Abstract: The present invention relates to novel pyrimidine derivatives of the formulae (I-1) and (I-2) and pharmaceutically acceptable salts thereof which possess an excellent anti-secretory activity, pharmaceutical compositions containing same as an active ingredient, their novel intermediates, and processes for the preparation thereof: ##STR1## wherein: R.sub.4 and R.sub.5, which may be the same or different, are independently hydrogen or a C.sub.1 -C.sub.3 alkyl group, or jointly form a cyclopentyl or cyclohexyl ring;A is a group of formula(II): ##STR2## wherein R.sub.1 and R.sub.2 are, independently of each other, hydrogen or a C.sub.1 -C.sub.3 alkyl group, and R.sub.3 is hydrogen, a C.sub.1 -C.sub.3 alkyl group or a halogen; andB is 1-(substituted)-1,2,3,4-tetrahydroisoquinolin-2-yl of formula (III-1) or 7-(substituted)-4,5,6,7-tetrahydrothieno?2,3-c!pyridin-6-yl of formula (III-2) ##STR3## wherein R.sub.6 is hydrogen or a C.sub.1 -C.sub.3 alkyl group.

Abstract: A quinazoline derivative represented by formula(I) or a pharmaceutically acceptable salt thereof is useful for the treatment of peptic ulcer, wherein: ##STR1## R.sub.1 and R.sub.2 are each hydrogen or a C.sub.1 -C.sub.4 alkyl group; R.sub.3 is hydrogen or a halogen;R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8 and R.sub.9, which may be the same or different, are each hydrogen, a C.sub.1 -C.sub.4 alkyl group, a cyclopropyl group, or a C.sub.1 -C.sub.4 alkyl group substituted with a halogen; andR.sub.10 is a methoxy group.