Synthetic Route of 1453-58-3, A common heterocyclic compound, 1453-58-3, name is 3-Methylpyrazole, molecular formula is C4H6N2, 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.
A suspension of hexane washed potassium hydride (0.424 g) in dimethylformamide (5 ml) was treated in one portion with 3-methyl pyrazole (0.85 ml) while stirring. After the gas evolution ceased, 2-chloro-4-fluorobenzoic acid methyl ester (2.0 g, 10.6) was added to the clear solution and heated at 130° C. for 15 minutes. The reaction mixture was cooled to room temperature and partitioned between ethyl acetate and brine. The organic phase was washed with water, brine,. and dried over anhydrous sodium sulfate. Removal of solvent in vacuo afforded 2.2 g of a yellow oil. (Note: 20percent hydrolysis of the ester was detected by analysis of the NMR spectrum of the crude product). The desired regioisomer 2-chloro-4-(3-methyl-1H-pyrazol-1-yl)-benzoic acid methyl ester was isolated from the other isomer (described below) by flash column chromatography on silica gel (Merck 60) eluting with dichloromethane-hexane 2:1) to give 1.55 g of the title compound as a colorless solid. MS (EI m/z: 250/252 (M)+. [00283] The 5-regioisomer, namely 2-chloro-4-(5-methyl-1H-pyrazol-1-yl)-benzoic acid methyl ester was isolated from the above flash column chromatography on silica gel (Merck 60) by further eluting with dichloromethane-hexane 2:1 to give 0.20 g of the product as a colorless solid. MS (EI), m/z: 250/252 (M)+.
The synthetic route of 1453-58-3 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; American Cyanamid Company; US6831079; (2004); B1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics