150301-54-5Relevant academic research and scientific papers
The aza-ene or the Michael addition? Examination of an unusual substituent effect on the reaction of heterocyclic ketene aminals with ethyl propiolate
Zhao, Mei-Xin,Wang, Mei-Xiang,Huang, Zhi-Tang
, p. 1309 - 1316 (2007/10/03)
Heterocyclic ketene aminals having at least one secondary amino group underwent the aza-ene reaction with ethyl propiolate under various conditions to yield the corresponding adducts, which were readily transformed into the δ-lactam fused heterocyclic products with or without the aid of sodium ethoxide in refluxing ethanol, while the ester- and cyano-substituted tertiary enediamines acted as the strong Michael donor to add to ethyl propiolate in a polar or a protic solvent. The unusual substituent effect on the reactivity and mechanism was discussed.
Further Investigation on the Reaction of Heterocyclic Ketene Aminals with Ethyl Propiolate: Ene-type Reaction of Enamines and an Unusual Substituent Effect
Huang, Zhi-Tang,Wang, Mei-Xiang
, p. 1085 - 1090 (2007/10/02)
The reaction between heterocyclic ketene aminals and ethyl propiolate 1 has been investigated and an unusual substituent effect observed.Although 2-(benzoylmethylene)-1,3-dimethylimidazolidines 2 failed to add to 1,2-(benzoylmethylene)imidazolidine 3 reacted with it to give the fused heterocycle 5 via the intermediate 4.With one methylated nitrogen, the heterocyclic ketene aminals 6 or 7 reacted with 1 to afford the heterocyclic compounds 9 or 10 and ethoxycarbonylvinyl substituted heterocycles 11 or 12.By controlling the reaction conditions, 9 or 10 and 11 or 12 can be synthesized selectively.The results are interpreted in terms of a n ene-addition mechanism with steric interaction in the intermediates.A correlation between reactivity and intramolecular hydrogen bonding is also discussed.
