Lipoic acid → 2-(dimethylamino)ethyl (R)-5-(1,2-dithiolan-3-yl)pentanoate

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Reaction Steps

A solution of DCC (11 g, 53 mmol) in anhydrous CH2Cl2 (20 mL) was added with stirring over 10-20 minutes to a cold (0° C.) solution of R-lipoic acid (10.0 g, 48.5 mmol), N,N-dimethylethanolamine (14.5 mL, 145 mmol, 3 eq.), and DMAP (600 mg, 4.9 mmol) in anhydrous CH2Cl2 (50 mL). Following complete addition, the cold bath was removed. After 18 hours at room temperature, all volatiles were removed under reduced pressure, and the resulting residue was purified by flash column chromatography (SiO2, 2% MeOH in CH2Cl2) providing the desired product as a clear yellow oil (10.6 g, 79%). All data consistent with values reported in the literature. (See Courvoisier C. et al. 2006. Synthesis and effects of 3-methylthiopropanoyl thiolesters of lipoic acid, methional metabolite mimics. Bioorganic Chemistry 34(1):49-58.)

Provenance & Evidence