C(OCCCC)CCC.[C:10]1([Li])[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.C(OCC)C.[CH3:22][C:23]1[C:28]([C:29]2[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=2)=[N:27][CH:26]=[CH:25][N:24]=1>O>[CH3:22][C:23]1[C:28]([C:29]2[CH:30]=[CH:31][CH:32]=[CH:33][CH:34]=2)=[N:27][CH:26]=[C:25]([C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)[N:24]=1In a nitrogen atmosphere, 10 mL of a dibutyl ether solution containing phenyl lithium (produced by Wako Pure Chemical Industries, Ltd., 2.1 mol/L) and 120 mL of diethylether were mixed. While the mixed solution was being cooled with ice, 2.87 g of 2-methyl-3-phenylpyrazine was added thereto and stirred at a room temperature for 24 hours. Water was added into this mixture, and an organic layer was extracted with ethyl acetate. The organic layer obtained was dried with magnesium sulfate. The solution after drying was added with activated manganese dioxide excessively and filtration was conducted. A solvent of the obtained filtrate was distilled off, so that a residue was obtained. This residue was purified by silica gel column chromatography which uses dichloromethane as a developing solvent; thereby obtaining an objective pyrazine derivative Hmppr-P (orange oily substance, yield of 12%). A synthetic scheme of Step 1 is shown in the following (a-5).
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