Potassium Carbonate → 3-(5-Ethynyl-1,3,4-oxadiazol-2-yl)-5-(4-isopropylsulfonylphenyl)pyrazin-2-amine

関与物質

反応手順

Dibromo(triphenyl)phosphorane (1.208 g, 2.862 mmol) was added to a suspension of 3-trimethylsilylprop-2-ynoic acid (84.8 mg, 0.60 mmol) and 3-amino-6-(4-(isopropylsulfonyl)phenyl)pyrazine-2-carbohydrazide (200 mg, 0.60 mmol) in acetonitrile (3.000 mL) at room temperature and the resulting solution stirred for 30 min. DIPEA (385.4 mg, 519.4 μL, 2.982 mmol) was then added and a precipitate quickly formed. The resulting mixture was stirred at room temperature for 1 h and was then filtered. The reaction mixture was concentrated in vacuo and the residue taken up in methanol (5 mL) and potassium carbonate (131.9 mg, 0.9541 mmol) added and the resulting solution stirred at room temperature overnight. The reaction mixture was diluted with ethyl acetate (5 mL) and water (5 mL) and the layers separated. The aqueous layer was extracted further with ethyl acetate (2×5 mL), dried over MgSO4 and concentrated in vacuo. The material was purified by reverse phase preparative HPLC [Waters Sunfire C18, 10 μM, 100 Å column, gradient 10%-95% B (solvent A: 0.05% TFA in water; solvent B: CH3 CN) over 16 minutes at 25 mL/min]. Product fractions were freeze dried to leave the product as a yellow solid (56.1 mg, 27% yield); 1H NMR (400 MHz, DMSO) d 1.18 (m, 6H), 3.44 (m, 1H), 5.48 (s, 1H), 7.96 (m, 2H), 8.32 (m, 2H) and 9.08 (s, 1H) ppm; MS (ES+) 370.14

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