Synthesis and reactions of 5-acetyl-2-amino-3-cyano-4-(5-X-2-furyl)-6-methyl-4H-pyrans

Abstract

Substituted 2-amino-4-(5-X-2-furyl)-4 H -pyrans IIIa-IIIe have been prepared by a cyclization reaction of 5-X-2-furylmethylenepropanedinitriles IIa-IIe with 2,4-pentanedione. In reaction of 3-(5-X-2-furyl)-methylene-2,4-pentanediones Ia-Ie with propanedinitrile the formation of 4 H -pyrans IIIa-IIIe is accompanied, depending on the catalyst type, by the formation of 5-X-2-furylmethylenepropanedinitriles IIa-IIe . 2-(4-Methylbenzylideneamino)-4 H -pyran ( V ), 2-formylamino-4 H -pyran ( VI ), and 3 H , 5 H -pyrano[2,3- d ]pyrimidine-4-one ( VII ) have been synthesized by functional modifications of the amino group in 4 H -pyran IIIa . The transformation of 4 H -pyran ring into pyridine ring gives - from 4 H -pyran IIIa - 5-acetyl-3-cyano-4-(2-furyl)-6-methyl-3,4-dihydro-2(1 H )-pyridone ( VIII ) and 5-acetyl-2-amino-3-cyano-4-(2-furyl)-6-methylpyridine ( IX ). The structure of synthesized compounds III-IX has been proved by means of IR, UV, and NMR spectra.