DL-Carnitine → (-)-Carnitine

참여 물질

반응 단계

A solution of 35.0 g (0.177 mole) of DL-carnitine hydrochloride in 300 ml of water is passed through OH type strongly basic resin (Dowex-1X8) and the solution is concentrated to give 28.0 g (0.173 mole) of DL-carnitine. To DL-carnitine are added 61.9 g (0.173 mole) of dibenzoyl-L(+)tartaric acid and 90 ml of methanol. The mixture is dissolved under heat to form dibenzoyl-L(+)tartarates of D-carnitine and L-carnitine. The tartarates are cooled from 60° C. to 5° C. over a period of 24 hours to fractionally crystallize L-carnitine dibenzoyl-L(+)tartarate. The tartarate is filtered and washed to give L-carnitine dibenzoyl-L(+)tartarate (yield 39.0 g, purity 92.7%). The tartarate obtained is dissolved under heat in 190 ml of ethanol, and cooled from 60° C. to 25° C. over a period of 24 hours. This recrystallization gives 21.5 g of crystals of L-carnitine dibenzoyl-L(+)tartarate. [α]D25 =-96.2° (c= 1, MeOH), m.p. 154° C. (dec.), purity 99.7%.

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