Potassium Iodide → 4-Benzhydrylpiperazin-2-one

Participants

Reaction Steps

tert-Butyl 3-oxopiperazine-1-carboxylate (0.6 g, 3 mmol) in methylene chloride (10 mL) was treated with trifluoroacetic acid (3 mL) at room temperature for 1 hour. The reaction mixture was concentrated and the obtained trifluoroacetic salt of 2-piperazinone was used without purification. To a piperazin-2-one 2,2,2-trifluoroacetate (0.4 g, 1.87 mmol) solution in N,N-dimethylformamide (3 mL) was added bromodiphenylmethane (0.45 g, 1.87 mmol), potassium carbonate (0.78 g, 5.7 mmol) and catalytic amount of potassium iodide and the reaction mixture was stirred at ambient temperature overnight. Then it was evaporated, partitioned in H2O/methylene chloride. The organic layer was dried over MgSO4, evaporated in vacuo and chromatographed on silica gel eluting with 30% ethyl acetate/hexane and then with 10% methanol/dichloromethane/1% ammonium hydroxide to yield the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 7.80 (s, 1H), 7.46 (m, 4H), 7.31 (m, 4H), 7.21 (m, 2H), 4.37 (s, 1H), 3.17 (m, 2H), 2.79 (s, 2H); MS/DCI 267 (M+H)+.

Provenance & Evidence