CN112409287A - Oxazolecarboxamide intermediate and preparation method of oxazolecarboxamide - Google Patents
Oxazolecarboxamide intermediate and preparation method of oxazolecarboxamide Download PDFInfo
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- C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
- C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
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Abstract
The application provides an metamifop intermediate and a preparation method of metamifop, wherein liquid alkali reacts with (R) - (+) -2- (4-hydroxyphenoxy) propionic acid to generate propionic acid sodium salt; adding toluene into the sodium propionate after the pH value is adjusted to a certain value, replacing a solvent to dehydrate under a low-temperature negative pressure state, and finishing dehydration when the water content in a system is less than 0.1%; after dehydration, adding 2, 6-dichlorobenzoxazolone and uniformly mixing to obtain a mixed system; adding potassium carbonate and tetrabutylammonium bromide serving as a catalyst into the mixed system; after the reaction is complete, cooling the system to room temperature, adding a certain amount of water, layering, allowing the upper layer of toluene to enter a toluene recovery system, and allowing the lower layer of water phase which is an acid-out raw material to enter an acidification system; and (3) separating out the materials from the water phase in a manner of dripping hydrochloric acid, regulating the pH value of the water phase to be 1-2, centrifuging the materials, and drying to obtain the condensate, namely the hydroxyphenoxypropionic acid.
Description
Technical Field
The application relates to the technical field of preparation of metamifop herbicides, in particular to a metamifop intermediate and a preparation method of metamifop.
Background
Metamifop (Metamifop) is an aryloxy phenoxy propionate herbicide developed by Korean chemical technology research institute, can well prevent and kill most annual gramineous weeds, is different from most herbicides, is safe to rice, can effectively prevent and kill main weeds in paddy fields, such as barnyard grass, moleplant, crab grass and goosegrass, and is mainly used for weeding in transplanted and direct-seeded paddy fields. The metamifop has low toxicity, is safe to the environment and has wide miscibility, is expected to be used for weeding other crops and lawns, and is a herbicide with great development prospect. Metamifop is a novel, efficient, low-toxicity and environment-friendly aryloxy-phenoxy propionate herbicide, belongs to aryloxy-phenoxy propionate herbicides, and has the action mechanism of inhibiting acetyl coenzyme A carboxylase, wherein the effective ingredients need to reach the target in plants to play a role in weed control. The solvent and the surfactant respectively play roles in softening the waxy layer of the leaf surface and opening the stomata of the plant, so that the effective ingredients enter the plant body to play a role.
The traditional production process of metamifop mainly comprises the working procedures of ring closing, monochlorination, alkaline hydrolysis, sulfhydrylation, acidification, dichlorination, synthesis, finished product drying and the like. In the process of reacting the intermediate 2, 6-dichlorobenzoxazolone (hereinafter referred to as "dichlorinate") with (R) - (+) -2- (4-hydroxyphenoxy) propionic acid (hereinafter referred to as "propionic acid") to form a condensate, the main operation steps are as follows: firstly, propionic acid reacts under an alkaline environment to generate sodium propionate, and the reaction formula is as follows:
then adding DMF solvent into the sodium propionate salt, and after adding the catalyst, controlling and dropwise adding the solution of dichlorinated products to generate a condensate, namely hydroxyphenoxypropionic acid, wherein the reaction formula is as follows:
in the above method for preparing the condensate hydroxyphenoxypropionic acid, a mixed solvent of 30% of water and 70% of N, N-dimethylformamide DMF is used as a reaction environment, and the yield of the reaction of the method is usually not higher than 80% because dichlorinated products are decomposed by water. Meanwhile, the post-treatment of waste liquid of a DMF and water system is not ideal, so that the production cost is high.
Disclosure of Invention
The application provides an metamifop intermediate and a preparation method of metamifop, which remove water in an environment where propionic acid forms sodium salt by adjusting a reaction process, thereby reducing decomposition of dichlorides and improving yield; the toluene solvent is used for replacing a DMF solvent, so that the waste liquid treatment cost is reduced; the organic solvent is used circularly after being layered and distilled, so that the raw material cost and the wastewater treatment cost are reduced.
