Abstract: A process for producing 1-substituted tetrahydroquinazolines represented by the formula (III): ##STR1## wherein Z represents a methylene group which is optionally substituted by an alkyl group; R.sub.6 represents an alkyl group or an aralkyl group; R.sub.1 and R.sub.2 independently represent a hydrogen atom, a halogen atom, a nitro group, an azido group, an alkyl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxygroup, or an amino group represented by XNR.sub.4 R.sub.5 in which X represents a direct bond, an alkylene group or a carbonyl group, and N, R.sub.4 and R.sub.5 may form together a five- or six-membered heterocyclic ring or R.sub.4 and R.sub.5 independently represent an alkyl group or an acyloxy alkyl group; and R.sub.