convert N-(4-methoxybenzyloxycarbonyl)-(R)-isoserine 
to (R)-isoserine ethyl ester hydrochloride, a light brown oil, 
[.alpha.].sub.D.sup.26 =+25.0.degree. (MeOH). 
In a similar manner, convert N-(4-methoxybenzyloxycarbonyl)-(R)-isoserine 
to (R)-isoserine methyl ester hydrochloride, a light brown oil, 
[.alpha.].sub.D.sup.26 =+27.2.degree. (MeOH). 
PREATION 2A 
(S)-ISOSERINE ETHYL ESTER. p-TOLUENESULFONATE 
Heat (S)-isoserine (30.0 g) and p-toluenesulfonic acid (57.0 g) in absolute 
ethanol (300 ml) under reflux for 3.5 hours. Concentrate the mixture in 
vacuo. Add absolute ethanol (100 ml) and concentrate the mixture in vacuo 
(twice). Triturate the thick oily residue with diethyl ether and filter to 
obtain the title compound as a white solid, [.alpha.].sub.D.sup.26 
=-13.2.degree. (MeOH). 
PREATION 3 
.alpha.-PHENYL-.beta.-ALANINE ETHYL ESTER 
Method A 
Hydrogenate ethyl phenylcyanoacetate (4.0 g, 21 mmol) in EtOH (75 ml) over 
PtO.sub.2 (2.0 g) at 3 atm. for 3 hr. Concentrate and chromatograph over 
silica, eluting with 2% MeOH/Et.sub.2 O to obtain the title compound as an 
oil. 
Method B 
Step 1: Ethyl .alpha.-hydroxy-.beta.-nitro-.alpha.-phenylpropionate. 
Combine ethyl benzoylformate (7.1 g, 40 mmol), nitromethane (4.9 g, 80 
mmol), and triethylamine (0.8 g, 8 mmol). After 5 days, concentrate and 
distill to obtain the hydroxyester, b.p. 125.degree.-40.degree. C./0.5 mm. 
Step 2: Ethyl .beta.-amino-.alpha.-hydroxy-.alpha.-phenyl-propionate. 
Hydrogenate the above hydroxyester as in Method A to obtain, after 
filtration and concentration, the aminoester as an oil. 
Step 3: Ethyl 5-phenyloxazolidin-2-one-5-carboxylate. Combine the above 
aminoester (1.0 g, 4.1 mmol) with 1,1-carbonyldiimidazole (0.72 g, 4.5 
mmol) and triethylamine (0.40 g, 4.1 mmol) in CH.sub.3 CN (60 ml). After 
18 hr., concentrate and partition between EtOAc and 1N HCl. Dry and 
concentrate the EtOAc to give a solid. Recrystallize from CH.sub.2 
Cl.sub.2 -hexane to obtain the ester as a white solid, m.p. 
114.degree.-7.degree. C. 
Step 4: Ethyl .beta.-amino-.alpha.-phenylpropionate hydrochloride 
(.alpha.-Phenyl-.beta.-alanine ethyl ester, hydrochloride). Hydrogenate 
the above ester (0.73 g, 3.1 mmol) in EtOH (50 ml) for 1 hr. at 3 atm. 
with 20% Pd(OH).sub.2 /C. Filter, concentrate, and treat the residual oil 
with HCl/Et.sub.2 O to obtain the title salt as a white solid, m.p. 
156.degree.-9.degree. C. 
PREATION 4 
.beta.-(2-NAPHTHYL)-.beta.-ALANINE METHYL ESTER, HYDROCHLORIDE 
Mix equimolar amounts of 2-naphthaldehyde and malonic acid in 95% EtOH 
containing two equivalents of ammonium acetate and reflux the reaction 
overnight. Cool the reaction mixture externally with ice water and collect 
the precipitate (.beta.-(2-naphthyl)-.beta.-alanine). Suspend the 
precipitate in dry acidified MeOH and again reflux overnight. Cool and 
collect the title compound, m.p. 188.degree.-190.degree. C. 