The technical scheme adopted by the application for solving the technical problems is as follows:
a preparation method of an metamifop intermediate comprises the following steps:
producing sodium propionate by reacting liquid alkali with (R) - (+) -2- (4-hydroxyphenoxy) propionic acid;
adding toluene into the sodium propionate after the pH value is adjusted to a certain value, replacing a solvent to dehydrate under a low-temperature negative pressure state, and finishing dehydration when the water content in a system is less than 0.1%;
after dehydration, adding 2, 6-dichlorobenzoxazolone and uniformly mixing to obtain a mixed system;
adding potassium carbonate and tetrabutylammonium bromide serving as a catalyst into the mixed system;
after the reaction is complete, cooling the system to room temperature, adding a certain amount of water, layering, allowing the upper layer of toluene to enter a toluene recovery system, and allowing the lower layer of water phase which is an acid-out raw material to enter an acidification system;
and (3) separating out the materials from the water phase in a manner of dripping hydrochloric acid, regulating the pH value of the water phase to be 1-2, centrifuging the materials, and drying to obtain the condensate, namely the hydroxyphenoxypropionic acid.
Optionally, adding potassium carbonate and tetrabutylammonium bromide as a catalyst into the mixed system to react, including:
potassium carbonate and a catalyst tetrabutylammonium bromide are added into a mixed system in a small quantity and multiple times.
A preparation method of metamifop comprises the steps of preparing metamifop intermediate hydroxyphenoxypropionic acid by adopting the preparation method of the metamifop intermediate, and the method further comprises the following steps:
adding metered dichloroethane into the dried hydroxyphenoxypropionic acid, and cooling to 0-5 ℃ under the stirring state;
dropwise adding metered oxalyl chloride into the cooled solution, and after dropwise adding is finished, carrying out heat preservation reaction for 2 hours;
after the heat preservation reaction is finished, heating to 84-86 ℃ and carrying out a first reflux reaction for 4 hours;
after the first reflux reaction is finished, controlling the temperature to be 75-80 ℃, and dropwise adding an N-methyl-2-fluoroaniline solution;
after the dropwise addition of the N-methyl-2-fluoroaniline solution is finished, heating and carrying out a second reflux reaction, wherein the time of the second reflux reaction is 6 hours;
after the second reflux reaction is finished and the yield of the intermediate product is controlled to be qualified, cooling to normal temperature, adding water, stirring, cooling, continuously controlling the temperature to 0-5 ℃, cooling and crystallizing to obtain a mixed solution containing a crude product of metamifop;
centrifuging the mixed solution containing the crude product metamifop, and removing the centrifugal mother solution to obtain a wet material product metamifop;
and drying the wet material product metamifop to obtain the finished product metamifop.
Optionally, in the preparation reaction process of metamifop, the reaction system is configured with a third-stage tail gas absorption system for recovering acid gas generated in the reaction process, and the third-stage tail gas absorption system is always in an open state.
The technical scheme provided by the application comprises the following beneficial technical effects:
the application provides an metamifop intermediate and a preparation method of metamifop, wherein liquid alkali reacts with (R) - (+) -2- (4-hydroxyphenoxy) propionic acid to generate propionic acid sodium salt; adding toluene into the sodium propionate after the pH value is adjusted to a certain value, replacing a solvent to dehydrate under a low-temperature negative pressure state, and finishing dehydration when the water content in a system is less than 0.1%; after dehydration, adding 2, 6-dichlorobenzoxazolone and uniformly mixing to obtain a mixed system; adding potassium carbonate and tetrabutylammonium bromide serving as a catalyst into the mixed system; after the reaction is complete, cooling the system to room temperature, adding a certain amount of water, layering, allowing the upper layer of toluene to enter a toluene recovery system, and allowing the lower layer of water phase which is an acid-out raw material to enter an acidification system; and (3) separating out the materials from the water phase in a manner of dripping hydrochloric acid, regulating the pH value of the water phase to be 1-2, centrifuging the materials, and drying to obtain the condensate, namely the hydroxyphenoxypropionic acid. According to the technical scheme, water in the environment of forming sodium salt by propionic acid is removed by adjusting the reaction process, so that the decomposition of dichlorinated products is reduced, and the yield is improved; the toluene solvent is used for replacing a DMF solvent, so that the waste liquid treatment cost is reduced; the organic solvent is used circularly after being layered and distilled, so that the raw material cost and the wastewater treatment cost are reduced.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a preparation method of an metamifop intermediate provided by an embodiment of the application.
