Ammonia → (S)-Benzyl-3-hydroxyglutaramate

Participants

Reaction Conditions

Reaction Steps

Tert-pentanol (800 ml) was saturated with ammonia gas to about 1.0-1.5 mole. To this dimethyl-3-hydroxy glutarate (100 g) was added followed by the addition of 3 g immobilized CAL-B (CAL B-T1-AMD2). The flask was closed and stirred at 20-25° C. After completion of reaction enzyme was removed by filtration and washed the enzyme with tert-pentanol (100 ml). The filtrate was evaporated under reduced pressure at a temperature below 50° C. to yield a residue. To this residue mixture of Benzyl alcohol (131.0 g), (S)-methyl-3-hydroxyglutaramate (100 g) and Tetraisopropyl orthotitanate (17.5 g) are mixed in a flask. The mixture was stirred under vacuum at 50-60° C. for about 5 hrs. The reaction mixture was cooled and diluted with isopropyl acetate (500 ml). The reaction mixture was added to a stirred solution of Tartaric acid (37 g in 370 ml DM water) and 500 ml isopropyl acetate mixture. The reaction mixture was stirred and pH was adjusted to 7.0-8.0 by Aq ammonia solution. Layers were separated. The organic phase was removed and the aqueous phase was extracted with isopropyl acetate. Combined organic layer was washed with Aq ammonia and tartaric acid solution followed by brine wash. The organic phase was dried over anhydrous sodium sulphate and evaporated under reduced pressure to yield oil. To this oil tert-butyl methyl ether (800 ml) was added, stirred, cooled, filtered and dried to give (S)-Benzyl-3-hydroxyglutaramate.

Provenance & Evidence