NOVEL PREPARATION OF NITROGEN-CONTAINING AROMATIC 2-MERCAPTO-N-OXIDE

PURPOSE:To prepare the titled compound useful as a raw material of fungicide, cosmetics, etc., in a short process, with simple operation, under mild reaction conditions, by reacting a specific compound with elemental sulfur, etc. in a solvent in the presence of a phase transfer catalyst and a metal hydroxide. CONSTITUTION:The objective compound of formulaIcan be prepared by reacting the compound of formula II (R -R are H, alkyl or aryl; R and R may together form a benzene ring), e.g. pyridine N-oxide, gamma-picoline N-oxide, etc. with a sulfur source selected from elemental sulfur, sulfur-containing metallic salts, mercapto-containing compounds, and mercapto-producing compounds, in water, organic solvent or a mixture of water and organic sovent, in the presence of a phase transfer catalyst such as 18-crown-6, etc. and a metal hydroxide such as NaOH, at 30-250 deg.C for 0.5-several tens hours, thereby directly introducing the sulfur source to the starting compound. EFFECT:An inexpensive metal hydroxide can be used, and the phase transfer catalyst can be recovered and reused.