Mefenpyr-diethyl synthesis
- Product Name:Mefenpyr-diethyl
- CAS Number:135590-91-9
- Molecular formula:C16H18Cl2N2O4
- Molecular Weight:373.23
97-63-2
![ethyl chloro[(2,4-dichlorophenyl)hydrazono]acetate](/CAS/20180711/GIF/27143-12-0.gif)
27143-12-0
135590-91-9
The general procedure for the synthesis of diethyl 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylate from ethyl methacrylate and ethyl 2-chloro-2-(2-(2,4-dichlorophenyl)hydrazinylidene)acetate was as follows: 22.8 g of ethyl methacrylate and 14.8 g of 2-chloro-2-(2-(2,4-dichlorophenyl) hydrazinyl) ethyl acetate were mixed and heated to 50-60 °C. Over 30 minutes, 7.6 g of triethylamine was slowly added dropwise to the reaction mixture. Subsequently, the reaction temperature was raised to 70 °C and the reaction was continued with stirring for 2 hours. After completion of the reaction, the reaction mixture was allowed to cool to room temperature and the precipitate was isolated by filtration. The filtrate was carefully concentrated under reduced pressure to afford 18.1 g of the target product 1-(2,4-dichlorophenyl)-5-methyl-4,5-dihydro-1H-pyrazole-3,5-dicarboxylic acid diethyl ester.
![Acetic acid, 2-[2-(2,4-dichlorophenyl)hydrazinylidene]-, ethyl ester](/CAS/20210305/GIF/1016169-48-4.gif)
Yield:135590-91-9 78%
Reaction Conditions:
with tert.-butylhydroperoxide;iodine in water;N,N-dimethyl-formamide at 80; for 4 h;Temperature;Reagent/catalyst;Solvent;
Steps:
3-10 synthesis of mefenpyr
ethyl 2-[2-(2,4-dichlorophenyl)hydrazin-1-ylidene]acetate (13.0 g, 0.05 mol) and ethyl methacrylate (6.8 g, 0.06 mol) were added to a 250 mL eggplant bottle. Add DMF (80 mL) to dissolve and dissolve, then add molecular iodine (12.6 g, 0.05 mol) and 70% aqueous solution of TBHP (12.8 g, 0.1 mol) to the reaction system, react at 80 ° C for 4 h, complete the reaction, add 100 ml of 10% aqueous sodium hydrogen sulfite solution. It was extracted with ethyl acetate (100 mL × 3), and the ethyl acetate layer was washed with brine (100 mL × 2)The petroleum ether was recrystallized to obtain 14.5 g of pyrazole oxalate, and the yield was 78%.
References:
CN110003107,2019,A Location in patent:Paragraph 0024; 0045-0068
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