3-Amino-5-hydroxybenzoic acid in antibiotic biosynthesis. VIII. Synthesis of chlorinated analogues

Abstract

The three isomeric ring monochlorinated derivatives of 3-amino-5-hydroxybenzoic acid (1), required for studies of the biosynthesis and synthesis of several important classes of antibiotics, are prepared from methyl 3-amino-5-hydroxybenzoate (5). N-Chlorosuccinimide selectively monochlorinates the 2- and 6-positions of this substrate, whilst perchlorination followed by hydrolysis and regiospecific protodechlorination at the 2- and 6-positions affords the 4-chloro acid.