Pentafluorophenol → (E)-2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methylvalerohydrazide

Participants

Reaction Conditions

Reaction Steps

A solution of 20 g of (E)-2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methylvaleric acid in 200 ml of dimethylformamide was cooled to 0° C. under nitrogen and treated with 11.8 g of pentafluorophenol and 12.3 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred for 2.5 hours at 0° C. and then treated with 19.8 g of hydrazine hydrochloride and 33 ml of triethylamine. The mixture was left to warm to room temperature and was then stirred overnight. Evaporation gave a residue which was dissolved in ethyl acetate and washed with 2M aqueous hydrogen chloride, 5% aqueous sodium hydrogen carbonate and saturated aqueous sodium chloride. Evaporation gave a solid which was washed with ether/hexane (1:1) and dried to give 12.1 g of of (E)-2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methylvalerohydrazide in the form of a white solid.

Provenance & Evidence