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ChemicalBook CAS DataBase List Pyrido[2,3-b]pyrazine, 7-methyl- (9CI)
397325-35-8

Pyrido[2,3-b]pyrazine, 7-methyl- (9CI) synthesis

1synthesis methods
-

Yield:397325-35-8 60%

Reaction Conditions:

with caesium carbonate;triphenylphosphine in 1,4-dioxane;

Steps:

105 Example 105

Example 105 Under nitrogen atmosphere, to a mixture of 7-bromopyrido[2,3-b]pyrazine (300 mg), methyl boronate (100 mg) and cesium carbonate (930 mg) were added dioxane (7.0 ml), bis(dibenzilidenacetone)-palladium (80.0 mg) and triphenylphosphine (87.0 mg), and the mixture was stirred at 100° C. for 2.5 hours. To the reaction solution was added a saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted three times with ethyl acetate. The extracts were combined, washed with a saturated brine, dried over magnesium sulfate, and filtered. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column (hexane/ethyl acetate=3/1→1/1→0/1→ethyl acetate/ethanol=10/1) to give 7-methyl-pyrido[2,3-b]pyrazine (125 mg, 60%). 1H NMR (CDCl3, 400 MHz) δ 9.06 (d, 1H, J=2.3 Hz), 9.02 (d, 1H, J=1.7 Hz), 8.91 (d, 1H, J=1.7 Hz), 8.24 (d, 1H, J=2.3 Hz), 2.65 (s, 3H).

References:

US2003/181496,2003,A1

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