Abstract: A biphenyl derivative represented by the following general formula (1) and a pharmaceutically acceptable salt thereof: [In the formula (1), A represents a single bond, —CH2—, —CO—, —CS— or —SO2—; B represents a single bond or —CH2—; R1 represents a hydrogen atom, —OH, —NR11R12 (wherein R11 and R12 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), —OCOCH3, or a halogen atom; R2 represents a hydrogen atom or R1 and R2 form a group ═O together; R3 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; provided that in the formula, the absolute configuration of the position a may be either R or S]. The compound of the present invention has considerably high safety and efficacy and is useful as, in particular, a vasopressin receptor antagonist.

Abstract: The tetrazolylphenyl pivalate of the the following general formula or a pharmaceutically acceptable salt thereof: ##STR1## wherein R.sup.1 and R.sup.2 each represents a hydrogen atom, a lower alkyl group or other substituents; an elastase-inhibitory composition, a composition for preventing and treating emphysema and a composition for preventing and treating endotoxin-induced lung disorders each comprising the foregoing tetrazolylphenyl pivalate derivative or a non-toxic or acid-addition salt thereof.

Abstract: A 1,2,4-oxadiazole derivative is represented by the following general formula (I): ##STR1## wherein R.sup.1 represents a lower alkyl or cycloalkyl group, a lower alkyl group substituted with a halogen atom, a lower alkylamino group or a phenyl group; R.sup.2 represents a hydrogen atom, a lower dialkylamino group, a cyclic alkylamino group, a cyclic amino group having an oxygen or nitrogen atom in the ring, a phenyl group which may be substituted with a halogen atom, a pyridyl group, an imidazolyl group, an alkylimidazolyl group, a benzimidazolyl group or a 2-oxopyrrolidinyl group; and n is 1, 2 or 3. The derivative has excellent monoamine oxidase-inhibitory activity and is effective as a medicine for treating Parkinson's disease.

Abstract: New 1,3,4-thiadiazole derivatives of the general formula (I): ##STR1## wherein R.sub.1 represents a group of the formula: ##STR2## and R.sub.2 represents an amino, lower alkylamino, cyclohexylamino, benzoylamino, mercapto or lower alkylthio group, a process for the production of them and the use of the derivatives as antiulcer agents.