PREPARATION METHOD OF THIOSALICYLIC ACID(OR 2-MERCAPTOBENZOIC ACID)

摘要

PURPOSE: A preparation method of thiosalicylic acid by deoxidization-hydrolysis of 2-cyanobenzenesufonyl chloride and reduction-hydrolyzing is provided which increases yields of thiosalicylic acid without separate complicate purification process. CONSTITUTION: Thiosalicylic acid is prepared by reducing a compound(I) using zinc and acetic acid of 1: 4 - 1: 6 and hydrolyzing using water and hydrochloric acid of 1: 4 - 1: 6 at -10 to 130°C. For example, 2g 2-benzoic sulfimide and 3g phophorus pentachloride are melted in 15 ml solvent slowly, stirred for 10 min, added with 2g zinc chloride, reduced for 1 hr, cooled, added with ice water, extracted with chloroform or ether, and dried with anhydrous magnesium sulfate to give 2-cyanobenzenesufonyl chloride(yield 90%). The compound is useful as a precursor of thioxanthone in a photochemical field and a synthetic intermediate(syphon) in an agricultural chemical field.