3-Hydroxypyridine → 2-[(Pyridin-3-yloxy)methyl]-2,3-dihydronaphtho[1,2-b][1,4]oxathiine-5,6-dione

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Reaction Steps

To a solution of 2-(hydroxymethyl)-2,3-dihydronaphtho[1,2-b][1,4]oxathiine-5,6-dione (0.35 g, 1.34 mmol) in tetrahydrofuran (10.0 mL) was added triphenylphosphine (1.4 g, 5.34 mmol) and pyridin-3-ol (0.507 g, 5.34 mmol) followed by diethyl (Z)-diazene-1,2-dicarboxylate (0.53 mL, 3.34 mmol). The reaction mixture was stirred at room temperature for 8 hours. The reaction was quenched by addition of water (30 mL). The aqueous layer was extracted with dichloromethane (2×20 mL). The organic extracts were combined and extracted thrice with 1.0N HCl (10 mL). The HCl extracts were combined and its pH adjusted to 9 with a saturated sodium carbonate solution. The aqueous layer was extracted with dichloromethane (2×20 mL), extracts combined, dried with sodium sulfate and concentrated under reduced pressure. The crude mixture was purified by flash column chromatography (SiO2, 50% EtOAc in hexanes to 80% EtOAc in hexanes) to give the product as a purple solid (0.065 g, 14%). M.p.=153-155° C.; 400 MHz 1H NMR (CDCl3) δ: 8.43-8.35 (m, 1H), 8.33-8.24 (m, 1H), 8.05-7.94 (m, 1H), 7.72-7.56 (m, 2H), 7.56-7.4 (m, 2H), 7.33-7.2 (m, 1H), 4.98-4.86 (m, 1H), 4.54-4.34 (m, 2H), 3.34-3.16 (m, 2H); LCMS: 340 [M+H].

Provenance & Evidence