1,1'-Carbonyldiimidazole → 4-(12-tert-Butoxycarbonylaminododecanoyl)piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

A mixture of 12-tert-butoxycarbonylaminododecanoic acid (3) (320 mg, 1.01 mmol) and 1,1′-carbonyldiimidazole (181 mg, 1.12 mmol) in anhydrous CH2Cl2 (10 mL) was stirred at room temperature for 2 hours. Then N-tert-butoxycarbonylpiperazine (227.0 mg, 1.22 mmol) was added in one portion and the reaction mixture was stirred at room temperature for 66 hours. After this time, the solvent was removed by rotary evaporation and the resulting residue was purified with Biotage silica gel column chromatography, eluting with 5% to 36% ethyl acetate/hexanes, to afford the desired amide 10 (462.0 mg, 94%) as a white solid: 1H NMR (500 MHz, CDCl3) δ 1.25 (m, 14H), 1.42 (s, 9H), 1.47 (s, 9H), 1.62 (m, 2H), 2.30 (t, 2H), 3.10 (m, 2H), 3.42 (m, 6H), 3.60 (m, 2H), 4.49 (br, 1H). m/z (ESI) 484 [C26H49N3O5+H]+.

Provenance & Evidence