Quinazolinone derivatives and a process for production thereof

Abstract

3,4-Dihydro-2(1H)-quinazolinone derivatives of the formula, ##STR1## wherein R.sub.1 and R.sub.2 signify individually a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group, a trifluoromethyl group, a lower alkylthio group, a lower alkylsulfonyl group or a halogen atom; R.sub.3 signifies a phenyl group, a halophenyl group, a lower alkylphenyl group, a lower alkoxyphenyl group, a trifluoromethylphenyl group, a lower cycloalkyl group, a lower cycloalkenyl group, a pyridyl group, a pyrrolyl group, a furyl group, a thienyl group or a naphthyl group; R.sub.4 signifies a lower alkyl group, a lower alkenyl group, an aralkyl group, a lower cycloalkylalkyl group, a lower cycloalkyl group, a lower alkoxyalkyl group, a lower alkylthioalkyl group, a lower hydroxyalkyl group, a lower alkanoyloxyalkyl group, a phenyl group, a halophenyl group, a trifluoromethylphenyl group, a lower alkylphenyl group a lower alkoxyphenyl group, a pyridyl group or a group of the formula ##STR2## wherein n signifies an integer of 1 to 4; and R.sub.5 and R.sub.6 signify individually a lower alkyl group, provided that they may form together with the adjacent nitorgen atom an optionally substituted 5- or 6-membered heterocyclic ring, which may further contain a hetero atom); and R signifies a hydrogen atom, a lower alkyl group, a lower alkenyl group, a lower alkoxyalkyl group, a lower alkylthioalkyl group, an aralkyl group, a lower cycloalkylalkyl group, a lower trihalomethylalkyl group or a group of the formula ##STR3## (wherein n, R.sub.5 and R.sub.6 signify the same as defined above), which have excellent pharmacological properties such as central nervous system depressant, anti-inflammatory, analgestic and anti-microbial activities, can be produced by reducing a compound of the formula, ##STR4## wherein R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 have the same meanings as defined above; and X.sub.1, X.sub.2 and X.sub.3 signify individually a halogen atom, or by the substitution reaction of the ring nitrogen atom of a 1 or 3-unsubstituted 3,4-dihydro-2(1H)-quinazolinone derivative.