Abstract: The invention relates to a new process for preparing active esters or carboxylic acids, which consists in reacting a carboxylic acid, in the presence of an agent for binding hydrohalic acid, with a carbonate of formula: ##STR1## in which R.sup.1 denotes either a radical of formula ##STR2## in which R.sup.3 and R.sup.4, which may be identical or different, are not hydrogen atoms and denote organic radicals which may be substituted or unsubstituted and saturated or unsaturated, and may be or may not be bound to a polymer, and which can be joined together to form a hetero-cyclic system with the nitrogen atom,or a substituted or unsubstituted aryl radical which may or may not be bound to a polymer,R.sup.2 denotes a hydrogen atom, an aliphatic or cycloaliphatic radical which may be substituted or unsubstituted and saturated or unsaturated, or a substituted or unsubstituted aromatic radical,and X denotes a halogen atom.This process is especially useful for the synthesis of active esters of N-protected amino acids.

Abstract: The invention relates to the peptides of the formula: ##STR1## in which: R.sub.1 represents hydrogen or a protecting group for the amine group, such as t-butoxycarbonyl, benzyloxycarbonyl or lower alkanoyl groups;X represents beta-alanine glycine or a direct bond between R.sub.1 and the amine group; andR.sub.2 represents a group chosen from: ##STR2## corresponding to the side chains of the natural amino acid leucine, methionine and norleucine.These peptides inhibit gastric secretion.

Abstract: The invention relates to the peptides of the formula: ##STR1## in which: R represents hydrogen or a protecting group for the terminal amine group, such as t-butoxycarbonyl (Boc), benzyloxycarbonyl (Z) or lower alkanoyl;X.sub.1 represents either beta-Ala or a direct bond between R and the terminal amine group of the amino acid TRP;TRP denotes either the L isomer or the D isomer of tryptophan;X.sub.2 represents L-leucine, L-methionine or L-norleucine; andY denotes hydrogen, a halogen atom (preferably fluorine or chlorine), a trifluoromethyl group, a cyano group or a nitro group.These peptides inhibit gastric secretion.

Abstract: The invention relates to peptides of general formula:R--A--Gly--Trp--B--Asp--NH.sub.2 (I)in which:Asp NH.sub.2 represents the amide in .alpha. position of the aspartic acid of formula: ##STR1## R represents hydrogen, a protector group of the terminal amine function such as t.butyloxy carbonyl (BOC), benzyloxy carbonyl (Z), lower alkanoyl,A designates:either tyrosine, tyrosine-O-sulfate, threonine or methionine;or a dipeptide selected from: --Ala--TYR--, --TYR--Thr--, --TYR Met--, TYR designating either of the 2 amino-acids tyrosine or tyrosine-O-sulfate;or a tripeptide selected from: --Glu--Ala--TYR--, Asp--TYR--Thr--, --Asp--TYR--MET--;or a tetrapeptide selected from: --Glu--Glu--Ala--TYR--, --Gln Asp--TYR--Thr--, --Arg--ASP--TYR--Met--;or a pentapeptide selected from: --Glu--Glu--Glu--Ala--TYR--, --Pyr--Gln--Asp--TYR--Thr--, --Asp--Arg--Asp--TYR--Met;B designates methionine, leucine or norleucine.

Abstract: Heterocyclic compounds of the general formula: ##STR1## wherein: R.sub.1 represents alkyl, haloalkyl, alkenyl, haloalkenyl, arylalkyl, arylhaloalkyl, cycloalkyl, halocycloalkyl, aryl, haloaryl, alkoxyalkyl or haloalkoxyalkyl;X.sub.1 is chlorine, bromine, or fluorine;X.sub.2 and X.sub.3 are hydrogen, chlorine, bromine or fluorine;A represents oxygen or sulphur, S-O ##STR2## or N-R.sub.8 ; R.sub.8 is hydrogen, alkyl, haloalkyl, hydroxyalkyl, alkoxyalkyl, arylalkyl, aryl or ##STR3## B represents ##STR4## m is 0, 1 or 2; n and p are 0 or 1;R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R'.sub.2, R'.sub.3, R'.sub.4, R'.sub.5 are the same or different and are hydrogen, alkyl, alkoxyalkyl, haloalkyl, or hydroxyalkyl;and Y and Z are the same or different and are hydrogen, halogen, alkyl or alkoxy.These compounds are used as antidotes against herbicides.

Abstract: The novel derivatives of pepstatin have the general formula (I) below in which X, Y and Z, are identical or different, and each represent an amino-acid selected from arginine, glutamic acid, aspartic acid, lysine, histidine and valine, the carboxyl function of the terminal amino-acid being esterifiable. The indices a, b and c are each equal to zero or 1, the sum a+b+c being equal to 1, 2 or 3. The invention also includes the water soluble salts and their preparation, and the compositions containing them. ##STR1## These novel products are particularly useful in the diagnosis and treatment of arterial hypertension due to the action of renine.