Methanol → Methyl 2-(piperazin-1-yl)benzoate

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Reaction Steps

2-Piperazin-1-yl-benzoic acid (1.000 g, 4.89 mmol) is suspended in 10 mL of MeOH. To this is added 5 mL of conc. H2SO4. The mixture is stirred for 16 h resulting in a white precipitate. An additional 5 mL of H2SO4 is added with an additional 10 mL of MeOH. The reaction volume is increased by an additional 200 mL of MeOH and 60 mL of H2SO4 and the mixture is stirred an additional 2 h and then heated at reflux for 12 h. The reaction volume is then reduced to approximately 175 mL and applied to an ion exchange column, eluting with 5×200 mL of 10% NH3/MeOH and then the product fractions are concentrated. The eluent is co-evaporated with toluene to remove residual water to give 0.667 g of 2-piperazin-1-yl-benzoic acid methyl ester in 63% yield.

Provenance & Evidence