6-溴甲基-3,4-二氢-2-甲基-4-氧代喹唑啉的合成

用对甲基苯胺与水合三氯乙醛、盐酸羟胺反应制得对甲基(N-肟基乙酰)苯胺，再与浓硫酸反应生成5-甲基靛红，后经碱性过氧化氢氧化，制得2-氨基-5-甲基苯甲酸。将2-氨基-5-甲基苯甲酸与硫代乙酰胺反应生成的3，4-二氢-2，6_二甲基4氧代喹唑啉，经N-溴代琥珀酰亚胺溴化得到标题化合物，其结构经IR，MS，^1HNMR和元素分析确证，5步反应总收率为23．1％。

Synthesis of 6-bromomethyl-3,4-dihydro-2-methyl-4-oxoquinazoline

Bromomethyl-3,4-dihydro-2-methyl-4-oxoquinazoline is the key intermediate for the synthesis of some anti-cancer drugs inhibiting thymidylate synthase.In this paper,2-amino-5-methylbenzoic acid was prepared through reacting p-toluidine with chloral hydrate and hydroxylamine hydrochloride,treated with concentrated sulfuric acid,followed by alkaline H 2O 2 oxidation of the resulted 5-methylisatin.Then,heating 2-amino-5-methylbenzoic acid with thioacetamide yielded 3,4-dihydro-2,6-dimethyl-4-oxoquinazoline which was brominated with N-bromosuccinimide in the presence of benzoyl peroxide to give the title compound in 23.1% overall yield.IR, 1HNMR ,MS and elemental analysis of two intermediates and the final product are consistent with their structures.