Cycloaddition of Carbodiimides with a Heteroaromatic Substituent to Allenic Acids
作者:Latchezar S. Trifonov、Nadja I. Christova、Valentin S. Dimitrov、Alexander S. Orahovats
DOI:10.1002/hlca.19920750426
日期:1992.6.24
Cycloaddition of the allenic acid 3 with the N -cyclohexyl-N′ -heteroaromatic carbodiimides 2a and 2b gave the isomeric pyrido[1,2-a]pyrimidinones 4 and 5 and thiazolo[3,2-a]pyrimidinones 6 and 7, respectively, instead of the expected Diels-Alder adducts analogous to 1. The compounds of the latter type, i.e.8 and 9, were formed from 3 and carbodiimides 2c and 2d, respectively, containing an N′-(pyrazin-2-yl)
将烯丙酸3与N-环己基-N'-杂芳族碳二亚胺2a和2b环加成,分别得到异构体吡啶并[1,2- a ]嘧啶酮4和5以及噻唑并[3,2- a ]嘧啶酮6和7。而不是预期的Diels - Alder加合物类似于1。后一种类型的化合物,即8和9,是由3和碳二亚胺2c和2d分别包含N '-(吡嗪-2-基)或N '-(嘧啶-2-基)取代基。