Acetals of lactams and acid amides. 39. Synthesis of three-ring derivatives of pyrido [l,2-a] pyrimidines on the basis of the reaction of dimethylformamide acetal with dicyanomethylenecycloalkanes
Acetals of lactams and acid amides. 39. Synthesis of three-ring derivatives of pyrido [l,2-a] pyrimidines on the basis of the reaction of dimethylformamide acetal with dicyanomethylenecycloalkanes
Improved Synthesis of Mono- and Disubstituted 2-Halonicotinonitriles from Alkylidene Malononitriles
作者:Ashley R. Longstreet、Brian S. Campbell、B. Frank Gupton、D. Tyler McQuade
DOI:10.1021/ol4025265
日期:2013.10.18
with 2,3,4 and/or 5 substitution remain challenging to prepare. Existing strategies to form multisubstituted 2-halonicotinonitriles via enamines suffer from dimerization of the starting alkylidenemalononitriles resulting in low yields. Through alteration of reaction conditions, a new high yielding method into enamines was realized by condensing DMF–DMA and alkylidenemalononitriles in the presence of