A Thermolytic Azulene Synthesis from Dimethyl 4-Morpholino-3,3a,8,8a-tetrahydroazulene-5,6-dicarboxylates and Its 1-Substituted Derivatives
作者:Shigeyasu Kuroda、Syuzi Hirooka、Mitsunori Oda、Hiroyuki Iwaki、Syuki Teranishi、Noriko Matsushita、Tamotsu Hongou、Mariko Ikeda、Syuichi Hayashi、Ryuta Miyatake、Mayumi Izawa、(the late) Masaki Yamada、Ichiro Shimao
DOI:10.1246/bcsj.71.459
日期:1998.2
The thermolysis of 1-substituted 4-morpholino-3,3a,8,8a-tetrahydroazulene-5,6-dicarboxylates derivatives (7a—c) under catalytic dehydrogenation conditions was studied. The reaction substrates were prepared by a several-step sequence involving the [2+2] cycloaddition of bicyclc morpholino enamines with dimethyl acetylenedicarboxylate, and a subsequent electrocyclic opening of the cyclobutene ring as
研究了 1-取代的 4-morpholino-3,3a,8,8a-tetrahydroazulene-5,6-dicarboxylates 衍生物 (7a-c) 在催化脱氢条件下的热解。反应底物通过多步序列制备,包括双环吗啉代烯胺与乙炔二羧酸二甲酯的 [2+2] 环加成,以及随后作为关键骨架结构的环丁烯环的电环开环,从双环 [3.3.0] 开始辛烷-2,6-二酮单(乙缩醛)。回流含有催化量 Pd–C 的 4-morpholino-3,3a,8,8a-tetrahydroazulene-5,6-dicarboxylate (7a) 的二苯醚溶液,得到 10% 的二甲基 azulene-5,6 -二羧酸酯 (8a),伴随有 10% 产率的 4,6-二羧酸二甲酯 (9a)、痕量的 5,7-二羧酸二甲酯 (10a),azulene-5-carboxylate 甲酯 (12a) 和 azulene-6-carboxylate