PREATION 5 
.beta.-(PHENYL)-ISOSERINE METHYL ESTER, HYDROCHLORIDE 
Mix equimolar amounts of benzaldehyde and methyl chloroacetate and cool to 
0.degree. C. Add a slurry of an equivalent of K-OtBu in dry t-BuOH over 1 
hr. Stir and allow to warm to room temperature overnight. Concentrate in 
vacuo, extract the residue with Et.sub.2 O, and remove the volatiles to 
give a pale oil. Dissolve this oil in cold EtOH and add KOH in EtOH. Cool 
the mixture overnight, collect the precipitate, wash with EtOH, then 
Et.sub.2 O, and dry to obtain the potassium salt of 3-phenyl glycidic 
acid. Dissolve this in conc. NH.sub.4 OH and stir at room temperature for 
a week. Concentrate the solvent, dissolve the residue in dry acidified 
MeOH and reflux overnight, then concentrate and crystallize the residue 
from MeOH/Et.sub.2 O to obtain the title compound, m.p. 
153.degree.-156.degree. C. 
PREATION 5A 
.beta.-(3-THIENYL)-ISOSERINE METHYL ESTER, HYDROCHLORIDE 
In a manner similar to that described in Preparation 5, combine thiophene 
3-carboxaldehyde with ethyl chloroacetate to obtain the title compound. 
PREATION 6 
.beta.-(p-BIPHENYLYL)-.beta.-ALANINE METHYL ESTER HYDROCHLORIDE 
In a manner similar to that described in Preparation 4, suspend equimolar 
amounts of p-biphenyl-carboxaldehyde and malonic acid in 95% EtOH 
containing 2 equivalents of NH.sub.4 OAc and reflux the reaction 36 hrs. 
Cool the reaction mixture externally with ice water and collect the 
precipitate (.beta.-(p-biphenylyl)-.beta.-alanine, m.p. 
222.degree.-224.degree. C.). Suspend in dry acidified MeOH and reflux 
overnight. After cooling, collect the title compound as a precipitate, 
m.p. 208.degree.-210.degree. C. 
PREATION 7 
.beta.-(3-THIENYL)-.beta.-ALANINE METHYL ESTER, HYDROCHLORIDE 
In a manner similar to that described in Preparation 4, suspend equimolar 
amounts of thiophene-3-carboxaldehyde and malonic acid in 95% EtOH 
containing 2 equivalents of NH.sub.4 OAc and reflux the reaction 
overnight. Cool the reaction mixture externally with ice water and collect 
the precipitate (.beta.-(3-thienyl)-.beta.-alanine). Suspend the 
precipitate in dry acidified MeOH and reflux overnight. Cool, concentrate 
and crystallize the residue from Et.sub.2 O to obtain the title compound, 
m.p. 121.degree.-123.degree. C. 
PREATION 8 
.beta.-PHENYL-.beta.-ALANINE METHYL ESTER, HYDROCHLORIDE 
Suspend .beta.-phenyl-.beta.-alanine in dry acidified MeOH and reflux 
overnight. Cool, concentrate and crystallize to obtain the title compound, 
m.p. 142.degree.-144.degree. C. 
PREATION 9 
4-AMINO-2(S)-HYDROXYBUTYRIC ACID ETHYL ESTER, HYDROCHLORIDE 
Add 4-benzyloxycarbonylamino-2(S)-hydroxybutyric acid (2.57 g) to absolute 
ethanol (30 ml) containing thionyl chloride (2.0 ml) and heat the 
resulting mixture under reflux for 20 hours. Cool, filter and concentrate 
the reaction mixture in vacuo to give a pale yellow oil. Chromatograph 
this oil on a column of silica gel (500 ml) using ethyl acetate as eluant 
to obtain a yellow oil, [.alpha.].sub.D.sup.26 =+0.4.degree. (MeOH). 
Hydrogenate the product (1.4 g) in absolute ethanol (50 ml) containing 10% 
Pd/C (0.50 g) at 50 psi for 2 hours. Filter the mixture and concentrate 
the mixture in vacuo to give the title compound as an oil. 
