[¦par·ə ¦tä‚lil¦səl·fə‚nil¦meth·əl‚nī′trō·sə‚mīd] (organic chemistry) C8H10N2O3S Yellow crystals with a melting point of 62°C; soluble in ether, petroleum ether, benzene, carbon tetrachloride, and chloroform; a precursor to diazomethane; a useful reagent for the preparation of a wide range of biologically active compounds for gas chromatography analysis.