N-bromobutanimide → 8-Chloro-3-(2-chloro-5-fluoropyrimidin-4-yl)imidazo[1,2-a]pyridine

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Reaction Steps

25.2 g of the compound [67-1] was dissolved in a mixed solvent of 320 mL of 1,4-dioxane and 32 mL of water. Then, 22.2 g of N-bromosuccinic acid imide was added under an ice-cold condition, and the mixture was stirred at room temperature for 2 hours. To the reaction solution, 16.0 g of 2-amino-3-chloropyridine was added, and the mixture was stirred overnight at room temperature. A saturated aqueous sodium hydrogen carbonate solution was added thereto, and the mixture was extracted with a mixed solvent of chloroform and methanol (mixing ratio: 9/1). The obtained organic layer was dried over anhydrous sodium sulfate. The insolubles were filtered, and the filtrate was concentrated under reduced pressure. To the obtained residue, hexane was added, and the mixture was stirred for 30 minutes. The solid was taken by filtration, and dried under reduced pressure to obtain 20.0 g of 8-chloro-3-(2-chloro-5-fluoropyrimidin-4-yl)imidazo[1,2-a]pyridine [67-2] (hereinafter, referred to as the compound [67-2]) as a yellow solid.

Provenance & Evidence