Abstract: Imidazole-containing peptide of the formula: ##STR1## wherein R.sup.1 is a branched alkyl group, a branched alkyloxy group or an aryl-substituted lower alkyloxy group, R.sup.2 and R.sup.4 are the same or different and each is hydrogen atom or a lower alkyl group, R.sup.3 and R.sup.5 are a phenyl-substituted lower alkyl group, R.sup.6 is hydrogen atom or a lower alkoxycarbonyl group, R.sup.7 is hydrogen atom or a nitrogen-containing heterocyclic group-substituted lower alkylthio group, X.sup.1 and X.sup.2 are the same or different and each is ##STR2## A is a lower alkylene group which may be substituted with a substituent selected from the group consisting of a lower alkoxy group, hydroxymethyl group and a group of the formula: ##STR3## and R.sup.8 and R.sup.

Abstract: Disclosed are a process for preparing an optically active 2-oxoimidazolidine derivative of the formula: ##STR1## wherein R.sup.1 represents hydrogen atom or a lower alkyl group, according to the process described in the specification; and a 3-acyl-2-oxoimidazolidine-4-carboxylin acid ester derivative having (S, R) configuration of the formula: ##STR2## wherein R.sup.2 represents a tert-butyl group or a benzyl group, and R.sup.3 represents a lower alkyl group or an aryl group.

Abstract: A thiophene derivative of the formula: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are a lower alkyl group, Ring A is a substituted or unsubstituted phenyl group and p is an integer of 1 to 3, or a salt thereof and processes for preparing the same are disclosed. The thiophene derivative (I) is useful as the regulator of gastrointestinal tract motility.

Abstract: A thiophen derivative of the formula: ##STR1## wherein R.sup.1, and R.sup.2 and R.sup.3 are a lower alkyl group, Ring A is phenyl, a lower alkylenedioxy-substituted phenyl, a phenyl group having 1 to 3 substituent(s) selected from the group consisting of a lower alkyl group, a lower alkylthio group, a lower alkoxy group, a phenyl-lower alkoxy group, a lower alkoxycarbonyl group, a halogen atom, amino group and hydroxy group, X is --OCO--, --O-- or --S--, m and n are an integer of zero or 1, and p and q are an integer of zero, 1 or 2, or a salt thereof.

Abstract: Novel 2-oxo-imidazolidine derivative of the formula: ##STR1## wherein R.sup.1 is lower alkyl or phenyl-lower alkyl, R.sup.2 is lower alkyl, R.sup.3 is alkyl of one to 12 carbon atoms or phenyl-lower alkyl and R.sup.4 is hydrogen or lower alkyl, and a pharmaceutically acceptable salts thereof are disclsoed. Said compounds (I) and salts thereof are useful as hypotensive agents.

Abstract: A compound of the formula: ##STR1## wherein R.sup.1 is hydrogen or methyl, is prepared by condensing a compound of the formula: ##STR2## wherein R.sup.2 is alkyl, aryl or aralkyl and R.sup.1 is same as above, or a reactive derivative thereof with 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid or an ester thereof to give a compound of the formula: ##STR3## wherein R.sup.3 is an ester residue and R.sup.1 and R.sup.2 are same as above, followed by hydrolysis or ammonolysis of said compound (IV). The compound (I) is useful as a diagnostic or therapeutic agent for angiotensin-related hypertension.

Abstract: A compound of the formula: ##STR1## wherein R is methyl or 2-methylthioethyl, is prepared by either (A) condensing a compound of the formula: ##STR2## wherein R is the same as above, or a reactive derivative thereof with 3,4-diethoxycarboxyphenethylamine, or (B) condensing the compound (II) or a reactive derivative thereof with dopamine, followed by reacting the resultant product with an ethoxycarbonyl halide. The compound (I) shows potent renal blood flow-increasing activity and is useful for the treatment of renal hypertension, congestive heart failure and other diseases due to renal blood flow disturbances.