Methyl 1H-indazole-3-carboxylate cas 43120-28-1 reagent use in lab support customized

At 0°C, indazole-3-carboxylic acid (5.0g, 30.8mmol) was dissolved in methanol (50mL), and then 15mL of sulfonyl chloride was slowly added. After the addition was completed, the reaction mixture was heated to reflux and maintained at that temperature for 1.5 hours. After the reaction was completed, the reaction mixture was evaporated under reduced pressure to obtain the crude product. The crude product was then added with saturated sodium bicarbonate solution (50mL) for neutralization, followed by extraction with ethyl acetate (50mL × 3). The organic phases were combined, dried over anhydrous sodium sulfate. The drying agent was filtered out, and the filtrate was evaporated under reduced pressure to obtain 1H-indazole-3-carboxylate methyl ester, which was a white solid (5.1g, yield 94%). The 300MHz, d6-DMSO nuclear magnetic resonance hydrogen spectrum data is as follows: δ13.91 (s, 1H), 8.06 (d, J=8.2Hz, 1H), 7.65 (d, J=8.4Hz, 1H), 7.44 (ddd, J=8.3Hz, 6.9Hz, 1.1Hz, 1H), 7.30 (dd, J=7.9Hz, 6.9Hz, 0.9Hz, 1H), 3.92 (s, 3H).