Application of Organolithium Compounds in Organic Synthesis. XIX. Synthetic Strategies Based on Aromatic Metallation. A Concise Regiospecific Synthesis of 3-Halogenated Picolinic and Isonicotinic Acids

Abstract

The synthesis of the halogenated picolin- and isonicotinanilides (3) and (4) via metallation (n-BuLi) of the anilides (1) and (2) and then the reaction of the generated bis-lithiated anilides with halogenating agents (CCI₃-CCI₃, CH₂Br-CH₂Br, I₂) followed by subsequent acidic hydrolysis of (3) and (4), as a way of regiospecific transformation of picoline and isonicotine acids into their C³-halogenated derivatives, is described.