Abstract: There are presented novel quinazoline derivatives, namely 2-(4-substituted-carbamoyl-piperazin-1-yl)quinazoline derivatives, 2-(4-substituted-carbamoyl-homopiperazin-1-yl)quinazoline derivatives, 2-(4-substituted-thiocarbamoyl-piperazin-1-yl)quinazoline derivatives and 2-(4-substituted-thiocarbamoyl-piperazin-1-yl)quinazoline derivatives, having excellent antihypertensive activities.

Abstract: Novel quinazoline compounds and antihypertensive compositions containing said compounds are disclosed; said compounds having the formula: ##STR1## wherein R.sup.1 is a hydrogen atom or an alkyl group having 1-5 carbon atoms;R.sup.2 is a group of the formula ##STR2## in which Y is a hydrogen atom, an alkyl group of 1-5 carbon atoms, an alkoxy group of 1-5 carbon atoms, an alkenyloxy group, a methylenedioxy group, a nitro group, a halogen atom, a trifluoromethyl group, an acyloxy group, a hydroxy group, an unsubstituted or substituted amino group or a condensed benzene nucleus and m is an integer of 1-3 inclusive, or a group of the formula ##STR3## in which X is an oxygen atom, a sulfur atom or a carbon-nitrogen double bond and Z is a hydrogen atom, an alkyl group of 1-5 carbon atoms, an alkoxy group of 1-5 carbon atoms, a nitro group or a halogen atom; and n is an integer of 2-3 inclusive;provided that, when R.sup.2 is the said group ##STR4## n is 2 and R.sup.1 is a hydrogen atom or, when R.sup.