In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 25016-17-5, name is Methyl 5-methyl-1H-pyrazole-3-carboxylate belongs to pyrazoles-derivatives compound, it is a common compound, a new synthetic route is introduced below. category: pyrazoles-derivatives
b. Synthesis of I.S-dimethyl-pyrazole-delta-carboxylic acid methylester; S-methyl-pyrazole-delta-carboxylic acid methyl ester (6.8 Kg Kg) is dissolved in DMF (8L) and dimethyl sulfate (6.0 L) is added dropwise in over three hours. The reaction is exothermic and the addition of dimethyl sulfate must be controlled so that the internal temperature does not exceed 900C. After complete addition, the mixture is heated for 18 hours at 800C. The mixture is then cooled to room temperature, diluted with ice (3.4 Kg), and cooled in an ice bath. A solution of aqueous 28% ammonium hydroxide (8.6 L) is added to the reaction mixture over 3 hours. The resulting mixture is stirred for 18 hours, diluted with ethyl acetate (12 L) and water (16 L), extracted, and the layers are separated. The organic layer is washed with water (4L), dried over MgSO4, filtered, and concentrated under reduced pressure to provide 5.14 Kg of 1 ,3-dimethyl-pyrazole-delta-carboxylic acid methylester (69 % yield with a purity of >90 % by HPLC). The crude product is used directly in the next step.
The synthetic route of 25016-17-5 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; PFIZER INC.; WO2006/48761; (2006); A2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics