Benzoyl Peroxide → isopropyl 2-chloro-4-fluoro-5-[5-bromomethyl-3,6-dihydro-3-methyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoate

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Reaction Steps

A solution of 3.5 g of isopropyl 2-chloro-4-fluoro-5-[3,6-dihydro-3,5-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoate in 100 ml of carbon tetrachloride is heated to reflux temperature while stirring for 1 hour with 1.8 g of N-bromosuccinimide and some dibenzoyl peroxide. The reaction mixture is irradiated with a 150 W bulb. The succinimide is filtered off under suction and the filtrate is evaporated to dryness under reduced pressure. The residue is purified by chromatography on a silica gel column using methylene chloride/ethyl acetate (7:1) as the eluent. There is obtained isopropyl 2-chloro-4-fluoro-5-[5-bromomethyl-3,6-dihydro-3-methyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoate, 1H--NMR (CDCl3, 400 MHz) 7.84 ppm. (d, 1H), 7.58 ppm (s, 1H), 7.36 ppm (d, 1H), 5.24 ppm (m, 1H), 4.35 ppm (d, 1H), 4.29 ppm (d, 1H), 3.48 ppm (s, 3H), 1.37 ppm (2d, 6H).

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