Synthesis of Quinoline‐4‐carboxamides and Quinoline‐4‐carboxylates via a Modified Pfitzinger Reaction of N‐Vinylisatins

Abstract

A synthetic approach for the accelerated assembly of quinoline-4-carboxamide and quinoline-4-carboxylate nuclei is presented. The methodology is based on the rearrangement of N-vinylisatins promoted by different types of amines (or ethanol) in a Pfitzinger-type mechanism that, in turn, builds the quinoline ring system. The reaction took place only by heating the starting materials in ethanol, without any additive.

Visible-light-induced synthesis of 2,4-disubstituted quinolines from o-vinylaryl isocyanides and oxime esters

“…1 For example, quinoline compounds are widely used in pharmaceuticals, dyes, photosensitive materials, and so on. 2 The traditional methods for building quinoline skeletons include the Gould–Jacobs reaction, 3 the Pfitzinger reaction, 4 the Friedländer reaction, 5 the Doebner–von Miller reaction, 6 the Combes/Conrad–Limpach reaction, 7 etc . 8 However, most of these methods involve harsh reaction conditions and tedious post-processing procedures and show poor regioselectivity and poor functional group compatibility.…”