Benzyl chloroformate → HCID 69916010, compound

Participants

Reaction Steps

To a flask containing 1,2,4a,5-tetrahydro-8-nitro-pyrazino[2,1-c][1,4]benzoxazine-3(4H)-carboxylic acid phenylmethyl ester (Step 6, 2.75 g, 7.45 mmol) in tetrahydrofuran (100 mL) and methanol (50 mL) is added 10% palladium on carbon (2.00 g) and ammonium formate (4.69 g, 74.45 mmol), heated to reflux for 2 hours and stirred at ambient temperature for 15 hours. The mixture is filtered through celite and concentrated in vacuo. To the residue dissolved in water (15 mL) and acetone (15 mL) cooled to 0° C. is added potassium carbonate (2.27 g, 16.39 mmol) followed by benzyloxycarbonylchloride (2.34 mL, 16.39 mmol). The reaction is slowly warmed to ambient temperature, stirred for 64 hours, concentrated in vacuo, diluted with ethyl acetate (100 mL), washed with water (2×25 mL) and saline, dried over Na2SO4, concentrated in vacuo and chromatographed on silica gel (230-400 mesh, 200 mL), eluting with hexane/ethyl acetate (75/25). The appropriate fractions are combined (Rf =0.46, TLC, hexane/ethyl acetate, 50/50) and concentrated in vacuo to give the title compound, mp 118-120° C.

Provenance & Evidence