4-AMINO-2-(3-OR 4-SUBSTITUTED PIPERIDINO)-QUINAZOLINES AND PHARMACEUTICAL COMPOSITIONS

Regulators of the cardiovascular system and, in particular, in the treatment of hypertension having the formula wherein R is lower alkyl; X, is a 3- or 4-position substituent and is -(CH2)nCONR1R2, -O(CH2)nCONR1R2 or wherein n is 0, 1 or 2; R1 is hydrogen or lower alkyl, and R2 is lower alkyl; lower alkenyl, lower alkynyl, phenyl, substituted phenyl, C3-C7 cycloalkyl; lower alkyl substituted by phenyl, substituted phenyl, C3-C7 cycloalkyl, halogen, trifluoromethyl, hydroxy, lower alkoxy, lower alkoxycarbonyl, phenoxy, substituted phenoxy or -NR3R4 wherein R3 and R4 each represent hydrogen, lower alkyl, lower alkanoyl or lower alkylsulfonyl; with the proviso that any O, N or halogen atom in R2 is separated by at least 2 carbon atoms from the nitrogen atom to which R2 is attached; or R1 and R2 taken together with the nitrogen atom to which they are attached form a morpholino group optionally substituted by one or two lower alkyl groups, or a 1,2,3,4-tetrahydroisoquinolyl group optionally substituted on the benzene ring portion by one or two lower alkoxy groups; the pharmaceutically acceptable bioprecursors therefor, and the pharmaceutically acceptable acid addition salts thereof.