New quinazoline derivatives are disclosed, as represented by the following formula: ##STR1## wherein A is hydrogen atom or lower alkyloxy group; R.sub.4 is hydrogen atom, a lower alkyl, lower alkyloxy or a halogen atom group. Y is hydrogen atom, lower alkyloxy, sulfamoyl or Y and R.sub.4, taken together, are joined to form --O--CH.sub.2 --CH.sub.2 --O--; Z is a 4-oxopiperidino, 4-thioxopiperidino, 4-oximepiperidino, 4-O-loweralkyl-oxime-piperidino, 4-O-(3-lower alkyl-2-hydroxypropyl)-oxime-piperidino, 4-O-(3-lower alkylamino-2-hydroxypropyl)-oxime-piperidino or 4-O-(3-N'-lower alkyl, N'-benzylamino-2-hydroxypropyl)-oxime-piperidino group. These compounds are useful as anti-hypertensive agents.