Acid catalysed reactions of 5-formyluracils with enamines. A facile synthesis of 5-acylvinyluracils
摘要:
5-Formyl-1,3-dimethyluracil (1) reacts with secondary amine derived enamines of ketones and aldehydes to provide 5-(acyvinyl)uracil derivatives. The presence of a CH3 group at C-6 of 1 induces a competitive annulation reaction. Depending on the bulk of substituents 5-(acylvinyl)uracils acquire cis -diene and E or Z configurations on the vinyl unit. Enamines derived from 1,3-cyclohexanedione and ethyl acetoacetate react with 1 in 1: 2 stoichiometric manner to provide 5-(9-xanthenyl)uracil and 5-(6-cycohexadienyl)uracil(X-ray) derivatives. (C) 1998 Elsevier Science Ltd. All rights reserved.
5-Formyl-1,3-dimethyluracil (1) reacts with secondary amine derived enamines of ketones and aldehydes to provide 5-(acyvinyl)uracil derivatives. The presence of a CH3 group at C-6 of 1 induces a competitive annulation reaction. Depending on the bulk of substituents 5-(acylvinyl)uracils acquire cis -diene and E or Z configurations on the vinyl unit. Enamines derived from 1,3-cyclohexanedione and ethyl acetoacetate react with 1 in 1: 2 stoichiometric manner to provide 5-(9-xanthenyl)uracil and 5-(6-cycohexadienyl)uracil(X-ray) derivatives. (C) 1998 Elsevier Science Ltd. All rights reserved.