Hydrochloric Acid → 239075-86-6

Participants

Reaction Conditions

Reaction Steps

200 g N-acetyl-indoline-2-carboxylic acid (purity 96.5%) was dissolved in 1760 ml of a mixture containing 90% EtOH, 5% water and 5% MeOH, with heating to 76° C., and with mechanical stirring. 138 g/0.69 eq (1R,2R)-1-(4-nitrophenyl)-2-amino-1,3-propanediol (99.5% chemically pure, [a]20 D =-28.5° (c=0.4, 1N HCl)) was dosed in portions in 30 min. at 73-76° C. After cooling to 70° C., grafting with 1 g S-salt took place, followed by cooling to 15° C. in 3 hours and 30 minutes' subsequent stirring. After filtration over a P4 glass filter, 3 washings with 200 ml EtOH took place. After air-drying, 158.1 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 40.3%. Enantiomeric excess=99.0% (chiral HPLC).

Provenance & Evidence