These common heterocyclic compound, 1621-91-6, name is 1H-Pyrazole-3-carboxylic acid, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Recommanded Product: 1621-91-6
Dimethyl sulfate (236 g, 177 mL, 1.87 mol) was added dropwise over 45 min to a stirred solution of pyrazole-3-carboxylic acid (200 g, 1.78 mol) in 20% aqueous sodium hydroxide (850 mL) at 40 C. The reaction mixture was heated at 80 C for 2 h, cooled to room temperature, filtered, the filtrate acidified to pH 1 with concentrated HCI, the precipitate filtered, washed with water, and dried under vacuum to yield 1-methylpyrazole-5-carboxylic acid (85 g, 38%). The filtrate was concentrated in vacuo to 800 ML, extracted with chloroform (15X400 mL), the organic phase dried over anhydrous magnesium sulfate, concentrated in vacuo, and the residue recrystallized from isopropanol to yield 1-METHYLPYRAZOLE-3-CARBOXYLIC acid (74 g) as a white crystalline solid.
The synthetic route of 1H-Pyrazole-3-carboxylic acid has been constantly updated, and we look forward to future research findings.
Reference:
Patent; MERCK & CO., INC.; WO2004/58702; (2004); A2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics