4-Methylmorpholine → (3R)-6-Cyclohexyl-N-hydroxy-3-(3-{[3-(4-morpholinyl)-1-azetidinyl]carbonyl}-1,2,4-oxadiazol-5-yl)hexanamide

Participants

Reaction Conditions

Reaction Steps

A solution of (3R)-6-cyclohexyl-3-(3-{[3-(4-morpholinyl)-1-azetidinyl]carbonyl}-1,2,4-oxadiazol-5-yl)hexanoic acid trifluoroacetate (Preparation 28) (1173 mg, 2.70 mmol) and N-methylmorpholine (327 μl, 2.97 mmol) in N,N-dimethylformamide (25 ml) was cooled to 0° C., treated dropwise with isobutyl chloroformate (386 μl, 2.97 mmol) and stirred under a nitrogen atmosphere at 0° C. for 45 minutes. Hydroxylamine hydrochloride (564 mg, 8.11 mmol) was then added followed by further N-methylmorpholine (891 μl, 8.11 mmol) and the mixture was stirred for 18 hours being allowed to warm to room temperature over this time. The solvent was removed under reduced pressure and the residue dissolved in a saturated aqueous solution of sodium carbonate. The pH of the solution was adjusted to 9 by dropwise addition of acetic acid. Water was added (75 ml) and the product was then extracted with ethyl acetate (×2). The combined organic phases were washed with brine, dried over anhydrous sodium sulphate, filtered and the solvent removed under reduced pressure. The residue was purified by column chromatography on silica gel eluting with a gradient system of dichloromethane:methanol:0.88 ammonia (90:10:1) then dichloromethane:methanol:0.88 ammonia (80:20:2). The product was further purified by HPLC to afford the title compound as a white solid (151 mg)

Provenance & Evidence