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

Participants

Reaction Steps

A solution of 19 g of (E)-2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenyl-3-butenyl]-4-methylvaleric acid in 220 ml of dimethylformamide was cooled to 0° C. and was treated in succession with 9.22 g of benzyl carbamate, 8.43 g of 1-hydroxybenzotriazole, 7.05 ml of N-methylmorpholine and 11.7 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The mixture was allowed to warm to room temperature and was then stirred overnight. The solvent was evaporated and the residue was partitioned between ethyl acetate and 5% aqueous citric acid solution. The ethyl acetate layer was washed with 5% sodium hydrogen carbonate and saturated sodium chloride solution. After drying over anhydrous magnesium sulphate the ethyl acetate was evaporated and the residue dissolved 200 ml of methanol and 2.5 g of 10% palladium-on-charcoal added. The mixture was shaken in a hydrogen atmosphere for 4 hours and then the catalyst was removed by filtration. The methanol was evaporated and the residue stirred with hexane and filtered. There was obtained 17.41 g of 2(R)-[1(S)-(tert-butoxycarbonyl)-4-phenylbutyl]-4-methylvalerohydrazide in the form of a white solid.

Provenance & Evidence