Synthetic uses of polyphosphoric acid and its ethyl ester. Part II. Syntheses of indolin-2(3H)-ones and imidazoquinolines
作者:E. B. Mullock、R. Searby、H. Suschitzky
DOI:10.1039/j39700000829
日期:——
Dialkylamino-substituted indolin-2(3H)-ones were prepared by cyclisation of the required mandelanilides with hot polyphosphoric acid. A new reagent (PPEt) obtained from polyphosphoric acid and ethanol produced imidazoquinolines from aminobenzimidazoles and β-keto-esters and a 1,8-naphthyridine from 2-aminopyridine and ethyl α-methylacetoacetate, reactions which could not be brought about by PPA. The