Reaction #1552053

Reaction equation

2-methyl-3-phenylpyrazine

dibutyl ether

phenyl lithium

diethylether

→

pyrazine

Yield 12.0%

3-methyl-2,5-diphenylpyrazine

Yield 12.0%

Solvents

Water

Conditions

Workup

1. 1
   workup.ADDITIONwere mixed
2. 2
   workup.ADDITIONwas added
3. 3
   Extractionan organic layer was extracted with ethyl acetate
4. 4
   OtherThe organic layer obtained
5. 5
   Dryingwas dried with magnesium sulfate
6. 6
   OtherThe solution after drying
7. 7
   workup.ADDITIONwas added with activated manganese dioxide excessively and filtration
8. 8
   workup.DISTILLATIONA solvent of the obtained filtrate was distilled off, so that a residue
9. 9
   Otherwas obtained
10. 10
    OtherThis residue was purified by silica gel column chromatography which

Procedure

In 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).

Source