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Yield:-

Reaction Conditions:

Stage #1:NH-pyrazole with sodium hydroxide;hydroxylamine-O-sulfonic acid in water at 0; for 0.5 h;
Stage #2: with sodium periodate in dichloromethane;water at 0; for 12 h;

Steps:

General procedure for syntheses of substrates a
General procedure: Solid hydroxylamine-O-sulfonic acid (15.0 mmol, 1.70 g) was slowly added to a solution of pyrazole (5.0 mmol) in 3.7 M NaOH (25.0 mL), then the reaction system was stirred at 0 °C for 0.5 h. After that, the reaction mixture was extracted three times with CH₂Cl₂. The combined organic layer was washed with saturated brine, dried over with anhydrous Na₂SO₄and concentrated in vacuo.The crude product was dissolved in a mixed solution of CH₂Cl₂(20.0 mL)/H₂O (6.7mL), then NaIO₄ (10.0 mmol, 2.14 g) was slowly added and the reaction system was stirred at 0 °C for 12.0 h. After that, the reaction system was warmed to room temperature. The reaction mixture was extracted three times with CH₂Cl₂, the combined organic layer was washed with saturated brine, dried over with anhydrous Na₂SO₄ and concentrated in vacuo. The crude residue was purified through column chromatography on silica gel with PE/EA as the eluent to afford the desired substrate.

References:

Zhang, Yuan;Luo, Han;Lu, Qixing;An, Qiaoyu;Li, You;Li, Shanshan;Tang, Zongyuan;Li, Baosheng [Chinese Chemical Letters,2021,vol. 32,# 1,p. 393 - 396] Location in patent:supporting information