Ethyl chloronicotinate → HCID 10654983, compound

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Reaction Steps

Sodium methoxide (18 mL, 25 wt % in methanol) was added slowly to a solution of ethyl-2-chloronicotinate (11.134 g 60 mmol) in 60 mL anhydrous methanol. The reaction mixture was stirred under reflux for 15 h, then cooled to rt. Methanol was removed in vacuo. The residue was dissolved in EtOAc (200 mL) and saturated aqueous ammonium chloride (50 mL) was added. The organic layer was separated and dried over anhydrous Na2SO4. The solvent was removed to give ethyl-2-methoxynicotinate (8.58 g, 79%). Sodium hydride (60% in mineral oil, 0.48 g, 12 mmol) was dissolved in anhydrous DMF (10 mL). A solution of 3′-chloro-4′-methoxy acetophenone (1.85 g, 10 mmol) in anhydrous DMF (5 mL) was added drop-wise at 0° C. under nitrogen. The mixture was stirred at 0° C. for 5 min. and then at rt for 30 min. The mixture was cooled to 0° C. A solution of ethyl 2-methoxy nicotinate (1.81 g, 10 mmol) in anhydrous DMF (5 mL) was added slowly. The ice bath was removed and the mixture was stirring at rt under nitrogen for 20 h. Water (20 mL) was added and the mixture was extracted with EtOAc (2×100 mL). The combined organic layers were washed with brine and dried over anhydrous Na2SO4. Removal of solvent gave a dark colored solid. Triturating with ether gave a yellow solid (1.64 g, 51%). The yellow solid (1.36 g, 4.21 mmol) and pyridinium hydrochloride (7.3 g, 63.2 mmol) were mixed together and stirred at 190° C. for 2 h, then cooled to rt. Water (100 mL) was added. The solid was separated by filtration, washed with water and dried under vacuum. The crude compound was purified by column chromatography (Silica Gel 230-400 mesh; 5% methanol in dichloromethane as an eluent to afford 2-(3-chloro-4-hydroxyphenyl)-4H-pyrano[2,3-b]pyridine-4-one (0.385 g, 33% yield) as yellow solid. MS (ES) m/z: 275.94+273.92 (two isotopes of M); Mp. 259-262° C.

Provenance & Evidence