Hydrochloric Acid → 5-Hydroxy-4-methoxy-2-nitrobenzaldehyde

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Reaction Steps

3-Hydroxy-4-methoxybenzaldehyde (15.2 g, 0.1 mol) obtained in the same manner as in Reference Example 3 was dissolved in THF (150 ml), to which sodium nitrate (8.5 g, 0.1 mol) and lanthanum nitrate hexahydrate (8.7 g, 0.2 mol) were added, and then a mixture of concentrated hydrochloric acid and water at a ratio of 1:1 (70 ml) was added dropwise over a period of 20 minutes. The mixture was stirred for 40 minutes at room temperature, and the separated organic layer was successively washed with water (50 ml), a saturated aqueous solution of sodium hydrogencarbonate (50 ml), and a saturated aqueous solution of sodium chloride (100 ml), dried over anhydrous magnesium sulfate, filtered to remove the desiccating agent, and concentrated under reduced pressure to give a mixture of the title compounds 4a and 4b as pale red crystals (4a:4b=1:1, 13.3 g, yield 67.5%) (Table 2).

Provenance & Evidence