Detailed Description
In order to make the technical solutions in the present application better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application; it is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, fig. 1 shows a method for preparing an metamifop intermediate, according to an embodiment of the present application, which includes the following steps:
the liquid alkali reacts with (R) - (+) -2- (4-hydroxyphenoxy) propionic acid (hereinafter referred to as propionic acid) to generate sodium propionate, and the reaction formula is as follows:
adding toluene into the sodium propionate after the pH value is adjusted to a certain value, replacing a solvent to dehydrate under a low-temperature negative pressure state, and finishing dehydration when the water content in a system is less than 0.1%;
after dehydration, adding 2, 6-dichlorobenzoxazolone and uniformly mixing to obtain a mixed system;
adding potassium carbonate and tetrabutylammonium bromide serving as a catalyst into the mixed system in a small quantity and multiple times;
after the reaction is complete, cooling the system to room temperature, adding a certain amount of water, layering, allowing the upper layer of toluene to enter a toluene recovery system, and allowing the lower layer of water phase which is an acid-out raw material to enter an acidification system;
and (3) separating out the materials from the water phase in a manner of dripping hydrochloric acid, regulating the pH value of the water phase to be 1-2, centrifuging and drying the materials to obtain the condensate hydroxy phenoxy propionic acid, wherein the reaction formula is as follows:
example one:
1. in a 1000ml four-necked flask, 246.8g of 25% caustic soda liquid was added and stirring was turned on.
2. Weighing 132.2g of propionic acid, adding a small amount of propionic acid into the liquid caustic soda for multiple times, controlling the time to be 1h, keeping the temperature at 40-50 ℃ for two hours after the dripping is finished, sampling and analyzing the content of the propionic acid to be less than 0.1%, and entering the next step when the reaction is qualified.
3. Adjusting pH to 12 with 10% hydrochloric acid, adding 400ml toluene frame negative pressure oil-water separation device, and dehydrating until water content is less than 0.05%.
4. After the temperature was reduced to room temperature, 140.2g of dichloro compound in a molten state was added to the flask and stirred uniformly.
5. 77.2g of potassium carbonate and 6g of tetrabutylammonium bromide are added through a feeding funnel for 1 hour.
6. The temperature is raised to 80 ℃ and the reaction is kept for 8 hours, and the sample is taken for analysis, wherein the content of the dichloro-compound is 0.08%.
7. Stopping stirring, and transferring to a pear-shaped separating funnel for layering; taking the lower layer material to a water washing system, and removing the upper layer methylbenzene to a recovery system.
8. And washing and stirring the lower-layer material for 0.5 hour, taking the lower-layer material layer by layer, feeding the lower-layer material into an acid precipitation system, and feeding the upper-layer methylbenzene into a methylbenzene recovery system.
9. Cooling the lower layer material to 0-10 deg.c, and dropping hydrochloric acid slowly to regulate pH to 6-7.
10. Suction filtration, drying, weighing 168.4g and analyzing the content in liquid phase to be 89%.
Example two:
1. in a 1000ml four-necked flask, 246.5g of 25% caustic soda liquid was added and stirring was turned on.
2. Weighing 132.4g of propionic acid, adding a small amount of propionic acid into the liquid caustic soda for multiple times, controlling the time to be 1h, keeping the temperature at 40-45 ℃ for two hours after the dripping is finished, sampling and analyzing the content of the propionic acid to be less than 0.1%, and entering the next step when the reaction is qualified.
3. After the pH value is adjusted to 12 by 10% hydrochloric acid, 400ml of toluene is added to a negative pressure oil-water separation device, and the water is dehydrated to 0.07 percent.
4. After the temperature was reduced to room temperature, 140.3g of a dichloro compound in a molten state was added to the flask and stirred uniformly.
5. 77.0g of potassium carbonate and 6g of tetrabutylammonium bromide are added through a feeding funnel for 1 hour.
6. The temperature is raised to 80 ℃ and the reaction is kept for 8 hours, and the sample is taken for analysis, wherein the content of the dichlorine residue is 0.04%.
7. Stopping stirring, and transferring to a pear-shaped separating funnel for layering; taking the lower layer material to a water washing system, and removing the upper layer methylbenzene to a recovery system.
8. And washing and stirring the lower-layer material for 0.5 hour, taking the lower-layer material layer by layer, feeding the lower-layer material into an acid precipitation system, and feeding the upper-layer methylbenzene into a methylbenzene recovery system.
9. Cooling the lower layer material to 0-10 deg.c, and dropping hydrochloric acid slowly to regulate pH to 6-7.
10. Suction filtration, drying, weighing 177.4g, liquid phase analysis content 91%.
Example three:
1. in a 1000ml four-necked flask, 246.1g of 25% caustic soda liquid was added and stirring was turned on.
2. Weighing 132.5g of propionic acid, adding into the liquid caustic soda for multiple times in small amount, controlling the time to be 1h, keeping the temperature at 40-45 ℃ for two hours after the dripping is finished, sampling and analyzing the propionic acid content to be 0.08%, and entering the next step when the reaction is qualified.
3. Adjusting pH to 12 with 10% hydrochloric acid, adding 400ml toluene frame negative pressure oil-water separation device, and dehydrating until water content is less than 0.05%.
