Pyridyl phenylurea preparation method

Abstract

The invention refers to a method of preparing the phenyl-urea type fissional-element high-efficacy plant grwoth regulator, pyridyl phenyl-urea N-(2-Cl-4-pyridyl)-N'-phenyl-urea. It uses cheap pyridine as the raw material to make 4-nitryl pyridine nitrogen oxide by oxidization and nitration, makes further halogenation reaction to produce 2-X-4-nitryl pyridine, X=Cl or Br, deoxidizes the 2-X-4-nitryl pyridine to obtain 2-X'-4-amino pyridine and then makes further condensation with phenyl iso-cyanate in toluene reaction medium to obtain the target 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...

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.