Abstract

By means of the Hurd–Mori reaction, 2-(1,2,3-thiadiazol-4-yl)-5-methyl-thiophene was synthesized. Its bromination with N-bromosuccinimide under conditions of radical initiation leads to a labile 2-bromomethyl derivative which, in the presence of proton donors or when heated, rearranges to 2-(1,2,3-thiadiazol-4-yl)-4-bromo-5-methylthiophene. The possibility of rearrangement was confirmed by quantum chemical calculations. Chlorination of 2-(1,2,3-thiadiazol-4-yl)-5-methylthiophene with sulfuryl chloride both in the presence of AIBN and without it leads to 2-(1,2,3-thiadiazol-4-yl)-3,4-dichloro-5-methylthiophene. Intermediate products that form in the course of both processes are established and schemes of their formation are offered. Bromination of 2-(1,2,3-thiadiazol-4-yl)-4-bromo- and -3,4-dichloro-5-methylthiophenes with N-bromosuccinimide proceeds at the methyl group. Obtained bromomethyl derivatives undergo nucleophilic substitution reactions in the usual manner.

中文翻译：

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2-(1,2,3-噻二唑-4-基)-5-甲基噻吩的合成与卤化

摘要

通过Hurd-Mori反应，合成了2-(1,2,3-噻二唑-4-基)-5-甲基噻吩。它在自由基引发条件下与 N-溴代琥珀酰亚胺发生溴化，生成不稳定的 2-溴甲基衍生物，在质子供体存在下或加热时，该衍生物重排为 2-(1,2,3-噻二唑-4-基)-4 -溴-5-甲基噻吩。量子化学计算证实了重排的可能性。在 AIBN 存在和不存在的情况下，2-(1,2,3-噻二唑-4-基)-5-甲基噻吩与磺酰氯的氯化反应都会生成 2-(1,2,3-噻二唑-4-基) -3,4-二氯-5-甲基噻吩。建立了在这两个过程中形成的中间产物并提供了它们的形成方案。2-(1,2,3-噻二唑-4-基)-4-溴-和-3,4-二氯-5-甲基噻吩与N-溴琥珀酰亚胺在甲基处进行溴化。所得的溴甲基衍生物按常规方式进行亲核取代反应。