Polyfluoroheterocyclic compounds. Part IX. Tautomerism in polyfluorohydroxy-quinolines and -isoquinolines

Abstract

Heptafluoroquinoline with aqueous sodium hydroxide or with potassium hydroxide in t-butyl alcohol gives a mixture of 2- and 4-hydroxyhexafluoroquinolines; heptafluoroisoquinoline reacts to give the 1-hydroxy-derivative. 2-Hydroxyhexafluoroquinoline and 1-hydroxyhexafluoroisoquinoline exist as tautomers and react with diazomethane giving a mixture of O- and N-methyl derivatives whereas 4-hydroxyhexafluoroquinoline gives only an O-methyl derivative. The factors affecting tautomerism in these systems are outlined.