Collect. Czech. Chem. Commun. 1990, 55, 718-727

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

Štefan Marchalín, Dušan Ilavský, Jaroslav Kováč and Milan Bruncko

Department of Organic Chemistry, Slovak Technical University, 812 37 Bratislava


Substituted 2-amino-4-(5-X-2-furyl)-4H-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 4H-pyrans IIIa-IIIe is accompanied, depending on the catalyst type, by the formation of 5-X-2-furylmethylenepropanedinitriles IIa-IIe. 2-(4-Methylbenzylideneamino)-4H-pyran (V), 2-formylamino-4H-pyran (VI), and 3H, 5H-pyrano[2,3-d]pyrimidine-4-one (VII) have been synthesized by functional modifications of the amino group in 4H-pyran IIIa. The transformation of 4H-pyran ring into pyridine ring gives - from 4H-pyran IIIa - 5-acetyl-3-cyano-4-(2-furyl)-6-methyl-3,4-dihydro-2(1H)-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.