Sodium Tungstate Dihydrate (Na2WO4·2H2O): A Mild Oxidizing and Efficient Reagent in Organic Synthesis

[摘要] Sodium tungstate dihydrate (Na2WO4·2H2O) is a simple,cheap, commercially available, and water-soluble colorlesscrystalline solid inorganic material. It is synthesized whenexcess tungstic acid is added to aqueous sodium hydroxide,dehydrates at 100 °C, and is insoluble in ethanol. The aqueous solution is slightly alkaline (pH 8–9).1 The solid can bestored in a hermetically closed flask in a dry place. Thiscompound is usually used as an oxidizing agent in chemistry,2 affording the corresponding peracid in conjunctionwith hydrogen peroxide, under mild conditions, that canoxidize amines and sulfur-containing substrates (Scheme1).3 Sodium tungstate dihydrate is the most common hydrated form and can also be used as an efficient catalyst forepoxidation of alkenes and oxidation of alcohols into thecorresponding carbonyl compounds. For example, Payneand Williams described the first use of sodium tungstate dihydrate for epoxidation of ,-unsaturated acids.4 In addition, it can be used to form heterocycles. Table 1 presents aseries of recent applications of this reagent.

[学科分类] 精神健康和精神病学

[关键词] oxidation;sodium tungstate;inorganic reagents;organic synthesis