2-Chloro-6-fluorobenzaldehyde was converted to 4-(1-piperazinyl)benzo[b]thiophene dihydrochloride (18), an intermediate in the synthesis of brexpiprazole, via a five-step sequence in 54% overall yield. This procedure requires no expensive catalyst and avoids the side products produced in the coupling step in the reported process. Several kilograms of compound 18 were prepared using this economical and scalable process.

中文翻译：

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改进的4-（1-哌嗪基）苯并[ b ]噻吩二盐酸盐的合成

通过五步序列将2-氯-6-氟苯甲醛转化为4-（1-哌嗪基）苯并[ b ]噻吩二盐酸盐（18），其总收率为54％。该方法不需要昂贵的催化剂，并且避免了所报道的方法在偶联步骤中产生的副产物。使用该经济且可扩展的方法制备了几千克的化合物18。