Formation of arylacetic acids, arylacetamides, and aryldihydropyrroles from aromatic aldehydes

Abstract

Furfuraldehyde, 4-hydroxybenzaldehyde, and 4-hydroxy-3-methoxybenzalde- hyde were converted into 2-furylacetic, 4-hydroxyphenylacetic and 4- hydroxy-3-meth-oxyphenylacetic acids respectively on reaction with glyoxal bisulphite and cyanide in alkaline solution. Under the same reaction conditions, 2-hydroxybenzaldehyde yielded 2- hydroxyphenylacetic acid and 3-(2?-hydroxypheny1)-2H-chromen-2-one. When ammonia was present in the reaction mixture, furfuraldehyde and 4- hydroxy-benzaldehyde formed 2-furylacetamide and 4- hydroxyphenylacetamide respectively. Alternatively, in the presence of methylamine, furfuraldehyde yielded 5-(2?-furyl)-2-imino-1-methyl-2,5- dihydropyrrole-3,4-diol and benzaldehyde gave the corresponding phenyldihydropyrrolediol.