Substituted acylpiperazinoquinazolines and pharmaceutical compositions containing same

Substituted acylpiperazinoquinazolines of formula I wherein n is 0 or 1, R represents an alkyl group with 1 to 4 carbon atoms or a benzyl group, and R1 is a hydrogen atom, a methyl group or a phenyl group. Addition salts of these compounds with inorganic and organic acids are also disclosed. The compounds possess a significant antihypertensive activity. They can be prepared by the reaction of 2-halogeno quinazoline derivatives with the corresponding acylpiperazines, followed (if required) by neutralization of the respective base with a suitable acid to form its pharmaceutically convenient addition salt. The acid addition salts, especially hydrochlorides, are readily soluble in water and give stable, almost neutral aqueous solutions which can be used in parenteral (injectable) and peroral medicinal dosage forms.