Tetrahydrofuran → 4-(2,6-Diethyl-4-methylphenyl)-5-hydroxy-2,6-dimethyl-3(2H)-pyridazinone

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Reaction Steps

Under a nitrogen atmosphere, 13 mL of a tetrahydrofuran solution of potassium tert-butoxide (1 mol/L) was stirred at room temperature, to which a solution of 1.9 g of ethyl 2-[2-(2,6-diethyl-4-methylphenylacetyl)-2-methylhydrazono]propanoate (Compound VI-2) in 55 mL of toluene was added dropwise over about 1 hour. The mixture was further stirred at room temperature for 30 minutes. Then, the reaction mixture was concentrated under reduced pressure. To the residue obtained was added 30 mL of ice-water, which was extracted with tert-butyl methyl ether (20 mL×2). To the aqueous layer was then added 1.6 g of 35% hydrochloric acid, which was extracted with ethyl acetate (20 mL×3). The ethyl acetate extracts were combined, washed with saturated sodium chloride aqueous solution (20 mL×2), dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue obtained was subjected to a silica gel column chromatography (ethyl acetate:hexane=1:3 as eluent) to yield 0.76 g of a solid. The solid was washed with cold hexane and air-dried to yield 0.59 g of the title compound as white powder.

Provenance & Evidence