4-Methylmorpholine → Ethyl 3-(5-{(1R)-4-cyclohexyl-1-[2-(hydroxyamino)-2-oxoethyl]butyl}-1,2,4-oxadiazol-3-yl)propanoate

A solution of 3R)-6-cyclohexyl-3-[3-(3-ethoxy-3-oxopropyl)-1,2,4-oxadiazol-5-yl]hexanoic acid (Preparation 94) (110 mg, 0.30 mmol) and N-methylmorpholine (60 μl, 0.54 mmol) in anhydrous tetrahydrofuran (6 ml) was cooled to 0° C., treated with isobutyl chloroformate (42 μl, 0.32 mmol) and stirred under a nitrogen atmosphere for 2.5 hours. O-(Trimethylsilyl)hydroxylamine (120 μl, 1.00 mmol) was added and the mixture was stirred for 18 hours, being allowed to warm to room temperature over this time. The mixture was then treated with methanol and stirred at room temperature for 3 hours. The solvent was removed under reduced pressure. The residue was dissolved in ethyl acetate and washed with water and brine, dried over anhydrous sodium sulphate, filtered and the solvent removed under reduced pressure. The oil was purified by column chromatography on silica gel eluting with a gradient system of 100:0 (dichloromethane:methanol) gradually changing to 90:10 (dichloromethane:methanol) to afford the title compound as a yellow oil (94 mg).

1. stirringthe mixture was stirred for 18 hours
2. stirringstirred at room temperature for 3 hours
3. customThe solvent was removed under reduced pressure
4. dissolutionThe residue was dissolved in ethyl acetate
5. washwashed with water and brine
6. dry with materialdried over anhydrous sodium sulphate
7. filtrationfiltered
8. customthe solvent removed under reduced pressure
9. customThe oil was purified by column chromatography on silica gel eluting with a gradient system of 100:0 (dichloromethane:methanol)

ORD record

ord-8dd82a7747b24f5f93f17eda6ecf5b39

Source dataset

uspto-grants-2002_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06448278B2