Hydrogen Peroxide → (1s,2s,5e)-5-Benzylidene-2-[(4-phenylpiperazin-1-yl)carbonyl]cyclohexanecarboxylic acid

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Reaction Steps

To a stirred solution of methyl(1S,2S,5E)-5-benzylidene-2-[(4-phenylpiperazin-1-yl)carbonyl]cyclohexanecarboxylate (116 mg, 0.000277 mol) in tetrahydrofuran (6.0 mL, 0.074 mol) at rt was added a solution of lithium hydroxide (102 mg, 0.00416 mol) in water (2.0 mL, 0.11 mol). The resulting cloudy solution was stirred at rt for 17 h. LCMS showed that there was only 40% conversion. The reaction mixture was cooled to 0° C., hydrogen peroxide (0.113 mL, 0.00111 mol) was then added. The reaction mixture was stirred at 0° C. for 2 h. LCMS showed that there was little change. The reaction mixture was then stirred at rt over the weekend. LCMS showed the reaction was done. The reaction was quenched with 10% Na2S2O3 (10 mL), acidified with 1 N HCl (5 mL) to pH=4, extracted with EtOAc (2×). The combined organic layers were washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give the desired product as a colorless solid. (112 mg, 100% in yield). MS (ESI): (M+H)+=405.1.

Provenance & Evidence