Lithium Hexamethyldisilazide → 1-(1-Ethyl-propyl)-7-methyl-5-(2,4,6-trimethyl-phenoxy)-1,4-dihydro-2H-pyrido[3,4-b]pyrazin-3-one

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Reaction Steps

To a solution of 2-chloro-N-[4-(1-ethyl-propylamino)-6-methyl-2-(2,4,6-trimethyl-phenoxy)-pyridin-3-yl]-acetamide (170 mg, 0.42 mml) in 2 ml of dry THF was added a solution of 1 M lithium bis(trimethylsilyl)amide in THF (0.84 ml, 0.84 mmol) at −78° C. The mixture was gradually warmed to room temperature and stirred at room temperature for 2 hours. An additional 0.42 ml of 1M lithium bis(trimethylsilyl)amide in HF was added at −78° C. and the resulting mixture was stirred at room temperature overnight. The mixture was quenched with water and extracted with ethyl acetate. The organic layer was dried and concentrated to dryness to give 160 mg of yellow solid. The solid residue was purified through silica gel column chromatography using 15% ethyl acetate (EtOAc) in hexane as eluent to give 91 mg (59%) of the title compound as white crystals. 1H NMR (CDCl3) δ 7.84 (s, 1H), 6.88 (s,2H), 6.22 (s,1H), 3.82(s,2H), 3.58(m,1H), 2.30(s,3H), 2.18(s,3H), 2.08(s,6H), 1.63(m,4H), 0.95(m,6H) ppm.

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