Synthesis
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.
References
[1] Journal of Medicinal Chemistry, 1993, vol. 36, # 20, p. 2984 - 2997
[2] Tetrahedron Asymmetry, 2004, vol. 15, # 6, p. 1053 - 1058
[3] Tetrahedron Asymmetry, 2005, vol. 16, # 21, p. 3507 - 3511
[4] Patent: US7553646, 2009, B2
[5] Molecules, 2012, vol. 17, # 9, p. 10446 - 10458