L-Tartaric acid → D-Tartaric acid

Participants

Reaction Conditions

Reaction Steps

73.6 g (0.34 mol) of cis-8-benzyl-2,8-diazabicyclo[4.3.0]nonane dissolved in 111 ml of dimethylformamide is added a drop at a time to a solution of 102.9 g (0.685 mol) of L(+)-tartaric acid in 343 ml of dimethylformamide. The batch is seeded with [R,R]-8-benzyl-2,8-diazabicyclo[4.3.0]nonane L-tartrate and gradually cooled to an interior temperature of 18° C. The crystals are suctioned off and the filtrate seeded with [S,S]-8-benzyl-2,8-diazabicyclo[4.3.0]-nonane L-tartrate and agitated until it crystallizes completely. ([S,S]-8-benzyl-2,8-diazabicyclo[4.3.0]nonane D-tartrate can be obtained from the mother liquor subsequent to concentration and release of the base by purification with D(-)-tartaric acid as described for Method I.) The product is suctioned off, washed with dimethylformamide and isopropyl alcohol, and dried in the air. The crystals are recrystallized from 88% ethanol. 52 g of [S,S]-8-benzyl-2,8-diazabicyclo[4.3-O]nonane L-tartrate trihydrate are obtained.

Provenance & Evidence