PREATION 10 
(S)-O-METHYL ISOSERINE METHYL ESTER, HYDROCHLORIDE 
Dissolve (S)-isoserine in dry MeOH saturated with HCI and reflux with the 
exclusion of moisture for 24 hours. Cool and remove the volatiles. 
Dissolve the residual waxy solid (mp 90.degree.-95.degree. C.) containing 
(S)-isoserine methyl ester in DMF/methylene chloride, adjust the pH to 
around eight with triethylamine, and react this with a slight molar excess 
of di-t-butyl dicarbonate at room temperature overnight. After this 
period, remove the volatiles and partition the residue between ethyl 
acetate and aqueous citric acid solution. Extract the aqueous layer with 
fresh ethyl acetate and evaporate the combined orgaic layers to give 
N-Boc-(S)-isoserine methyl ester, an oil. Dissolve this in 
dimethoxyethane, add a two-fold molar excess each of iodomethane and 
silver(1) oxide, and reflux in an inert atmosphere. Additional small 
aliquots of Ag.sub.2 O and CH.sub.3 l may be added at eight hour intervals 
as required for a total reaction time of 24 hours. Cool the reaction, 
filter the residue through a Soxhlett thimble and extract with ethyl 
acetate to give N-Boc-O-methyl-(S)-isoserine, methyl ester. Treat this 
with HCl in dioxane/methylene chloride at room temperature for two hours, 
remove the volatiles, and crystallize from methanol/ether to obtain the 
title compound. 
EXAMPLE 1 
N-[2(R,S)-ACETYLTHIOMETHYL-3-PHENYLPROPANOYL]-(S)-ISOSERINE BENZYL ESTER 
Add 2(R,S)-acetylthiomethyl-3-phenylpropionic acid (0.59 g) to 
(S)-isoserine benzyl ester, hydrochloride (0.578 g), 
1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) (0.53 
g), 1-hydroxybenzotriazole (HOBT) (0.37 g) and N-methylmorpholine (0.80 
ml) in dimethylformamide (DMF) (10 ml), and stir the resulting mixture for 
20 hours. Concentrate the reaction mixture in vacuo and partition the 
residue between dichloromethane/water. Concentrate the dried (MgSO.sub.4) 
dichloromethane solution in vacuo. Chromatograph the resulting residue on 
a column of silica gel (1 L) using chloroform:methanol 19.5:1 as eluant to 
give the title compound, a colorless oil, [.alpha.].sub.D.sup.26 
=+12.3.degree. (MeOH). 
In a similar manner, substitute (R)-isoserine methyl ester, hydrochloride 
to obtain N-[2-(R,S)-acetylthiomethyl-3-phenylpropanoyl]-(R)-isoserine 
methyl ester, a colorless oil, [.alpha.].sub.D.sup.26 =-16.0.degree. 
(MeOH). 
EXAMPLE 2 
N-[2(R,S)-MERCAPTOMETHYL-3-PHENYLPROPANOYL]-(S)-ISOSERINE 
Under a nitrogen atmosphere, at 0.degree.-5.degree. C., treat the product 
of Example 1 (0.63 g) in methanol (40 ml) with 1N NaOH (4.70 ml) and then 
keep the reaction mixture at 0.degree.-5.degree. C. for 20 hours. Add 
additional 1N NaOH (1.6 ml) and keep at 0.5.degree. C. for 24 hours. 
Concentrate the mixture under nitrogen, dilute with water, and extract 
with ethyl acetate. Make the basic solution acidic with 1N HCl and extract 
with ethyl acetate. Concentrate the dried (MgSO.sub.4) ethyl acetate in 
vacuo to give the title compound, a colorless viscous oil, 
[.alpha.].sub.D.sup.26 =+6.6.degree. (MeOH). 
In a similar manner substitute 
N-[2(R,S)-acetylthiomethyl3-phenylpropanoyl]-(R)-isoserine methyl ester to 
obtain N-[2(R,S)-mercaptomethyl-3-phenylpropionyl]-(R)-isoserine, a 
colorless viscous oil, [.alpha.].sub.D.sup.26 =-3.3.degree. (MeOH). 
