2,3-Dihydro[1,4]dioxino[2,3-c]pyridine-7-carbaldehyde → 2,3-Dihydro[1,4]dioxino[2,3-c]pyridine-7-carboxylic acid

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Reaction Steps

To a solution of 2,3-dihydro-[1,4]dioxino[2,3-c]pyridine-7-carbaldehyde (722 mg, 4.37 mmol) in 2-methyl-2-propanol (95 mL) and 2-methyl-2-butene (22 mL) was added dropwise a solution of sodium chlorite (80%, 4.55 g, 40.22 mmol) and sodium dihydrogenphosphate (3.65 g, 26.45 mmol) in water (35 mL). The resulting solution was stirred at rt for 19 h. The volatiles were removed under reduced pressure. The residue was diluted with water (20 mL) and pH was adjusted to 3 by addition of 1N HCl. The aq. layer was extracted with DCM-MeOH 9-1 (25×30 mL). The combined extracts were dried over Na2SO4, filtered and evaporated under reduced pressure. The residue was triturated in ether and filtered to give the title acid as a white solid (0.405 g, 51% yield).

Provenance & Evidence