Hydrochloric Acid → HCID 178464510, 화합물

참여 물질

반응 단계

N,N-Diethyl-3-hydroxy-4-amino-1-naphthalenesulfonamide (2.94 g) was dissolved in 10 ml of ethanol and 10 g of ice was added. The reaction mixture was cooled in an ice bath to keep the temperature below 5° C. Hydrochloric acid (3 ml, 37% ) was added, followed by dropwise addition of a solution of 0.83 g sodium nitrite in 2 ml water and stirring was continued for 30 minutes. In a separate flask, to a solution of 1.26 g 2,4-dihydro- 2-ethyl-5-methyl-3H-pyrazol-3-one in 10 ml ethanol was added 11 ml of 20% aqueous sodium acetate followed by 9 ml of 10% aqueous sodium hydroxide, while the temperature was maintained below 5° C. The diazonium salt (as a suspension) was then added portionwise to the stirred solution of 2-dihydro-2-ethyl-5-methyl-3H-pyrazol-3-one at 5° C. and the resulting mixture stirred for 30 min at room temperature. The product was extracted with 100 ml chloroform, the organic layer was washed with 5% formic acid and water, and dried over anhydrous sodium sulfate; and the solvent evaporated to give crude 3.25 g N,N-diethyl-3-hydroxy-4-(5-hydroxy-3-methyl-1-ethyl-1H-pyrazol-4-yl)azo-1-naphthalenesulfonamide. The product was subjected to column chromatography (toluene) to give pure 2.55 g N,N-diethyl-3-hydroxy-4-(5-hydroxy-3-methyl-1-ethyl-1H-pyrazol-4-yl)azo-1-naphthalenesulfon amide which was crystallized from methanol to give dark red prisms, m.p. 174° -175° C.

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