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Prepn of pyrido-phenylurea

A technology of pyridylphenylurea and phenylurea, which is applied in the preparation of pyridylphenylurea N--N`-phenylurea, the field of phenylurea-type cytokinin high-efficiency plant growth regulator, can solve the problem of high market price, 2 - Problems such as high toxicity of chloropyridine and limited sources of raw materials, to achieve the effect of reducing production costs, non-toxic or low toxicity, and high product purity

Inactive Publication Date: 2003-11-05
四川省兰月科技开发公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the starting material 2,4-dihydroxypyridine used in the route ① is difficult to obtain and difficult to prepare, and is an industrial production method with a very low yield; the intermediate 2-chloro-4 produced by the route adopted in the route ② -Azidopyridine is extremely explosive, and it is very dangerous even if it is synthesized in a small amount in the laboratory; the raw material 2-chloropyridine used in line ③ is extremely toxic, and the market price is expensive, and the cost of large-scale production is extremely high; although line ④ The synthetic route is simple, but the sources of raw materials are limited, and it is difficult to realize large-scale production; although the route ⑤ picoline is easy to obtain, the synthetic route is also relatively ideal, but the production of high-purity CPPU products is more cumbersome.

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The preparation method of present embodiment 1 is as follows:

[0027] 1. Add 120g of pyridine, 500ml of glacial acetic acid and 200ml of 36% hydrogen peroxide into a 3500ml three-necked flask, heat at 80 for 3 hours, then add 200ml of hydrogen peroxide, continue heating for 6 hours, concentrate under reduced pressure to 500ml, add Add 300ml of water, and add solid sodium carbonate to saturation, cool at room temperature and filter off the insoluble matter, and dry the filtrate with sodium sulfate to obtain 130g of the product, with a boiling point of 139-141°C.

[0028] 2. Pass 310g of chlorine into 678g of pyridine oxide, CCl 4 In a mixture with water, the halogenation reaction was carried out under ultraviolet light for 3 hours, the resulting reactant was extracted with water, the extract was adjusted to pH 11 with 20% NaOH, then distilled and cooled to obtain 856 g of 2,4-dichloropyridine nitrogen oxide , yield 82.2%.

[0029] 3. Dissolve 120g of 2,4-dichloropyrid...

Embodiment 2

[0032] In a 3-liter reactor, under the protection of nitrogen, the chlorination reaction is carried out under the following conditions: pyridine: N: Cl 2 =1:1:2, the temperature is controlled at 165-170, when 249g of pyridine oxide is added, and chlorine is passed for 3 hours, an acidic mixture is obtained, and the pH is adjusted to 8.5-10.0 with ammonia water, and the solvent CCl is recovered 4 , to obtain product 2,4-dichloropyridine 411g, yield 94%

Embodiment 3

[0034] Chlorine gas is directly introduced into 83g of pyridine oxide, and 121g of 2,4-dichloropyridine is obtained at 0-5 to the end point, and the yield is 83%. If the temperature rises to 70°C, the product yield is 8%. increased, the product yield decreased.

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Abstract

The present invention provides the preparation of N-(2-chloro-4-pyrido)-N'-phenylurea as one kind of phenylurea type cytokinin and efficient plant growth regulator. The preparation includes the oxidation and halogenation of pyridine as cheap material to prepare 2, 4-dichloro pyridine nitroxide; the subsequent amination reaction to produce 2-chloro-4-amino pyridine, and final condensation of 2-chloro-4-amino pyridine and phenyl isocyanate in toluene as reaction medium to produce destination product. The present invention has simple operation, short preparation period, easy to obtain materialand low production cost, and is suitable for industrial production.

Description

Technical field: [0001] The present invention relates to a crop growth regulator, in particular to a phenylurea-type cytokinin high-efficiency plant growth regulator pyridylphenylurea N-(2-chloro-4-pyridyl)-N`-benzene Process for the preparation of urea. Background technique: [0002] The molecular structure of pyridylphenylurea of ​​the present invention is: , its chemical name is N-(2-chloro-4-pyridyl)-N`-phenylurea (also known as forchlorfenuron, pyroxuron, CPPU, KT-30, 4PU-30), CPPU is a high Active cytokinin plant growth regulator. Since Okamoto, Suto and others from the Faculty of Pharmacy, University of Tokyo, Japan discovered its high cell division activity in 1981, chemists from various countries have carried out in-depth synthesis research and application development, but due to synthetic routes, starting materials, product purity, and yield Due to the limitation of factors such as production rate, it is difficult to realize industrial production in the end. At...

Claims

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Application Information

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IPC IPC(8): C07D213/81
Inventor 侯勇曾显斌王庭建夏中梅魏敏
Owner 四川省兰月科技开发公司
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