(3S,4R)-4-amino-3-hydroxy-2,2-dimethyl-chroman-6-carbonitrile → (3S,4R)-4-amino-3-hydroxy-2,2-dimethyl-chroman-6-carbonitrile

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Reaction Steps

A mixture of trans-4-amino-3,4-dihydro-2,2-dimethyl-3-hydroxy-2H-1-benzopyran-6-carbonitrile (193 g) and (-)-di-p-toluoyl-L-tartaric acid monohydrate (358 g) was dissolved in ethanol (600 ml) under reflux. The mixture was cooled to room temperature and stood for 3 days to give a white precipitate. This precipitate was collected by filtration, washed with a small volume of ethanol, and recrystallized twice from ethanol to give (-)-di-p-toluoyl-L-tartaric acid salt of (3S,4R)-4-amino-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile (43.1 g).

Provenance & Evidence