N-bromobutanimide → ethyl 7-(bromomethyl)-6-chloro-2-(trifluoromethyl)-2H-chromene-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a mixture of the product of Example 157 Step 2 (4.0 g, 12.5 mmol), N-bromosuccinimide (2.3 g, 13.1 mmol), and 21 mL benzene, was added benzoyl peroxide (145 mg. 0.6 mmol). The reaction was heated to 84° C. After 5 h, the reaction was cooled to 25° C. and stored overnight. Solid was removed from the reaction by filtration, and washed with 4 mL benzene. To the filtrate, was added N-bromosuccinimide (1.0 g, 5.7 mmol) and benzoyl peroxide (145 mg, 0.6 mmol). The reaction was heated to 84° C. After 2.5 h, the reaction was cooled to 25° C. The solid was removed from the reaction by filtration and the filtrate was concentrated. The residue was purified by flash chromatography (toluene/EtOAc=9/1) to give 3.9 g a yellow solid of reasonably pure material, which was used without further purification.

Provenance & Evidence