Synthesis method of pyrazolone
A pyrazoline and phenyl technology, applied in the field of synthesis of pyrazolones, can solve the problems that organic solvents do not meet green environmental protection requirements, are unfavorable for large-scale production, promotion, and are difficult to obtain.
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Embodiment 1
[0021] 3-Methyl-1-p-methylphenyl-2-pyrazolin-5-one
[0022] Take 12.2g (0.1mol) of p-methylphenylhydrazine and 17.7ml (0.14mol) of ethyl acetoacetate, put them into a round-bottomed flask for shaking, ultrasonically shake for 2 minutes, connect the reflux device, and put them into a microwave reactor at atmospheric pressure with 300W microwave radiation Reflux for 10 minutes to obtain a red viscous liquid, add 20ml of ethyl acetoacetate to dilute and heat to reflux for 5 minutes with 0.1g of activated carbon, filter while hot, cool to room temperature, wash 3 times with 1 / 2 volume of distilled water, wash 3 times with 1 / 2 volume of saturated saline Once, dried over anhydrous magnesium sulfate, and distilled under reduced pressure, the white solid obtained was dissolved in 5ml ethyl acetate at 60°C, crystallized at -25°C for 10 hours, filtered under reduced pressure, and dried in vacuum for 4 hours to obtain 15.9 g of white solid (0.0854 mol), yield 85.4%. mp134~125.5℃
Embodiment 2
[0024] 3-Methyl-1-(2,3-dimethylphenyl)-2-pyrazolin-5-one
[0025] Take 13.6g (0.1mol) of 2,3-dimethylphenylhydrazine and 17.7ml (0.14mol) of ethyl acetoacetate, put them into a round-bottomed flask for shaking, ultrasonically shake for 2min, connect a reflux device, and put it into a microwave reaction at normal pressure Reflux for 10 minutes under 300W microwave radiation to obtain dark red viscous liquid, dilute with 20ml ethyl acetoacetate and heat reflux for 5 minutes with 0.1g activated carbon, filter while hot, cool to room temperature, wash 3 times with 1 / 2 volume of distilled water, 1 / 2 Wash with saturated brine for 3 times, dry over anhydrous magnesium sulfate, and distill under reduced pressure. The resulting white solid was dissolved in 5ml of ethyl acetate at 60°C, crystallized at -25°C for 10 hours, filtered under reduced pressure, and dried under vacuum for 4 hours to obtain white Solid 16.2g (0.0807mol), yield 80.7%. mp152~154.℃
Embodiment 3
[0027] 3-Methyl-1-phenyl-2-pyrazolin-5-one
[0028] Take 10.8g (0.1mol) of phenylhydrazine and 17.7ml (0.14mol) of ethyl acetoacetate, put them into a round-bottomed flask for shaking, ultrasonically shake for 2 minutes, connect the reflux device, put them into a normal-pressure microwave reactor and reflux for 10 minutes under 300W microwave radiation , to obtain a light pink viscous liquid, add 20ml of ethyl acetoacetate to dilute and heat to reflux with 0.1g of activated carbon for 5min, filter while hot, cool to room temperature, wash 3 times with 1 / 2 volume of distilled water, and 3 times with 1 / 2 volume of saturated saline , dried over anhydrous magnesium sulfate, and distilled under reduced pressure, the resulting white solid was dissolved in 5ml ethyl acetate at 60°C, crystallized at -25°C for 10 hours, filtered under reduced pressure, and vacuum-dried for 4 hours to obtain 14.3g (0.0821mol ), yield 82.1%. mp126~128.℃ (Document: 127.5~128.5℃)
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