4]benzoxazine (13) only. The conformation of the dihydro-oxazine ring of several compounds has been studied by n.m.r. spectroscopy; vicinal coupling constants are deduced. The mass spectra of several 3,4-dihydro-1,4-benzoxazines, some of which contain a fused pyrone ring, are reported and interpreted.
具有脂肪族羰基取代基的硝基
色酮已被选择性还原为胺,这些胺可自发环化为二氢
吡喃并[2,3- f ]-和二氢
吡喃并[3,2- f ]-[1,4]苯并恶嗪(10)和(12)。经类似处理的叔丁基酮(5)仅得到
吡喃并[2,3- f ] [1,4]苯并恶嗪(13)。核磁共振波谱法研究了几种化合物的二氢恶嗪环的构象。推导相邻的耦合常数。报告并解释了几种3,4-二氢-1,4-苯并恶嗪的质谱,其中一些含有稠合的
吡喃环。