The behavior toward polyphosphoric acid of arylhydrazones of a few heterocyclic carbonyl compounds of the thiophene and indole series is described. The phenylhydrazone and 2, 6- dimethylphenylhydrazone of ethyl a-thienylglyoxylate gave ethyl 4-and 5-(4-aminoaryl)-a- thienylglyoxylate, arising from two different sigmatropic rearrangementa. The N, 3, 5- trimethylphenylhydrazone of 2-methylindole-3-carboxaldehyde afforded the 4-[4-( ...
