A kind of synthetic technique of 2-hydrazinopyridine derivative
A technology for the synthesis of hydrazinopyridine, which is applied in the field of synthesis technology of 2-hydrazinopyridine derivatives, can solve the problems of low product yield, no safety protection, and many steps, and achieve improved selectivity and reaction rate, Guaranteed selectivity and efficiency, the effect of mild reaction conditions
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Embodiment 1
[0088] (1) Synthesis of 2,3-dichloropyridine (using 2,3,6-trichloropyridine as raw material)
[0089] Add 500g of 2.3.6-trichloropyridine, 1800g of methanol, 20g of mixed catalyst (8%Pt / C:8%Pd / C=1:10) and 45g of pyridine into the reaction kettle, pass in hydrogen, and slowly drop 5 (weight)% sodium hydroxide methanol solution, maintain the pressure in the reactor to be 0.3Mpa, the temperature is 30 DEG C, after the hydrogenation is completed, replace the hydrogen, filter out the Pt / C and Pd / C catalysts for mechanical use, and receive the filtrate atmospheric pressure distillation Methanol is recovered, water is added to the remaining material, the temperature is lowered to crystallize, centrifuged and purified to obtain 2,3-dichloropyridine.
[0090] In step (1), the purity of 2,3-dichloropyridine is 97.6%, and the yield is 88.5%. After crystallization, the gas chromatogram without purification is as follows figure 1 shown.
[0091] (2) Synthesis of 3-chloro-2 hydrazinopyrid...
Embodiment 2
[0095] (1) Synthesis of 2,3-dichloropyridine
[0096] 450g of 2.3.6-trichloropyridine, 1600g of ethanol, 20g of mixed catalyst (8%Pt / C:8%Pd / C=10:1) and 45g of triethylamine were added to the reactor, and hydrogen was introduced while slowly Add dropwise 5 (weight)% sodium hydroxide ethanol solution, keep the pressure in the reactor as 0.25Mpa, and the temperature is 25 to 30°C. After the hydrogenation is completed, replace the hydrogen, filter out the Pt / C and Pd / C catalysts, and receive The filtrate is distilled at normal pressure to recover methanol, water is added to the remaining material, the temperature is lowered to crystallize, centrifuged and purified to obtain 2,3-dichloropyridine.
[0097] In step (1), the purity of 2,3-dichloropyridine is 96.8%, and the yield is 85%, and the gas chromatogram is as follows without purification after crystallization image 3 shown.
[0098] (2) Synthesis of 3-chloro-2 hydrazinopyridine
[0099] Mix 148g of 2,3-dichloropyridine and...
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