Abstract: Compounds of the formula ##STR1## wherein R.sup.1 is a straight or branched chain alkynyl group containing from 3 to 9 carbon atoms, inclusive, and nontoxic pharmaceutically acceptable acid addition salts thereof, are potent anti-ulcer agents.

Abstract: A one-step process for the preparation of 2,4-dihaloquinazolines is disclosed beginning with methoxycarbonyl- or phenoxycarbonyl-derivatives of substituted phenylureas which are cyclized and concomitantly halogenated with a cyclizing-halogenating reagent such as N,N-dimethylaniline in phosphorus oxychloride. The 2,4-dihaloquinazolines of the instant process are particularly valuable as intermediates in the preparation of 4-amino-2-(4-substituted-piperazin-1-yl) quinazolines useful in the treatment of cardiovascular disorders such as hypertension.

Abstract: 2-Halo-4-aminoquinazolines are produced by a two-step process involving cyclization of 1-phenyl-3-cyanoureas or 1-phenyl-3-cyanothioureas in the presence of phosphorus halides and phosphorus oxyhalides to provide a phosphoquinazoline intermediate which is hydrolyzed to the quinazoline. Exemplary of the process is the intramolecular cyclization of 1-(3,4-dimethoxyphenyl)-3-cyanourea in the presence of phosphorus pentachloride and phosphorus oxychloride to a phosphoquinazoline intermediate which is subsequently hydrolyzed with formic acid to 2-chloro-4-amino-6,7-dimethoxy-quinazoline. The 2-halo-4-aminoquinazolines of the instant process are particularly valuable as intermediates in the preparation of 4-amino-2-(4-substituted-piperazin-l-yl)quinazolines useful in the treatment of cardiovascular disease, e.g. hypertension.

Abstract: Compounds of the formula ##SPC1##Where A is selected from the group consisting of hydrogen, halogen, lower alkoxy, lower alkylthio, hydroxyl, thio, trifluoromethyl, lower diakylaminoalkyl, amino, lower alkylamino and lower dialkylamino,Where B is selected from the group consisting of hydrogen, lower alkyl, lower alkoxyl, lower alkylthio, hydroxyl, thio, trifluoromethyl, lower dialkylaminoalkoxyl, amino, lower alkylamino, and lower dialkylamino,Where C is selected from the group consisting of hydrogen, halogen, lower alkyl, lower alkoxyl, lower alkylthio, hydroxyl, thio, trifluoromethyl, lower dialkylaminoalkoxy, amino, lower alkylamino and lower dialkylamino,Where D is selected from the group consisting of hydrogen, halogen, lower alkyl, lower alkoxy, lower alkylthio, hydroxyl, thio, trifluoromethyl, lower dialkylaminoalkoxyl, amino, lower alkylamino and lower diaklamino,Where n is an integer from 2 to 12 inclusive,And Y is selected from the group consisting of amino, lower alkylamino, lower dialkylamino, and

Abstract: Compounds having the formula ##STR1## wherein Z is a substituted or unsubstituted oxazole, is isoxazole, thiazole or isothiazole group are potent antihypertensive drugs which have generally less .alpha.-adrenergic blocking activity than does 2-[4-(2-furoyl)-piperazin-1-yl]-4-amino-6,7-dimethoxy-quinazoline which is a known potent antihypertensive drug.

Abstract: The 4-amino-6,7-dimethoxy-2-[4-(5-lower alkylthio-1,3,4-oxadiazole-2-carbonyl)-piperazin-1-yl]-quinazolines are potent antihypertensive drugs which have little or no .alpha.-adrenergic blocking activity.