Triethylamine → 5,6,7,8-Tetrahydroimidazo(1,2-a)pyrazine

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Reaction Steps

A mixture of 2-chloro-4-(3-chloro-4-methoxybenzylamino)-5-ethoxycarbonylpyrimidine (285 mg) obtained in the above (3), 5,6,7,8-tetrahydroimidazo[1,2-a]pyrazine (197 mg), triethylamine (0.22 ml) and chloroform (3 ml) is stirred at room temperature for 2.5 hours, and stirred at 60° C. for 2.5 hours. The reaction mixture is diluted with ethyl acetate, and washed with water. The aqueous layer is extracted with ethyl acetate, and the organic layer is washed with water and a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (silica gel: 10 g, solvent; chloroform:methanol=50:1), and concentrated under reduced pressure. The resultant is triturated with isopropyl ether to give 2-(5,6,7,8-tetrahydroimidazo[1,2-a]pyrazin-7-yl)-4-(3-chloro-4-methoxybenzylamino)-5-ethoxycarbonylpyrimidine (290 mg) as colorless crystalline powder, m.p. 179-182° C., MS (m/z): 443 (MH+).

Provenance & Evidence