Diisopropylethylamine → (R)-6-cyclohexyl-N-hydroxy-3-(3-(pyrrolidine-1-carbonyl)-1,2,4-oxadiazol-5-yl)hexanamide

A solution of (3R)-6-cyclohexyl-3-[3-(1-pyrrolidinylcarbonyl)-1,2,4-oxadiazol-5-yl]hexanoic acid (Preparation 13) (288 mg, 0.79 mmol) and N,N-diisopropylethylamine (138 μl, 0.79 mmol) in N,N-dimethylformamide (6 ml) was treated with O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (452 mg, 1.19 mmol) and the resulting mixture was stirred at room temperature under a nitrogen atmosphere for 1 hour. Further N,N-diisopropylethylamine (552 μl, 3.16 mmol) was then added, followed by the hydroxylamine hydrochloride (165 mg, 2.38 mmol) and the mixture stirred at room temperature for 18 hours. The solvent was removed under reduced pressure and the residue wasa partitioned between ethyl acetate and pH 7 aqueous buffer. The organic layer was separated, washed sequentially with water and brine, dried over anhydrous magnesium sulphate, filtered and the solvent removed under reduced pressure. The residue was purified by column chromatography on silica gel eluting with dichloromethane:methanol (98:2) to afford the title compound as a foam (126 mg).

1. stirringthe mixture stirred at room temperature for 18 hours
2. customThe solvent was removed under reduced pressure
3. customthe residue wasa partitioned between ethyl acetate and pH 7 aqueous buffer
4. customThe organic layer was separated
5. washwashed sequentially with water and brine
6. dry with materialdried over anhydrous magnesium sulphate
7. filtrationfiltered
8. customthe solvent removed under reduced pressure
9. customThe residue was purified by column chromatography on silica gel eluting with dichloromethane:methanol (98:2)

ORD record

ord-938c18c6012d4a62941d231892ed97d5

Source dataset

uspto-grants-2005_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06897306B2