One-pot synthesis of quinolin-2-(1 H )-ones via tandem Ugi–Knoevenagel condensations
摘要:
A new application of the Ugi reaction in the synthesis of heterocyclic compounds is described. Substituted quinolin-2- (1H)-ones are formed in one-pot sequential Ugi four-component condensation and intramolecular Knoevenagel cyclization between o-acylanilines. aldehydes. malonic or tosylacetic acids and cyclohexyl isocyanide. (C) 2004 Elsevier Ltd. All rights reserved.
Pyridine-2-carboxaldehyde, indole-3-carboxaldehyde, furfural, and p -acetylamino-benzaldehyde gave only polymers when subjected to Mannichreaction conditions in the presence of arylsulfonylacetic acids and ammonium acetate or cyclohexylamine. trans -Cinnamaldehyde, benzaldehyde, p -methoxy-, p -chloro-, p -isopropyl-, 3,4-methylenedioxy-, and 3,4-dimethoxybenzaldehyde were all successful in the condensation