Bromine → 9-bromo-4-oxo-2-pyrimidin-4-yl-5,6,8,9-tetrahydro-4H-1,4-a,7-triaza-benzocycloheptene-7-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 4.5 g (14.27 mmol) of 4-oxo-2-pyrimidin-4-yl-5,6,8,9-tetrahydro-4H-1,4a,7-triaza-benzocycloheptene-7-carboxylic acid ethyl ester in dry tetrahydrofuran (140 mL) under argon at −30° C. was added 15.70 mL (15.70 mmol) of lithium bis(trimethylsilyl)amide (1M in tetrahydrofuran). The solution was stirred at −30° C. for 5 min and 0.77 mL (14.98 mmol) of bromine was added. The reaction was stirred at −30° C. to room temperature during 3 hours. The mixture was quenched with the addition of a saturated solution of ammonium chloride and extracted with ethyl acetate. The organic phase was dried over sodium sulfate and concentrated. The residue was purified by flash chromatography (dichloromethane with 1 to 3% of methanol) to afford 2.6 g (46%) of product.

Provenance & Evidence