Abstract: A cyclic iminocarboxylic acid derivative of the formula: ##STR1## or a salt thereof, wherein X.sup.1 and X.sup.2 are each hydrogen, halogen, lower alkoxy, lower alkyl, trifluoromethyl, nitro, amino, alkylamino, aralkylamino, acetylamino or ethoxycarbonylamino, Y is --CO-- or --SO.sub.2 --, Z is --CH.sub.2 -- or --S--, and R is hydrogen or lower alkyl. Such compounds are useful as antihypertensive agents.

Abstract: Imidazolido[1,5-c]thiazolidine-3-spiro-4'-piperidine compounds of the formula: ##SPC1##Wherein R.sup.1 represents a member selected from the group consisting of a hydrogen atom, an alkyl group of from 1 to 4 carbon atoms, a benzyl group, a p-chlorobenzyl group, a 4,5-dimethoxybenzyl group, a 4,5,6-trimethoxybenzyl group, a phenethyl group, an acetyl group, a benzoyl group, a trimethoxybenzoyl group, a methoxycarbonyl group, an ethoxycarbonyl group, a 4,4-bis(p-fluorophenyl)butyl group and a group of the formula ##SPC2##(in which Y represents a member selected from the group consisting of H, F and CH.sub.3 O, and n represents an integer of 1, 2 or 3); R.sup.