4-Methylenepiperidine hydrochloride 1 is a key intermediate for synthesis of the novel antifungal drug efinaconazole 2. In this work, a simple and robust process has been developed to synthesize 4-methylenepiperidine hydrochloride 1, with a high overall yield of 99.1% at a high purity of 99.7% in a large-scale. Moreover, this synthetic process avoided the uses of organolithium reagent and column chromatography process which are not desirable for industrial production.

中文翻译：

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大规模合成4-亚甲基哌啶盐酸盐的简单而稳定的方法

4-亚甲基哌啶盐酸盐1是合成新型抗真菌药物efinaconazole 2的关键中间体。在这项工作中，开发了一种简单而可靠的方法来合成4-亚甲基哌啶盐酸盐1，在高效率下的总收率为99.1％。大规模纯度为99.7％。而且，该合成方法避免了使用有机锂试剂和柱色谱法，这对于工业生产是不希望的。