Trimethylsilyldiazomethane → 5-Chloro-3-(2-fluoro-4-trimethylsilanyl-phenylamino)-pyrazine-2-carboxylic acid methyl ester

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Reaction Steps

To a solution of 5-chloro-3-(2-fluoro-4-trimethylsilanyl-phenylamino)-pyrazine-2-carboxylic acid (2.95 g, 8.68 mmol) in methanol (50 mL) and toluene (100 mL) at 0° C. under N2 was added a solution of 2M trimethylsilyldiazomethane in hexanes (9.55 mL, 19.0 mmol, 2.2 eq.), and the reaction mixture was stirred at ambient temperature for 30 minutes. The reaction mixture was diluted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium bicarbonate, water and brine, then dried (Na2SO4), filtered and evaporated in vacuo. The resultant residue was purified by column chromotagraphy (Si-PPC, gradient 0 to 50% ethyl acetate in hexane) to give the desired compound as a yellow solid (2.18 g, 71.1%). 1H NMR (CDCl3, 400 MHz) δ ppm 10.54 (s, 1H), 8.36 (t, J=7.86 Hz, 1H), 8.06 (s, 1H), 7.34-7.26 (m, 2H), 4.05 (s, 3H), 0.28 (s, 9H); LCMS (method D1) RT=1.38 min, [M+H]+=354.

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