1,2-Benzisothiazoles. Part IV. Preparation of the 3-methyl derivative from o-mercaptoacetophenone oxime: a re-examination
作者:K. Clarke、C. G. Hughes、R. M. Scrowston
DOI:10.1039/p19730000356
日期:——
substituted benzothiazole in each case. Italian workers had reported previously that the cyclisation of o-mercaptoacetophenone oxime and related compounds gave entirely the 3-methyl-1,2-benzisothiazole derivative. It seems probable that their starting material, which they believed to be o-mercaptoacetophenone oxime, was 2-imino-5-methyl-3,1,4-benzoxathiazepine (14). This compound is decomposed to 3-methyl-1
用多磷酸处理邻巯基苯乙酮肟,可得到2-甲基苯并噻唑和3-甲基-1,2-苯并噻唑的混合物,其中2-甲基苯并噻唑是由肟在环化之前进行贝克曼重排而得到的。前一种产品始终占主导地位,但比例取决于环化温度。在每种情况下,对4'-氯-,5'-氯-和5'-硝基-2'-巯基苯乙酮肟进行类似的处理,主要得到取代的苯并噻唑。意大利工人以前曾报道过,邻巯基苯乙酮肟和相关化合物的环化反应完全产生了3-甲基-1,2-苯并噻唑衍生物。似乎有可能,他们的原料,他们认为是Ø-巯基苯乙酮肟是2-亚氨基-5-甲基-3,1,4-苯并恶噻嗪(14)。通过在多磷酸中或在合适的惰性溶剂中加热,将该化合物分解为3-甲基-1,2-苯并噻唑和氰酸。