- Preparation method of 2, 3-dichloro-5-trifluoromethylpyridine
-
The invention discloses a preparation method of 2, 3-dichloro-5-trifluoromethylpyridine, and belongs to the technical field of organic synthesis. The comprises the following steps: (1) adding 2, 3-dichloro-5-trichloromethylpyridine into an organic solvent under the condition of 20 to 50 DEG C, so as to obtain an organic solution of 2-chloro-5-trichloromethylpyridine; (2) adding fluorinated quaternary ammonium salt and 1, 2-dicyanotetrafluorobenzene into the organic solution of the 2, 3-dichloro-5-trichloromethylpyridine obtained in the step (1), and uniformly mixing to obtain a reaction system; 3) controlling the temperature of the reaction system to be 30-60 DEG C, and reacting to obtain 2, 3-dichloro-5-trifluoromethylpyridine; and 4) filtering the reaction liquid, and carrying out reduced pressure distillation on the obtained filtrate to obtain the 2, 3-dichloro-5-trifluoromethylpyridine. The method can be completed in one step, cheap fluorinated quaternary ammonium salt is selected as a fluorination reagent, and operation is easy; the raw materials are cheap and easily available, the reaction temperature is low, the reaction time is short, and conditions such as high-temperature, high-pressure and dangerous hydrogen fluoride raw materials are avoided; and the yield of the obtained product is 70-90%, and the gas chromatography detection purity is greater than 99.0%.
- -
-
Paragraph 0025-0038
(2021/08/14)
-
- Preparation method 2-3 - dichloro -5 - trifluoromethylpyridine
-
The invention relates to the technical field of organic synthesis, and discloses a preparation method of 2-3 - dichloro -5 - trifluoromethylpyridine, which comprises the following steps: 1) adding 20 - 50 °C, 2 dichloro 3 -methylpyridine into an organic solvent under -5 - conditions to obtain 2 - chloro -5 - trifluoromethylpyridine. 2) To step (1), the organic solution of 2, 3 - dichloro -5 -methylpyridine was added with a fluorinated quaternary ammonium salt, followed by homogeneous mixing, followed by a reaction system. The method provided by 3) has the advantages of cheap and easily available raw materials, 3 - low -5 - reaction temperature and short time, avoids the use of high temperature and high pressure 20 - 50 °C dangerous hydrogen fluoride raw materials and the like, and finally obtains the product yield and of 2 - 6h . and the gas chromatography detection purity is 99.0% greater than 2 70 - 90%.
- -
-
Paragraph 0024-0033
(2021/10/27)
-
- Preparation method of 2,3-dichloro-5-trifluoromethylpyridine
-
The invention provides a preparation method of 2,3-dichloro-5-trifluoromethylpyridine. The method comprises the following steps: carrying out condensation and acidification on 1, 1, 1-trifluoroacetone and nitromethane under the action of alkali to obtain 1-nitro-2-trifluoromethyl propylene; the method comprises the following steps: condensing 1-nitro-2-trifluoromethyl propylene and oxalic acid diester under the action of alkali, and carrying out reduction-cyclization reaction and acidification reaction on the obtained reaction liquid in the presence of a catalyst without separation to obtain a product 2, 3-dihydroxy-5-trifluoromethylpyridine; and then subjecting the 2,3-dihydroxy-5-trifluoromethylpyridine and a chlorination reagent to a chlorination reaction to obtain the 2,3-dichloro-5-trifluoromethylpyridine. The raw materials used in the invention are cheap and easily available, and the reaction selectivity of each step is high. The process does not need special equipment to carry out high-temperature chlorination and high-temperature fluorination reactions and is easy to operate, the target product is high in yield and purity, and the process is suitable for industrial production.
- -
-
Paragraph 0050; 0073-0079
(2021/10/27)
-
- METHOD FOR PREPARING 2,3-DICHLORO-5-TRIFLUOROMETHYLPYRIDINE WITH HIGH SELECTIVITY
-
The present invention discloses a method for preparing 2,3-dichloro-5-trifluoromethylpyridine, comprising at a temperature of 100?150° C. and a pressure of 0.5?5.0 MP, in presence of at least one catalyst selected from supported metal chloride, supported zeolite molecular sieve and supported heteropolyacid, 2-chloro-5-trifluoromethylpyridine reacts with chlorine gas to obtain 2,3-dichloro-5-trifluoromethylpyridine. The preparing method provided by the present invention has advantages such as high selectivity of desired product, high utilization rate of chlorine gas, moderate process condition, simple operation and less three wastes. The present invention also discloses a preparing method for preparing 2-chloro-5-trifluoromethylpyridine, which is capable of reducing unit consumption, reducing separation cost, and improving safety compared to the prior art.
