2-Chloroethyl chloroformate → 8-[2-(2-Chloroethoxycarbonylamino)-6-methylbenzylamino]-2,3-dimethylimidazo[1,2-a]pyridine

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Reaction Steps

2-Chloroethyl chloroformate (12.4 g, 81 mmol) dissolved in dichloromethane (40 ml) is added dropwise at RT, during the course of about 30 min, to a solution of 8-(2-amino-6-methylbenzylamino)-2,3-dimethylimidazo[1,2-a]pyridine (19.65 g, 70 mmol) in anhydrous dichloromethane (600 ml). The mixture is then stirred at RT for 16 h and then extracted with sodium hydrogen carbonate (4×200 ml). After extraction of the aqueous phases with dichloromethane (200 ml), the combined organic extracts are washed with water (2×200 ml), dried over magnesium sulfate and concentrated. The crude product which remains (33.9 g) is used directly for the further reaction in Example 1b.

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