Ring transformations of 2-morpholinofurans and N-(2,3-dihydro-2-furylidene)morpholinium salts
Abstract
N-(3-Arylmethylene-2,3-dihydro-5-phenyl-2-furylidene)morpholiniurn perchlorates (2) reacted with hydrazine to yield 4-arylmethyl-3-morpholino-6-phenylpyridazines (3), 3-arylazo-2-morpholino-5-phenylfurans (9) similarly gave 4-(2-arylhydrazino)-3-morpholino-6-phenylpyridazines, and 2-morpholino-5-phenylfuran formed hydrazonotetrahydropyridazines (13) and (14). The alkoxydihydrofurans (6a and b) were obtained by the action of alcohols in the presence of bases on N-(2,3-dihydro-5-phenyl-3-diphenylcyclopropenylidene-2-furylidene)morpholinium perchlorate (5). The hydrofluoroborate of 2-morpholino-5-phenyl-3-phenylazofuran rearranged to the morpholide of 1,5-diphenylpyrazole-3-carboxylic acid on treatment with hydrochloric acid.