Tetra-n-butylammonium tribromide → HCID 86727364, compound

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Reaction Steps

To a solution of 4-(4-methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-yl)-piperidine-1-carboxylic acid tert-butyl ester (Example #71, Step B, 0.50 g, 1.249 mmol) in DCM (5 mL) and MeOH (5 mL) was added tetrabutylammonium tribromide (0.662 g, 1.373 mmol) in portions and the mixture was stirred for 30 min at ambient temperature. The reaction was quenched by addition of saturated aqueous Na2S2O3 solution (5 mL) and the pH was adjusted to 7 with saturated aqueous NaHCO3 solution. The mixture was extracted with DCM (3×20 mL). The combined organic phase was washed with brine (20 mL), dried over anhydrous Na2SO4, filtered and concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 20% EtOAc in petroleum ether) to give 4-(7-bromo-4-methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-yl)-piperidine-1-carboxylic acid tert-butyl ester (0.34 g, 57%). LC/MS (Table 1, Method 2) Rt=1.289 min.; MS m/z: 479/481 [M+H]+.

Provenance & Evidence