Acetic Anhydride → trans-3-(3-Cyclopentoxy-4-methoxyphenyl)-4-methoxycarbonyl-1-(methylcarbonyl)pyrrolidine

Participants

Reaction Steps

To a solution of trans-3-(3-cyclopentoxy-4-methoxyphenyl)-4-(methoxycarbonyl)pyrrolidine (605 mg, 1.89 mmol) in 5 mL of CH2Cl2 was added 4-dimethylaminopyridine (347 mg, 2.84 mmol), followed by 1 mL of acetic anhydride After 12 hr the reaction was diluted with CH2Cl2 and washed with 1M H3PO4. The organic layer was dried over MgSO4, filtered, and concentrated under reduced pressure. Silica gel chromatography (2:1, hexanes:ethyl acetate) provided trans-3-(3-cyclopentoxy-4-methoxyphenyl)-4-methoxycarbonyl-1-(methylcarbonyl)pyrrolidine as a viscous oil (370 mg, 54%). 1H-NMR (300 MHz) analysis indicates a 1:1 mixture of amide rotamers (δ 2.07 and 2.09 singlets). Anal. Calcd for C20H27NO5 : C, 66.46; H, 7.53; N, 3.88. Found: C, 66.19; H, 7.58; N, 3.82.

Provenance & Evidence