Some reactions of 3-cyano(diethylaminocarbonyl, methoxycarbonyl) pyridines with organolithium reagents. Synthesis of stabilized 1,2-, 1,4-, and 1,6-dihydropyridines

Abstract

The reaction of 3-cyano 5a, 3-diethylaminocarbonyl 5b, and 3-methoxycarbonylpyridine 5c with alkyllithiums 6 has been investigated as a method of preparing stable dihydropyridines. Reaction of 5a with 6 affords a mixture of 1,2- and 1,6-dihydropyridines 10 and 11, whereas reaction of 5b and 5c with 6 yields a mixture of 1,4- and 1,6-dihydropyridines 11 and 12. The cyano and diethylaminocarbonyl substituents of 5a and 5b are relatively resistant toward attack by the alkyllithium whereas reaction of the methoxycarbonyl substituent of 5c is competitive with addition to the ring. The stabilities of the dihydropyridines prepared are described.