Direkte Abtrennung von (1 R ,2 R )‐2‐Amino‐1‐(4‐nitrophenyl)‐1,3‐propandiol durch Racemattrennung seines Konglomerates

The conglomerate being more soluble than its enantiomers is the sole racemic modification that can be resolved in a direct way. Some classical cases requiring a single operation are known and they have been defined as the simultaneous and separate crystallization of enantiomers 1) . Much better known is the resolution of enantiomers by a sequence of alternate crystallization which takes place in the resolution by entrainment 2) also appropriately called “seesaw method” 3) . ( IR,2R )‐2‐Amino‐1‐(4‐nitrophenyl)‐1,3‐propanediol. In an Erlenmeyer 250 ml flask with a reflux condenser 4.8 g (0.025 mol) of quinic acid and 10.6 g (0.05 mol) of (1 RS ,2 RS )‐2‐amino‐1‐(4‐nitrophenyl)‐1,3‐propanediol were dissolved in 110 ml of methanol by heating at reflux for a few min. The clear solution so obtained was left overnight at room tem. (20–24°C).