EXAMPLE 3 
N-[2(S)-ACETYLTHIOMETHYL-3-(2-METHYLPHENYL)-PROPANOYL]-(S)-ISOSERINE ETHYL 
ESTER 
Combine 2(S)-acetylthiomethyl-3-(2-methylphenyl)propionic acid (1.65 g) and 
(S)-isoserine ethyl ester hydrochloride (1.10 g), EDC (1.51 g), HOBT (0.99 
g) and N-methylmorpholine (1.50 ml) in DMF (10 ml), and stir the resulting 
mixture for 20 hours. Concentrate the reaction mixture in vacuo and 
partition the residue between dichloromethane/water. Concentrate the dried 
(MgSO.sub.4) dichloromethane solution in vacuo. Chromatograph the 
resulting residue on a column of flash silica gel (300 ml) using ethyl 
acetate:hexane (1:3); ethyl acetate; ethyl acetate:methanol (9:1) as 
eluant to give the title compound, a colorless oil, [.alpha.].sub.D.sup.26 
=0.degree. (MeOH). 
Alternatively, (S)-isoserine ethyl ester, p-toluenesulfonate may be used in 
place of the hydrochloride to prepare the title compound. 
In a similar manner, substitute (R)-isoserine ethyl ester to obtain 
N-[2(S)-acetylthiomethyl-3-(2-methylphenyl)propanoyl]-(R)-isoserine ethyl 
ester, a colorless oil, [.alpha.].sub.D.sup.26 =-25.4.degree. (MeOH). 
EXAMPLE 4 
N-(2-ACETYLTHIOMETHYL-3-PHENYLPROPANOYL)-.beta.-(2-NAPHTHYL)-.beta.-ALANINE 
METHYL ESTER 
Mix equimolar parts of .beta.-(2-naphthyl)-.beta.-alanine methyl ester, 
hydrochloride and 2-acetylthiomethyl-3-phenylpropanoic acid with 1.2 
equivalents each of EDC, triethylamine and HOBT in DMF and stir overnight. 
Evaporate the solvent, partition between EtOAc and water, and concentrate 
the organic layer. Separate on silica using ether/hexane and crystallize 
from acetone/hexane to obtain the title compound, m.p. 
133.degree.-135.degree. C. 
Use a procedure similar to that described in Example 4 to obtain the 
following compounds of formula I wherein n is 1 and p is zero: 
__________________________________________________________________________ 
PROPANOIC 
AMINO ACID ESTER ACID 
Ex 
R.sup.2 
R.sup.4 
t R.sup.3 
Q R.sup.1 
Characterizing Data 
__________________________________________________________________________ 
5 
4-PhC.sub.6 H.sub.4 -- 
H 0 OMe 
Ac 
Ph m.p. 100-104.degree. C.; FAB-MS: 476 (M + 1) 
6 
Ph OH 0 OMe 
Ac 
Ph Isomer A: m.p. 108-110.degree. C. 
Isomer B: m.p. 128-129.degree. C. 
7 
H OH 1 OMe 
Ac 
Ph FAB-MS: 354 (M + 1) 
8 
3-The H 0 OMe 
Ac 
Ph FAB-MS: 406 (M + 1); Elemental 
Analysis: C(59.24) 59.46; 
H(5.72) 5.81; N(3.45) 3.52 
9 
2-The H 0 OEt 
Bz 
Ph FAB-MS: 482 (M + 1) 
10 
Ph OH 0 OMe 
Ac 
o-Tol 
Isomer A: m.p. 140-144.degree. C. 
Isomer B: m.p. 136-137.degree. C. 
11 
H OMe 0 OMe 
Ac 
o-Tol 
m.p. 78-82.degree. C. 
12 
H Benzyl 
0 OEt 
Ac 
o-Tol 
FAB-MS: 442 (M + 1); Elemental 
Analysis: C(68.00) 68.18; 
H(7.07) 6.99; N(3.17) 3.32 
13 
3-The H 0 OMe 
Ac 
o-Tol 
m.p. 75-76.degree. C.; FAB-MS: 420 (M + 1) 
22 
3-The OH 0 OMe 
Ac 
Ph Isomer A: m.p. 117-120.degree. C. 
