Hydrochloric Acid → 239075-86-6

Participants

Reaction Conditions

Reaction Steps

25 g N-acetyl-indoline-2-carboxylic acid (purity 96.5%) was dissolved in 300 ml absolute EtOH while being heated to 70° C. and with mechanical stirring. 17.25 g/0.69 eq. (1R,2R)-1-(4-nitrophenyl)-2-amino-1,3-propanediol (99.5% chemically pure, [a]20D =-28.5° (c=0.4, 1N HCl)) was dosed in portions in 30 min. at 66-70° C. Spontaneous crystallization occurred. After 30 minutes' subsequent stirring at 69-70° C., cooling to 18° C. took place in 2.5 hours, followed by another 30 minutes' stirring. After filtration over a P4 glass filter 3 washings with 30 ml EtOH took place. After air-drying, 20.7 g yellow (S)-N-acetyl-indoline-2-carboxylic acid-(1R,2R)-1-(4-nitrophenyl)-2-amino-1,3-propanediol salt was obtained, corresponding to a yield of 42.0%. Enantiomeric excess=95.9% (chiral HPLC).

Provenance & Evidence