5-Aryl-2-furaldehydes in the Synthesis of 2-Substituted 1,3-Benzazoles

2-2-(5-Aryl-2-furyl)ethenyl]-1,3-benzazoles were synthesized by reaction of 5-aryl-2-furaldehydes with 2-methylbenzoxazole, 2-methylbenzothiazole, 2-methylbenzimidazole, and 2-cyanomethylbenzimidazole. The corresponding benzazoles were also obtained by reaction of N-(5-arylfurfurylidene)anilines with 2-methylbenzoxazoles and of 3-(5-aryl-2-furyl)-2-cyanopropenoyl chlorides with o-phenylenediamine. The acylation of o-aminophenol with 3-(5-aryl-2-furyl)-2-cyanopropenoyl chlorides occurs at the amino group without subsequent oxazole ring closure.