Acetic Acid → 1-Benzyl 4-tert-butyl 2-methyl piperazine-1,2,4-tricarboxylate

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Reaction Steps

1-Benzyloxycarbonyl-4-tert-butoxycarbonyl-piperazine-2-carboxylic acid (4.76 g, 13.0 mmol) (prepared as described by C. F. Bigge, S. J. Hays, P. M. Novak, J. T. Drummond, G. Johnson, T. P. Bobovski in Tetrahedron Letters, Vol. 30, 5193-5196, 1989) was dissolved in 10% methanol in benzene. A solution of trimethylsilyldiazomethane in hexane (8 mL, 2M) was added dropwise. After 10 min, glacial acetic acid (1 mL) was added. When gas evolution ceased, the solvents were removed in vacuo, and the residue partitioned between ethyl acetate and saturated sodium bicarbonate. The organic phase was washed with saturated brine and dried over magnesium sulfate. The crude product was chromatographed on silica gel with 15% ethyl acetate in hexane, then recrystallized from ethyl acetate/hexane to obtain the title compound as a white powder (1.8 g).

Provenance & Evidence