Synthesis of Mixed Aryl 2,3-Diarylsulphanyl-1,4-naphthoquinones

The reaction of 2-arylsulphanyl-1,4-napththoquinone with aromatic thiols and sodium dithionate leads to bis-2,3-(arylsulphanyl)naphthalene-1,4-diols in high yield. Corresponding oxidized products, namely 2,3-diarylsulphanyl-1,4-naphthoquinones, are prepared in near quantitative yield by a copper(II)-catalyzed aerial oxidation reaction of bis-2,3-(arylsulphanyl)naphthalene-1,4-diols under mild condition.