反应详情

Once dissolved, the racemic narwedine mixture is maintained at a temperature of 25° C. to 70° C., preferably 40° C. to 60° C., and the crystals of enantiomeric narwedine, enantiomeric galanthamine, or enantiomeric epigalanthamine in an amount of from 0.1% to 2%, preferably 0.2% to 1% by weight relative to the amount of narwedine to be resolved are added. If (-)-narwedine is to be produced, the crystals added here are either (-)-narwedine, (+)-galanthamine, or (+)-epigalanthamine. If the reaction is to produce (+)-narwedine, the crystal used here are (+)-narwedine, (-)-galanthamine or (-)-epigalanthamine. Since the end result of the next step (the reduction to (-)-galanthamine) is intended to be as free as possible of epigalanthamine and (+)-galanthamine, (-)-narwedine is the most preferred crystal to use to generate additional (-)-narwedine so long as it is available. The temperature is then dropped to 25° to 70° C., preferably 40° C. to 60° C. and held there for 5-24 hours, preferably 12-18 hours, most preferably about 16 hours.

1. dissolutionOnce dissolved
2. customto be produced
3. additionthe crystals added here