63547-22-8

White Crystalline Powder

Intermediate in the preparation of Modafinil

General procedure for the synthesis of 2-[(diphenylmethyl)mercapto]acetic acid from diphenylmethanol and mercaptoacetic acid: mercaptoacetic acid (10.5 g, 7.92 mL, density = 1.325 g/mL, 0.114 mol) was added slowly and dropwise to a solution of trifluoroacetic acid (100 mL) in diphenylmethanol. During the dropwise addition, precipitate formation was observed within 30 minutes. The reaction mixture was stirred continuously for 3 hours at room temperature. Upon completion of the reaction, the precipitate was collected by filtration and washed sequentially with water (3 x 50 mL) and hexane. The crude product was purified by recrystallization from EtOAc/hexane mixed solvent to give colorless crystals of 2-[(diphenylmethyl)thio]acetic acid. Yield: 17.93 g (64% yield). Melting point: 121°C.

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