Studies on seven-membered heterocycles. XXXIII. Synthesis of fully unsaturated 1,2,5-triazepines by photochemical ring expansion of 4-azidopyridazines.
作者:Hiroyuki SAWANISHI、Shuichi SAITO、Takashi TSUCHIYA
DOI:10.1248/cpb.38.2992
日期:——
Photolysis of the 3-methoxy-4-azidopyridazines (11) in the presence of a base such as methoxide ion and diethylamine resulted in ring-expansion to produce the 1H-1, 2, 5-triazepines (12 and 27), which were too unstable to be isolated, but tautomerized to the stable 4H-isomers (13 and 28) on further treatment with sodium methoxide and were converted to the stable 1-acetyl-1H-1, 2, 5-triazepines (14 and 29) by acetylation with acetyl chloride. The products 12-14 and 27-29 are the first examples of fully unsaturated 1, 2, 5-triazepines and were characterized by means of spectral analyses and some chemical reactions.
在甲氧基离子和二乙胺等碱存在下,3-甲氧基-4-叠氮哒嗪(11)发生光解,产生环状膨胀,生成 1H-1,2,5-三氮杂卓(12 和 27)、但在用甲醇钠进一步处理时,它们会同构化为稳定的 4H 异构体(13 和 28),并通过乙酰氯乙酰化转化为稳定的 1-乙酰基-1H-1,2,5-三氮杂卓(14 和 29)。产物 12-14 和 27-29 是完全不饱和的 1、2、5-三氮杂卓的第一个例子,并通过光谱分析和一些化学反应进行了表征。