Photooxidation of several mesoionic compounds gave ring cleavage products, some of which were apparently formed via the endoperoxides of the mesoionicrings. Photooxidation of a Δ2-oxazolin-4-one and a Δ2-thiazolin-4-one gave the corresponding 4,4′-bisoxa- and bisthiazolinone in dichloromethane, whereas the former gave benzamide in dimethylformamide.
Quaternarisation de l'atome d'azote de systemes tautomeres de la serie des oxo-4 thiazoles. Cycloadditions dipolaires 1,3 des thiazoles mesoioniques formes in situ
作者:A. Robert、M. Ferrey、A. Le Maréchal
DOI:10.1016/s0040-4020(01)83124-0
日期:1980.1
behaviour to azlactones. However, the mechanism of their reaction with dimethylacetylenedicarboxylate or with ethyl vinyl ether differs fundamentally. In the thiazole series, the first step is the quaternization of the nitrogen atom. The mesoionic thiazole intermediate is then trapped by a second molecule of the dipolarophile.
Reaction de Cycloaddition dipolaire-1,3-des thiazolones et des selenazolones mesoioniques avec l'acetylene dicarboxylate de methyle—II
作者:M. Baudy、A. Robert、C. Guimon
DOI:10.1016/0040-4020(82)85160-0
日期:1982.1
Mesoionic thiazolones and selenazolones react with dimethyl acetylene dicarboxylate to give thiophenes or pyridones. We show that the reactivity of the mesoionic thiazolones towards dimethyl acetylene dicarboxylate may be explained by second order perturbation theory, limited to frontier orbitals. The influence of the temperature and of the nature of the substituants on the evolution of the primary