Synthesis of 4-Hydroxy-3-quinolinecarboxylic Acid Derivatives by a Condensation/Cyclization Sequence between<i>o</i>-Isocyanobenzoates and Magnesium Enolates
Addition of magnesium ester and amide enolates, generated using an excess amount of a magnesium amide (from diisopropylamine and ethylmagnesium bromide), to o-isocyanobenzoates affords 4-hydroxy-3-quinolinecarboxylic esters and amides by a tandem Claisen-type condensation/cyclization sequence.