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

Participants

Reaction Steps

A solution of 0.850 ml (10 mmol) oxalyl chloride in 20 ml CH2Cl2 is added dropwise to a iced-cooled solution of 1.10 g (5 mmol) 4-bromo-2-methylbenzoic acid in 30 ml CH2Cl2. After complete addition, the cooling bath is removed and stirring maintained for 1 h at RT. The solvent is evaporated to dryness, the resultant colorless residue is dried under vacuum and then diluted with 25 ml CH2Cl2. This solution is then added dropwise to a mixture of 1.01 g (10 mmol) of N-methylpiperazine in 25 ml CH2Cl2. After 1 h 30, the reaction mixture is diluted with water and the two phases are separated. The aqueous phase is re-extracted with CH2Cl2 and the combined organic extracts are successively washed with a sat.solution of NaHCO3, water, sat. brine, dried over Na2SO4, filtered and the filtrate is concentrated in vacuo to afford, after drying in HV, the title compound which is used in the next step without further purification.

Provenance & Evidence