Isomer B: m.p. 120-122.degree. C. 
__________________________________________________________________________ 
(Ph = phenyl; Bz = benzoyl; oTol = otolyl; The = thienyl) 
EXAMPLE 14 
N-(2-MERCAPTOMETHYL-3-PHENYLPROPANOYL)-.beta.-(2-NAPHTHYL)-.beta.-ALANINE 
and the METHYL ESTER THEREOF 
Hydrolyze the product of Example 4 in aqueous alcoholic K.sub.2 CO.sub.3. 
Evaporate the solvent and treat the residue with zinc and aqueous acid. 
Extract with ethyl acetate and separate by reverse phase chromatography to 
obtain the title compounds, FAB-MS: 394 (M+1) and FAB- MS: 408 (M+1), 
respectively. 
In a manner similar to that described in Example 14, treat the products of 
Examples 5-13 to obtain the corresponding mercaptoacyl-substituted amino 
acids: 
______________________________________ 
Example Starting Material 
Characterizing Data 
______________________________________ 
15 Ex. 5 FAB-MS: 420 (M + 1) 
.sup. 16A 
.sup. Ex. 6A FAB-MS: 360 (M + 1) 
.sup. 16B 
.sup. Ex. 6B FAB-MS: 360 (M + 1) 
17 Ex. 7 FAB-MS: 298 (M + 1) 
18 Ex. 8 FAB-MS: 350 (M + 1) 
19 Ex. 13 m.p. 45-55.degree. C. 
______________________________________ 
EXAMPLE 20 
N-(2-MERCAPTOMETHYL-3-PHENYLPROPANOYL)-.alpha.-PHENYL-.beta.-ALANINE 
Combine the product of Preparation 3 (0.94 g, 4.9 mmol) with triethylamine 
(0.54 g, 5.4 mmol) in 2:1 CH.sub.3 CN/H.sub.2 O (60 ml). Add 
2-(acetylthio)-3-phenylpropionyl chloride (1.37 g, 5.4 mmol). Stir 1 hr., 
add 1N HCl, and extract with Et.sub.2 O. Dry, concentrate, and 
chromatograph the resulting oil on silica, eluting with 4:6 Et.sub.2 
O-hexane, to obtain the amide as a foam. 
Dissolve the above ester in MeOH (6 ml) and add 1.0N NaOH (3.0 ml). Stir 18 
hr., concentrate, add 1.0N HCl (3.0 ml), and extract with EtOAc. Dry and 
concentrate to obtain the title compound, a mixture of diastereomers, as a 
colorless foam, FAB-MS: M+1=344. 
EXAMPLE 21 
N-(2(S)-ACETYLTHIOMETHYL-3-(2-METHYLPHENYL)-PROPANOYL)-.alpha.-PHENYL-.beta 
.-ALANINE ETHYL ESTER 
Combine .alpha.-phenyl-.beta.-alanine ethyl ester, hydrochloride (0.40 g, 
1.7 mmol) with 2(S)-acetylthiomethyl-3-(2-methylphenyl)propionic acid 
(0.44 g, 1.77 mmol), HOBT (0.26 g, 1.7 mmol) and triethylamine (0.25 g, 
2.6 mmol) in 15 ml DMF. Add EDC (0.32 g, 1.7 mmol), stir 18 hr., partion 
with EtOAc-water, and wash with 1N HCl, then NaHCO.sub.3. Chromatograph on 
silica, eluting with 1:1 Et.sub.2 O-hexane, to obtain the title compound, 
a 1:1 mixture of diastereomers, as an oil, [.alpha.].sub.D.sup.26 
=-19.9.degree. (EtOH). 
