1,1'-Carbonyldiimidazole → tert-butyl (3R)-6-cyclohexyl-3-[3-(2-methoxyethyl)-1,2,4-oxadiazol-5-yl]hexanoate

Participants

Reaction Steps

A solution of (2R)-2-[2-(tert-butoxy)-2-oxoethyl]-5-cyclohexylpentanoic acid (Preparation 1) (500 mg, 1.70 mmol) in dichloromethane (30 ml) was treated with 1,1′-carbonyidiimidazole (272 mg, 1.70 mmol) and the solution was stirred at room temperature for 1 hour. N′-hydroxy-3-methoxypropanimidamide (J.Amer.Chem.Soc.; 80; 1958; 3769-3771) (201 mg, 1.70 mmol) was then added and the mixture was stirred for 1 hour. The solvent was removed under reduced pressure and the residue was heated neat at 120° C. under a nitrogen atmosphere for 2 hours. The crude product was then purified by column chromatography on silica gel eluting with dichloromethane:methanol (99:1) to afford the title compound as a colourless oil (410 mg).

Provenance & Evidence