Lithium Hexamethyldisilazide → 2-(3,5-Dichloro-pyridin-4-yl)-1-(2,3,4-trimethoxy-phenyl)-ethanone

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Reaction Steps

Methyl 2,3,4-trimethoxybenzoate from preparation 1 (2.7 g, 10 mmol) and 3,5-dichloro-4-methylpyridine (prepared according to literature procedures) was dissolved in dry THF (40 mL). The reaction was cooled on ice and treated dropwise (during 5 minutes) with 1M lithium bis(trimethylsilyl)amide (12 mL, 12 mmol). After 1.5 hours at 0° C. the reaction was quenched with NH4Cl (sat, 100 mL). The organic products were extracted with EtOAc (2×100 mL), and the combined organic phases washed with NaCl (sat, 100 mL). The organic phase was dried over Na2SO4, evaporated in vacuo and purified by flash chromatography using a gradient of EtOAc in heptane as eluent. 2-(3,5-Dichloro-pyridin-4-yl)-1-(2,3,4-trimethoxy-phenyl)-ethanone was obtained as a white solid. 1H NMR (CDCl3) δ=8.43 (2H, s), 7.55 (1H, d), 6.69 (1H, d), 4.61 (2H, s), 4.02 (3H, s), 3.87 (3H, s), 3.84 (3H, s). Yield 2.3 g (65%).

Provenance & Evidence