EXAMPLES 23-25 
In a manner similar to that described in Example 20, treat the products of 
Examples 10, 11 and 21 to obtain the corresponding mercaptoacyl 
substituted amino acids: 
______________________________________ 
Example Starting Material 
Characterizing Data 
______________________________________ 
23 Ex. 10 m.p. 55-60.degree. C. 
24 Ex. 11 m.p. 90-95.degree. C. 
25 Ex. 12 [.alpha.].sub.D.sup.26 = +40.2.degree. (EtOH) 
______________________________________ 
EXAMPLE 26 
4-[2(S)-ACETYLTHIOMETHYL-3-(2-METHYLPHENYL)PROPIONYLAMINO]-2-(S)-HYDROXYBUT 
YRIC ACID ETHYL ESTER 
Using a procedure similar to that described in Example 3, combine 
2(S)-acetylthiomethyl-3-(2-methylphenyl)propionic acid (1.18 g), the 
product of Preparation 9 (0.85 g), EDC (1.09 g), HOBT (0.72 g) and 
N-methylmorpholine (0.52 ml) in DMF (20 ml). Chromatograph the residue on 
silica gel using hexane:ethyl acetate 3:2 as eluant to obtain the title 
compound as a white solid, m.p. 48.degree.-52.degree. C., 
[.alpha.].sub.D.sup.26 =-25.9.degree. (MeOH). 
EXAMPLES 27-29 
In a manner similar to that described in Example 2, hydrolyze the products 
of Examples 3, 22 and 26 to obtain the corresponding mercaptoacyl amino 
acids: 
______________________________________ 
Example Starting Material 
Characterizing Data 
______________________________________ 
27a Ex. 3 - (R)-ester 
[.alpha.].sub.D.sup.26 = +42.4.degree. (MeOH) 
27b Ex. 3 - (S)-ester 
m.p. 99-100.degree. C.; [.alpha.].sub.D.sup.26 = 
+62.6.degree. (MeOH) 
28 Ex. 22 FAB-MS: M + 1 = 366 
29 Ex. 26 [.alpha.].sub.D.sup.26 = +39.7.degree. (MeOH) 
______________________________________ 
The following formulations exemplify some of the dosage forms of the 
compositions of this invention. In each, the term "active compound" 
designates a compound of formula I, preferably 
N-[2(S)-mercaptomethyl-3-(2-methylphenyl)propanoyl]-(S)-isoserine. 
However, this compound may be replaced by equally effective amounts of 
other compounds of formula I. 
Pharmaceutical Dosage Form Examples 
Example A 
______________________________________ 
Tablets 
No. Ingredient mg/tablet mg/tablet 
______________________________________ 
1 Active Compound 100 500 
2 Lactose USP 122 113 
3 Corn Starch, Food Grade, as a 
30 40 
10% Paste in Purified Water 
4 Corn Starch, Food Grade 
45 40 
5 Magnesium Stearate 3 7 
Total 300 700 
______________________________________ 
Method of Manufacture 
Mix Items Nos. 1 and 2 in suitable mixer for 10-15 minutes. Granulate the 
mixture with Item No. 3. Mill the damp granules through a coarse screen 
(e.g., 1/4", 0.63 cm) if necessary. Dry the damp granules. Screen the 
dried granules if necessary and mix with Item No. 4 and mix for 10-15 
minutes. Add Item No. 5 and mix for 1-3 minutes. Compress the mixture to 
appropriate size and weigh on a suitable tablet machine. 
Example B 
______________________________________ 
Capsules 
No. Ingredient mg/capsule 
mg/capsule 
______________________________________ 
1 Active Compound 100 500 
2 Lactose USP 106 123 
3 Corn Starch, Food Grade 
40 70 
4 Magnesium Stearate NF 
4 7 
Total 250 700 
______________________________________ 
Method of Manufacture 
Mix Item Nos. 1, 2 and 3 in a suitable blender for 10-15 minutes. Add Item 
No. 4 and mix for 1-3 minutes. Fill the mixture into suitable two-piece 
hard gelatin capsules on a suitable encapsulating machine. 
Example C 
______________________________________ 
Parenteral Preparation 
Ingredient mg/vial mg/vial 
______________________________________ 
Active Compound Sterile Powder 
100 500 
______________________________________ 
For reconstitution add sterile water for injection or bacteriostatic water 
for injection.