- -
-
Paragraph 0147-0149; 0151-0153; 0156-0157; 0159; 0161
(2020/04/24)
-
- Synthetic method of 2,3-dichloro-5-trifluoromethylpyridine
-
The invention discloses a synthetic method of 2,3-dichloro-5-trifluoromethylpyridine. The method comprises the following steps that 1,2,3-dichloro-5-trichloromethylpyridine and hydrogen fluoride are subjected to a halogen exchange reaction at the temperature of 140-200 DEG C under the action of a catalyst; 2, the product obtained after the halogen exchange reaction is heated at the pressure of 0.15-1.0 MPa for a pressurizing conversion reaction, and 2,3-dichloro-5-trifluoromethylpyridine is obtained. According to the method, 1, 2,3-dichloro-5-trichloromethylpyridine and hydrogen fluoride are used for the reaction; the method is characterized in that under catalysis of the catalyst, trichloromethylpyridine reacts with hydrogen fluoride, the reaction is carried out at normal pressure at first, then the conversion reaction is carried out under certain pressure and temperature, and therefore the defect that in a traditional process, it is dangerous because a reaction is carried out at high temperature and high pressure is overcome. According to the process, reaction conditions are mild, dangerousness is low, a small quantity of waste gas, waste water and waste solids are produced, and separation is easy.
- -
-
Paragraph 0023; 0024; 0025; 0025; 0026-0030
(2017/04/29)
-
- Synthesis method of chlorfluazuron and application of chlorfluazuron in insecticide preparation
-
The invention belongs to the technical field of pesticide preparations, particularly relates to a synthesis method of chlorfluazuron and further discloses an application of chlorfluazuron in insecticide preparation. According to the synthesis method of chlorfluazuron, chlorfluazuron is prepared from 2,3-dichloro-5-(trifluoromethyl)pyridine, 2,6-dichloro-4-aminophenol and 2,6-difluorobenzoyl isocyanate as synthetic raw materials and N,N-dimethylacetamide as a reaction solvent on the basis of a conventional synthesis route in the prior art; under the action of a ZSM molecular sieve based catalyst, not only can synthesis of chlorfluazuron be realized, but also a reaction can be performed with the same reaction solvent, so that the problem of complicated process caused by the fact that solvents are required to be recovered step by step during two-step synthesis of chlorfluazuron in the prior art is solved; compared with the technology in the prior art, the synthesis method of chlorfluazuron has the advantages that the synthesis yield of products is further increased and product content is higher.
- -
-
Paragraph 0030; 0032; 0033; 0036
(2017/07/21)
-
- 2. 3 - dichloro -5 - trifluoro methyl pyridine preparation method
-
The invention provides a preparation method of 2,3-dichloro-5-trifluoromethylpyridine. The preparation method comprises the following steps: (a) 2-chloro-5-chloromethyl pyridine is provided; (b) in the presence of a catalyst, 2-chloro-5-chloromethyl pyridine from the step (a) and a chloride agent chlorine undergo a chlorination reaction so as to obtain 2,3-dichloro-5-trichloromethylpyridine, wherein the catalyst is oxide of copper, chloride of copper or a combination of the oxide of copper and the chloride of copper; (c) after heated and dissolved, 2,3-dichloro-5-trichloromethylpyridine obtained from the step (b) undergoes a fluoridation reaction with hydrogen fluoride under the action of a catalyst so as to obtain 2,3-dichloro-5-trifluoromethylpyridine, wherein the catalyst is oxide of antimony or halide of antimony. By the above method, production cost is reduced, conversion rate is raised, and toxicity is decreased.
- -
-
Paragraph 0021; 0022
(2017/06/13)
-
- A METHOD FOR PRODUCING 2,3-DICHLORO-5-(TRICHLOROMETHYL)PYRIDINE
-
The present invention relates to a novel process for producing of 2,3-dichloro-5-(trichloromethyl)pyridine by using PCl as chlorinating agent at elevated temperature and pressure.
