A kind of preparation method of 1-(3-methyl-1-phenyl-1h-pyrazole-5-yl) piperazine
A technology of piperazine and phenyl, which is applied in the field of preparation of nitrogen-containing heterocyclic compounds, can solve the problems of being unsuitable for large-scale production, unsuitable for industrialized large-scale production, and high production costs, and achieve maximum implementation value and social and economic benefits. The effect of easy control of conditions and short reaction steps
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[0031] The invention provides a kind of 1-(3-methyl-1-phenyl-1H-pyrazol-5-yl)piperazine (formula ) preparation method, using 3-oxo-dithiobutyric acid methyl ester (formula IV), piperazine (formula III) and phenylhydrazine (formula II) as starting materials, through nucleophilic substitution, acid-catalyzed cyclization, Compound I can be prepared.
[0032] The reaction formula is as follows:
[0033]
[0034] The method overcomes the disadvantage of using highly toxic or expensive reagents in the prior art, has low cost and high yield, is suitable for industrial production, and has high economic benefits.
[0035] The following examples illustrate the present invention in further detail.
Embodiment 1
[0037] Add 500ml of ethanol to a dry and clean 1L four-necked bottle, start stirring, then add 50.0g (337mmol) of compound IV and 30.5g (354mmol) of compound III, raise the temperature of the system to 70-80°C and keep it for 5h, then cool down the reaction system To 45-50°C, add 38.3g (354mmol) of phenylhydrazine, add 0.5g of glacial acetic acid, raise the temperature of the system again to 70-80°C and keep it warm for 2h, and take samples to track until the reaction is complete. After the reaction is complete, cool the system down to 40-45°C, concentrate under reduced pressure until there is almost no distillate, cool the system down to 20-30°C, add 300ml of tap water, add concentrated hydrochloric acid dropwise to adjust the pH to 2-3, use isopropyl acetate as the water phase Extract 2 times with 200ml of ester, adjust the pH of the water phase to 10-11 with 30% sodium hydroxide, a off-white solid precipitates, cool the system to 0-5°C and keep it for 1 hour, then filter to ...
Embodiment 2
[0040] Add 500ml of ethanol to a dry and clean 1L four-necked bottle, start stirring, then add 50.0g (337mmol) of compound IV and 37.7g (438mmol) of compound III, raise the temperature of the system to 70-80°C and keep it for 5h, then cool down the reaction system To 45-50°C, add 47.4g (438mmol) of phenylhydrazine, add 0.5g of glacial acetic acid, raise the temperature of the system to 70-80°C and keep it warm for 2h, take samples to track until the reaction is complete. After the reaction is complete, cool the system down to 40-45°C, concentrate under reduced pressure until there is almost no distillate, cool the system down to 20-30°C, add 300ml of tap water, add concentrated hydrochloric acid dropwise to adjust the pH to 2-3, use isopropyl acetate as the water phase Ester extraction (200ml each time, 2 extractions), the water phase was adjusted to pH 10-11 with 30% sodium hydroxide, off-white solid precipitated, the system was cooled to 0-5°C and kept for 1 hour, then filter...
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