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 (H4SiW12O40) 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