4-Methylmorpholine → 2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenylbutyl]-4-methylvalerohydrazide

Participants

Reaction Conditions

Reaction Steps

A solution of 4.8 g of 2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenylbutyl]-4-methylvaleric acid in 50 ml of dimethylformamide was cooled to 0° C. and treated with 2.80 g of pentafluorophenol and 2.65 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The mixture was stirred at 0° C. for 2.5 hours and then treated with 4.73 g of hydrazine monohydrochloride and 6.97 g of 4-methyl morpholine. The mixture was stirred for a further 18 hours at room temperature and then evaporated. The residue was dissolved in ethyl acetate and washed sequentially with 2M aqueous hydrogen chloride, 5% aqueous sodium hydrogen carbonate, water, and saturated aqueous sodium chloride. The organic layer was dried over anhydrous magnesium sulphate and evaporated. The residue was purified by flash column chromatography on silica gel using ethyl acetate/hexane (1:1) as the eluant to give 2.18 g of 2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenylbutyl]-4-methylvalerohydrazide in the form of a pale yellow solid.

Provenance & Evidence