- -
-
Page/Page column 8; 9; 12
(2015/01/09)
-
- Pyridyl(oxy/thio)phenoxy compounds herbicidal compositions and methods
-
Certain novel pyridinyloxyphenoxy alkanoic acids, pyridinylthiophenoxy alkanoic acids, derivatives thereof and related compounds are described. More specifically, these novel compounds bear a fluorine substituent in the 3-position of the pyridinyl group and in the 5-position the substituent is selected from chlorine, CF3, CF2 Cl or CF2 H. These novel compounds exhibit surprising preemergent and postemergent activity in the control of grassy weeds.
- -
-
-
- Certain pyridyloxy or thio-phenoxy-propanoic acids or salts thereof useful as herbicides
-
Certain novel pyridinyloxyphenoxy alkanoic acids, pyridinylthiophenoxy alkanoic acids, derivatives thereof and related compounds are described. More specifically, these novel compounds bear a fluorine substituent in the 3-position of the pyridinyl group and in the 5-position the substituent is selected from chlorine, CF3, CF2 Cl or CF2 H. These novel compounds exhibit surprising preemergent and postemergent activity in the control of grassy weeds.
- -
-
-
- Preparation of (trifluoromethyl)pyridines under liquid phase conditions
-
(Trifluoromethyl)pyridine compounds are prepared by contacting (trichloromethyl)pyridine compounds with hydrogen fluoride in the presence of a catalytic amount of a catalyst selected from the group consisting of FeCl2, FeF2 and mixtures thereof under liquid phase conditions. The (trifluoromethyl)pyridine compounds are useful as intermediates for the preparation of agricultural chemicals.
- -
-
-
- Pyridyl(oxy/thio)phenoxy compounds, herbicidal compositions and methods
-
Certain novel pyridinyloxyphenoxy alkanoic acids, pyridinylthiophenoxy alkanoic acids, derivatives thereof and related compounds are described. More specifically, these novel compounds bear a fluorine substituent in the 3-position of the pyridinyl group and in the 5-position the substituent is selected from chlorine, CF3, CF2 Cl or CF2 H. These novel compounds exhibit surprising preemergent and postemergent activity in the control of grassy weeds.
- -
-
-
- CONVENIENT APPROACHES TO HETEROCYCLES VIA COPPER-CATALYSED ADDITIONS OF ORGANIC POLYHALIDES TO ACTIVATED OLEFINS
-
An efficient method for the synthesis of 2,3-dichloro-5-substituted (Cl, CF3, alkyl) pyridines 29 starting from the 1:1 adducts of the copper-catalysed addition of chloral or the corresponding 2,2-dichloroaldehydes to acrylonitrile is presented.Proper choice of experimental conditions allows the preparation of 29 in one-pot process.Similarly, the CuCl-catalysed reaction of methyl itaconate with several trichloromethyl compounds R-CCl3 gives 6-R-substituted 2-pyrone derivatives 40 via dehalogenation and subsequent thermal ring closure of the primary 1:1-adducts. The new electrophilic 2-pyrone 40b undergoes-cycloaddition reactions with inverse electron demand with a number of olefins and acetylenes, allowing thereby regioselective transfer of a trifluoromethyl group from a simple Freon derivative (1,1,1-trichloro-2,2,2-trifluoroethane) into more complex organic molecules.Finally, the 1:1-adduct of trichloroacetylchloride with methyl acrylate allows a very covenient synthesis of novel N-substituted derivatives 66 of pyroglutamic acid as well as of proline.
- Martin, Pierre,Steiner, Eginhard,Streith, Jacques,Winkler, Tammo,Bellus, Daniel
-
p. 4057 - 4078
(2007/10/02)
-
- Chlorine exchange for fluorine in ring-fluorinated pyridine compounds
-
Ring-fluorinated pyridine compounds are contacted with a chlorinating agent, preferably in the presence of a catalyst, under favorable conditions to yield pyridine compounds having a chlorine substituted in the ring-fluorine position(s).
- -
-
-
- Chlorine exchange for fluorine in 2-fluoro-pyridine compounds
-
2-Fluoro-pyridine compounds are contacted with a chlorinating agent at superatmospheric pressures to yield 2-chloro-pyridine compounds.
- -
-
-
- Preparation of (trifluoromethyl)pyridines
-
Preparation of 3-chloro-2-fluoro-5-(trifluoromethyl)pyridine in a liquid phase halogen exchange reaction from 2,3-dichloro-5-(trichloromethyl)pyridine in the absence of a catalyst.
