Triethylamine → 6-Chloro-2-[[4-[5-(trifluoromethyl)pyridin-2-yl]-1-piperazinyl]methyl]imidazo[1,2-a]pyridine

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Reaction Steps

A mixture of 1-(5-trifluoromethylpyridin-2-yl)piperazine (0.4803 g), 6-chloro-2-(chloromethyl) imidazo[1,2-a]pyridine (Example 4, Step 1; 0.4177 g), triethylamine (0.231 g), and ethylene glycol (1 mL) is stirred at 80° C. for 70 min. after which additional 6-chloro-2-(chloromethyl)imidazo[1,2-a]pyridine (0.072 g) is added; thirty minutes later another portion (0.0517 g) is added. After stirring for a total of 2 h, the mixture is cooled and partitioned between dichloromethane and aq. sodium bicarbonate. The organic layers are dried over sodium sulfate and concentrated. Chromatography on silica gel using methanol/dichloromethane (4/96) and crystallization from ethyl ether/hexane gives 0.549 g of the title compound; mp 81-82° C.; MS m/z 395; IR (mineral oil) 1617, 1332, 1328, 1112, 1082 cm-1. 1H NMR (CDCl3) δ2.68, 3.69, 3.77, 6.62, 7.14, 7.52, 7.55, 7.61, 8.14, 8.38.

Provenance & Evidence