Metal-/catalyst-free one-pot three-component thioamination of 1,4-naphthoquinone in a sustainable solvent

Abstract

A metal-/catalyst-free protocol for the direct thioamination of 1,4-naphthoquinone with thiophenols and amines using air as an oxidant in a green solvent has been developed. This environmentally friendly strategy was realized using commercially available reagents with simple operation under mild conditions affording 2-amino-3-thio-1,4-naphthoquinones as products in moderate to good yields. Importantly, the use of cyclopentyl methyl ether (CPME) as a solvent could eliminate the need for traditional amide solvents with tedious post-treatment. Additionally, the potential utility of this protocol was further demonstrated by a gram-scale experiment.