Tungstosilicic acid (H4SiW12O40) have efficient catalysts for synthesis of 2,3-Dihydroxynaphthoquinone from lawsone

Abstract

The Thiele–Winter reaction is of interest for synthesis of tetracetoxyaromatic precursors of hydroxynaphtoquinones. Solid acids such as Tungstosilicic acid (H4 SiW12O40) have an efficient catalyst in acetoxylation reaction of naphtoquinones without the use of organic solvent at room temperature. 1,2,3,4-Tetrahydroxynaphthalene was easily oxidized at room temperature in 2,3-Dihydroxynaphthoquinone by using (Pc[Co]/K10) and air (1 atm). We have also tested this type of reaction in 2-hydroxynaphthoquinone (Lawsone). Many naphthoquinones are natural products with interesting biological properties