- -
-
-
- Process for the production of chloropyridines substituted by methyl, trichloromethyl or trifluoromethyl groups
-
Chloropyridines of the formula STR1 wherein either R is chlorine and R' is methyl or trifluoromethyl, or R is methyl, trichloromethyl or trifluoromethyl and R' is chlorine, or R and R' are methyl, can be obtained by a novel, simple process by the addition of trichloroacetaldehyde to methacrylonitrile or α-trifluoromethacrylonitrile, 2,2-dichloropropionaldehyde, pentachloropropionaldehyde or 2,2-dichloro-3,3,3-trifluoropropionaldehyde to acrylonitrile, or 2,2-dichloropropionaldehyde to methacrylonitrile, in the presence of a catalyst, in particular copper powder or copper(I) chloride, and cyclizing the open-chain intermediate obtained. The chloropyridines of the formula (I) are known per se and are suitable for the production of different compounds, in particular of insecticides and herbicides.
- -
-
-
- SOME NEW 2-SUBSTITUTED 5-TRIFLUOROMETHYLPYRIDINES
-
The preparation of the derivatives of 2-amino-, hydrazino-, hydroxy-, and mercapto-5-trifluoromethylpyridines via 2-chloro precursors is describes.Experimental and spectral data of the products together with those of the precursors are presented.
- Haga, Takahiro,Fujikawa, Kan-ichi,Koyanagi, Tohru,Nakajima, Toshio,Hayashi, Kouji
-
p. 117 - 124
(2007/10/02)
-
- Process for producing 5-chloro-β-trifluoromethylpyridines
-
5,6-Dichloro-β-trifluoromethylpyridine or 2,5,6-trichloro-β-trifluoromethylpyridine is produced by reacting 6-chloro-β-trifluoromethylpyridine or 2,6-dichloro-β-trifluoromethylpyridine with chlorine gas to chlorinate the 5-position of pyridine nucleus thereof: (1) at a temperature of 100° C. to 250° C. and at least sufficient amount of chlorine for the reaction; (2) in the presence of the catalyst of amount of at least 40% by weight (based on the 6-chloro or/and 2,6-dichloro-β-trifluoromethylpyridine), the catalyst being chlorides a metallic element selected from the group consisting of iron, tungsten, molybdenum, titanium, and antimony.
- -
-
-
- Herbicidal pyridine compounds
-
Herbicidal 3- and/or 5-halogenomethyl-pyrid-2-yloxyphenoxy compounds and processes for making and using the same. Intermediates for making these compounds and their preparation are also disclosed. Thus, for example, 2-chloro-5-trichloromethylpyridine is prepared by a liquid phase chlorination of 3-methylpyridine under the influence of ultra violet light.
- -
-
-
- Herbicidal compounds
-
A herbicidal sulphonamide compound of the formula (I): STR1 and salts thereof, wherein R1 is a pyridyl group of the formula: STR2 wherein the group X of the pyridyl group represents a fluorine, chlorine, bromine, or iodine atom, or an alkyl radical of 1 to 4 carbon atoms optionally substituted by one or more fluorine or chlorine atoms, and the group Y represents hydrogen, fluorine chlorine, bromine, or iodine or an alkyl radical of 1 to 4 carbon atoms optionally substituted by one or more fluorine or chlorine atoms; R2 represents an alkyl radical of 1 to 6 carbon atoms optionally substituted by one or more fluorine atoms; and R3 is hydrogen or an alkyl radical of 1 to 4 carbon atoms.
- -
-
-
- Herbicidal mono- or di-substituted-2-pyridinyloxy-phenoxy-lower-alkane-carbamates
-
Herbicidal pyridine compounds of the formula (I): STR1 wherein Z may be halogen, or a fluorine- or chlorine-substituted alkyl group of 1 to 4 carbon atoms, and Y may be hydrogen, halogen, or a fluorine- or chlorine-substituted alkyl group of 1 to 4 carbon atoms; X may be an OH group or an acyloxy group; a halogen atom; an amino group, a mono- or di-alkyl amino group, or an alkanoylamido group; an alkoxy group optionally substituted by hydroxy or alkoxy; or a mercapto group, an alkylthio group, or a phenylthio group. The invention also provides herbicidal compositions containing the compounds, and processes for making the compounds.
- -
-
-
