Triethylamine → 1-[(2S,3S)-3-(N2-t-Butoxycarbonyl-L-asparaginyl)amino-2-hydroxy-4-phenylbutyryl]-N-t-butyl-L-prolinamide

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Reaction Steps

15.5 g (43.9 mmol) of the p-nitrophenyl ester of N2 -t-butoxycarbonyl-L-asparagine and 7.33 g (72.3 mmol) of triethylamine were added, whilst ice-cooling, to a solution of 12.7 g (36.6 mmol) of 1-[(2S,3S)-3-amino-2-hydroxy-4-phenylbutyryl]-N-t-butyl-L-prolinamide [prepared as described in step (c) above] in 100 ml of dimethylformamide, and the mixture was stirred overnight at room temperature. At the end of this time, the reaction mixture was poured into ice-water, after which it was extracted with methylene chloride. The organic extract was then washed with a 1N aqueous solution of sodium hydroxide, with a 10% w/v aqueous solution of citric acid and with a saturated aqueous solution of sodium chloride, in that order. The extract was then dried over anhydrous sodium sulfate, after which the solvent was removed by distillation under reduced pressure. The residue was recrystallized from a mixture of methylene chloride and hexane, to give 17.6 g of the title compound as a colorless powder, melting at 113°-115° C.

Provenance & Evidence