Reacción #1178426

Ecuación de reacción

Hydroxybenzotriazole

benzoic acid

DIC

→

benzoic acid benzotriazol-1-yl ester

Disolventes

DMF CH2Cl2

Condiciones de reacción

Tratamiento posterior

1. 1
   FiltraciónThe mixture was filtered
2. 2
   Lavadothe resin was washed with DMF (10×5 mL) and CH2Cl2 (10×5 mL)

Procedimiento

Hydroxybenzotriazole resin (0.107 g, 0.196 mmol) was treated with benzoic acid (0.12 g, 0.982 mmol, 5 eq), DIC (0.152 mL, 0.982 mmol, 5 eq) and DMAP (0.024 g, 0.196 mmol, 1 eq) in DMF-CH2Cl2 (1:1) and shaken for 5 h. The mixture was filtered and the resin was washed with DMF (10×5 mL) and CH2Cl2 (10×5 mL) to give resin-supported benzoic acid benzotriazol-1-yl ester. To a suspension of the resin-ester (0.196 mmol, 1.5 eq) in CH2Cl2 (2 mL) were added i-Pr2NEt (0.033 mL, 0.196 mmol, 1.5 eq) and 2-amino-2-methyl-pentan-3-one (0.03 g, 0.131 mmol, 1 eq). The mixture was agitated for 16 h and filtered. The filtrate was shaken with a weakly basic ion exchange resin Amberlite IRA-95 (1 g, 4.7 mmol g−1, 25 eq) for 16 h to remove benzoic acid present in the solution and filtered. The filtrate was eluted through a short column of silica gel (hexane/ethyl acetate 50:50) to remove the unreacted amine. The organic solvent was evaporated to leave N-(1,1-dimethyl-2-oxo-butyl)-benzamide (0.03 g, 87%) as a white solid. 1H NMR (200 MHz, CDCl3) δ (ppm): 1.14 (t, J=7.2 Hz, 3H), 1.57 (s, 6H), 2.63 (q, J=7 Hz, 2H), 7.21 (bs, 1H), 7.38-7.56 (aromatic H's, 3H), 7.79 (dd, J=8, 1.8 Hz, 2H). MS (ESI, positive ion): m/z 220.2 (M+1)+.

Fuente