PROCESS FOR PREPARING QUINAZOLIN-4-ONE DERIVATIVE

摘要

The present invention provides a novel process for preparing a series of quinazolin-4-one derivatives in high yields with reduced amounts of byproducts, the process comprising reacting, in the presence of a base, a trialkylsilyl halide with a compound represented by the formula (see formula I) wherein R1, R2, R3 and R4 are the same or different and each represent a hydrogen atom, a lower alkyl group, a halogen atom, a nitro group, a lower alkoxy group, a cyano group, an N-lower alkylcarbamoyl group, a lower alkoxycarbonyl group, a lower alkanoyloxy group or a halogen-substituted lower alkyl group; R5 is a phenyl group which may have 1 to 3 substituents each selected from a lower alkyl group, a lower alkoxy group or a halogen atom, a lower alkyl group, a phenyl-lower alkyl group which may have a halogen atom as a substituent on the phenyl ring, a lower alkenyl group, a lower alkoxy- lower alkyl group or a lower alkynyl group; R6 is a lower alkyl group, a halogen-substituted lower alkyl group, a lower alkoxycarbonyl group or a phenyl group which may have, as a substituent, a lower alkyl group or a group of the formula (see formula II) wherein A is an oxygen atom or a single bond, Z is a lower alkylene group, R7 is a lower alkyl group and R8 is a lower alkoxy group, a phenyl group or a phenyl-lower alkoxy group which may have a halogen atom on the phenyl ring; to produce the quinazolin-4-one derivatives which is valuable as pharmaceuticals or intermediates for synthesis thereof and represented by the formula (see formula III) wherein R1, R2, R3, R4, R5 and R6 are as defined above.