1-Methylpiperazine → 1-(4-Bromo-2-methylbenzoyl)-4-methylpiperazine

Participants

Reaction Steps

4-Bromo-2-methylbenzoic acid (10 g, 46.5 mmol), and HBTU (23 g, 60.5 mmol) were dissolved in DMF (150 mL), then N-methyl piperazine (6.0 g, 60.5 mmol) and DIPEA (21 mL, 121 mmol) were added. The reaction was stirred overnight before the removal of the DMF in vacuo, the gum was quenched with 2.0N NaOH (100 mL), extracted with diethyl ether (3×200 mL), dried (MgSO4) and solvent removed in vacuo to yield a viscous gum. Purification on silica using 0-10% MeOH in DCM as eluent, gave the title compound as viscous oil. The oil was dissolved in the minimum amount of diethyl ether, iso-hexane was added to give a colourless solid which was filtered and dried (11.8 g, 86%); 1H NMR (CDCl3) 7.40 (s, 1H), 7.36 (d, 1H), 7.04 (d, 1H), 3.86-3.79 (m, 2H), 3.27-3.21 (m, 2H), 2.51-2.45 (m, 2H), 2.32-2.29 (m, 8H); MH+ 298.

Provenance & Evidence