QUINAZOLINE DERIVATIVE, PRODUCTION THEREOF AND ANTI-ULCER AGENT CONTAINING SAME COMPOUND AS ACTIVE INGREDIENT

NEW MATERIAL:A compound expressed by formula I or acid-added salt of said compound (R is H or lower alkyl). EXAMPLE:2-(1-piperazinyl)-4-phenylthioquinazoline. USE:Used as an anti-ulcer agent. Said compound has a strong enhancing action to protecting factor together with a strong suppressing action to attacking factor. PREPARATION:A compound expressed by formula II is reacted with a compound expressed by formula III without solvent, in an inert organic solvent such as ethanol or in a mixed solvent such as toluene-water in the presence of a phase- transfer catalyst (e.g. tetrabromo-n-butylammonium) and a base (e.g., NaOH) to afford the compound expressed by formula I. The compound expressed by formula II is a new compound and is obtained by reacting, e.g. 2,4- dichloroquinazoline and thiophenol.