Synthesis of 3-Aminopyrocatechol via Lithiated Intermediates

Abstract

We report the synthesis of 3-aminopyrocatechol (7) through electrophilic amination of lithiated pyrocatechol, protected in the form of a ketal. For this purpose the lithiation reaction of protected pyrocatechol (1) was studied. The synthesis of compounds (3) was achieved by the reaction of organolithium derivative (2) and a series of electrophilic reagents. Lithium-t-butyl-N-tosyloxycarbamate (5) was used as the electrophilic aminating reagent. With the cupro derivative (4) the protecting groups in compound (6) are removed in an acid medium by heating in ethanol-HCl solution (4:1).