We report the synthesis of N-benzyl-N-[(E)-buta-1,3-dienyl]propanamide (6) and its corresponding O-silyl-subitituted ketene N,O-acetal 7 and their Diels-Alder reaction. Propanamide G reacted smoothly, whereas the yield obtained from 7 was low, probably due to polymerization of the dienophile induced by electron transfer. The ketene N,O-acetals 27a-g were synthesized starting from the corresponding benzamides 25a-e (Scheme 9). The ketene N,O-acetals 27a-g showed increased stabilities and underwent amino-Claisen rearrangements under thermal conditions. Using catalysts, interesting side reactions leading either to the annulated systems, rac-35-37 or to a beta -lactam rac-34 were observed.
We report the synthesis of N-benzyl-N-[(E)-buta-1,3-dienyl]propanamide (6) and its corresponding O-silyl-subitituted ketene N,O-acetal 7 and their Diels-Alder reaction. Propanamide G reacted smoothly, whereas the yield obtained from 7 was low, probably due to polymerization of the dienophile induced by electron transfer. The ketene N,O-acetals 27a-g were synthesized starting from the corresponding benzamides 25a-e (Scheme 9). The ketene N,O-acetals 27a-g showed increased stabilities and underwent amino-Claisen rearrangements under thermal conditions. Using catalysts, interesting side reactions leading either to the annulated systems, rac-35-37 or to a beta -lactam rac-34 were observed.
Generalization of the Benzotriazole-Mediated Introduction of N-Substituents into Amides
作者:Alan R. Katritzky、Alexey V. Ignatchenko、Hengyuan Lang
DOI:10.1021/jo00118a015
日期:1995.6
N-(Benzotriazol-1-ylmethyl) amides 2, easily available by condensation of BtCH(2)OH with amides, are used for the preparation of a variety of N-substituted amides such as the homoallyl, 1,3-butadienyl, and 2,2-diphenylcyclopropyl derivatives by displacement of the benzotriazole group under different conditions.