Intramolecular cyclization of alkylhydroxylamines in acids.
作者:MASAMI KAWASE、YASUO KIKUGAWA
DOI:10.1248/cpb.29.1615
日期:——
Alkylhydroxylamines having a benzene ring in the molecule were subjected to intramolecular cyclization in trifluoroacetic acid or in the presence of Lewis acids, and benzenefused six-membered heterocycles were obtained in moderate yields from the cyclization reaction of O-acylhydroxylamines. The effect of a methoxyl group on the benzene ring was also investigated. The m-methoxy compound (1j) cyclized to give 6-methoxy-2-methyl-1, 2, 3, 4-tetrahydroquinoline (2e), while the p-methoxy compound (1k or 1l) cyclized to give the same product (2e). These unusual results could be explained in terms of a spiro-intermediate (3a).
具有苯环的烷基羟胺在三氟乙酸或路易斯酸存在下进行分子内环化反应,由O-酰基羟胺的环化反应中等收率地得到了苯并融合的六元杂环。还研究了甲氧基在苯环上的影响。间甲氧基化合物(1j)环化得到6-甲氧基-2-甲基-1,2,3,4-四氢喹啉(2e),而对甲氧基化合物(1k或1l)环化得到相同产物(2e)。这些异常结果可以用螺环中间体(3a)来解释。