L-Hydroxyproline → 1-(Phenylmethyl) (2S,4R)-4-hydroxy-1,2-pyrrolidinedicarboxylate

Participants

Reaction Conditions

Reaction Steps

Sodium bicarbonate (131.04 g) was dissolved in water (1040 ml), and trans-4-hydroxy-L-proline (78.6 g) was added thereto. To the resultant mixture, a solution of benzyloxycarbonyl chloride (72 ml) in dry toluene (320 ml) was added, and the mixture was stirred at an inner temperature of 28° C. for 3 hours. Sodium bicarbonate (65.52 g) and benzyloxycarbonyl chloride (72 ml) were additionally added thereto, and stirring was continued at the same temperature for 2 hours. The reaction mixture was washed with ether, and the aqueous layer was filtered. The filtrate was washed again with ether. The aqueous layer was adjusted to pH 1 with 6N hydrochloric acid and extracted with ethyl acetate. The extract was washed with aqueous sodium chloride solution, dried over sodium sulfate and concentrated to remove the solvent to give trans-1-benzyloxycarbonyl-4-hydroxy-L-proline.

Provenance & Evidence