Abstract 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)- ...