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[摘要]:Michael acceptor-possessing N-phenylcarbodiimides, which were prepared by an aza-Wittig reaction of the corresponding functionalized iminophosphoranes with aromatic and aliphatic isocyanates, reacted with enolate carbon-nucleophiles of active methylene compounds via the tandem cumulene addition-hetero (NH) Michael addition cyclization, to provide 2,3,4-trisubstituted 3,4-dihydroquinazolines. It was also found that 2-aminoquinolines and 2-amino-3,4-dihydroquinolines were competitively formed in some cases. Based on these observations, possible mechanistic pathways leading to these heterocycles are proposed. |
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