4. After the temperature was reduced to room temperature, 140.2g of dichloro compound in a molten state was added to the flask and stirred uniformly.
5. 77.2g of potassium carbonate and 6g of tetrabutylammonium bromide are added through a feeding funnel for 1 hour.
6. The temperature is raised to 75 ℃ and the reaction is kept for 8 hours, and the sample is taken for analysis, wherein the content of the dichloro-compound is 0.04%.
7. Cooling to room temperature, adding 400ml of water, stirring until the lower layer is completely dissolved, stopping stirring, and transferring to a pear-shaped separating funnel for layering; taking the lower layer material to a water washing system, and removing the upper layer methylbenzene to a recovery system.
8. And washing and stirring the lower-layer material for 0.5 hour, taking the lower-layer material layer by layer, feeding the lower-layer material into an acid precipitation system, and feeding the upper-layer methylbenzene into a methylbenzene recovery system.
9. Cooling the lower layer material to 0-10 deg.c, and dropping hydrochloric acid slowly to regulate pH to 6-7.
10. Suction filtration, drying, weighing 192.5g, liquid phase analysis content 95%.
In this embodiment, a preparation method of metamifop is further provided, and includes that the preparation method of metamifop intermediate is adopted to prepare metamifop intermediate hydroxyphenoxypropionic acid, and the method further includes:
adding metered dichloroethane into the dried hydroxyphenoxypropionic acid, and cooling to 0-5 ℃ under the stirring state;
dropwise adding metered oxalyl chloride into the cooled solution, and after dropwise adding is finished, carrying out heat preservation reaction for 2 hours;
after the heat preservation reaction is finished, heating to 84-86 ℃ and carrying out a first reflux reaction for 4 hours;
after the first reflux reaction is finished, controlling the temperature to be 75-80 ℃, and dropwise adding an N-methyl-2-fluoroaniline solution;
after the dropwise addition of the N-methyl-2-fluoroaniline solution is finished, heating and carrying out a second reflux reaction, wherein the time of the second reflux reaction is 6 hours;
and (4) after the second reflux reaction is finished, controlling the yield of the intermediate product, and carrying out high performance liquid analysis on the intermediate product, wherein the content of the intermediate product is 95-96% and is a qualified product, and the intermediate product is acyl chloride generated by reaction with oxalyl chloride. After the product is qualified, cooling the system to normal temperature, adding water, stirring, cooling, continuously controlling the temperature to 0-5 ℃, cooling and crystallizing to obtain a mixed solution containing a crude product of metamifop;
centrifuging the mixed solution containing the crude product metamifop, and removing the centrifugal mother solution to obtain a wet material product metamifop;
and drying the wet material product metamifop to obtain the finished product metamifop.
In the preparation method of metamifop, the main reaction formula is as follows:
the main side reactions are as follows:
the yield of the reaction product in the step is about 90.25%, and the conversion rate is about 90.25%. The yield of the first chlorination reaction was 95.0% and the conversion of the second condensation reaction was about 95%. About 5% of the by-product etherate formed by the side reaction and by-product oxalic acid aniline remained in the centrifuge wastewater.
In the preparation reaction process of metamifop, a reaction system is provided with a three-stage tail gas absorption system for recovering acid gas generated in the reaction process, and the three-stage tail gas absorption system is always in an open state.
It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
It will be understood that the present application is not limited to what has been described above and shown in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.
Claims (4)
1. The preparation method of the metamifop intermediate is characterized by comprising the following steps:
producing sodium propionate by reacting liquid alkali with (R) - (+) -2- (4-hydroxyphenoxy) propionic acid;
adding toluene into the sodium propionate after the pH value is adjusted to a certain value, replacing a solvent to dehydrate under a low-temperature negative pressure state, and finishing dehydration when the water content in a system is less than 0.1%;
after dehydration, adding 2, 6-dichlorobenzoxazolone and uniformly mixing to obtain a mixed system;
adding potassium carbonate and tetrabutylammonium bromide serving as a catalyst into the mixed system;
after the reaction is complete, cooling the system to room temperature, adding a certain amount of water, layering, allowing the upper layer of toluene to enter a toluene recovery system, and allowing the lower layer of water phase which is an acid-out raw material to enter an acidification system;
and (3) separating out the materials from the water phase in a manner of dripping hydrochloric acid, regulating the pH value of the water phase to be 1-2, centrifuging the materials, and drying to obtain the condensate, namely the hydroxyphenoxypropionic acid.
2. The method for preparing the metamifop intermediate as claimed in claim 1, wherein the adding potassium carbonate and tetrabutylammonium bromide as a catalyst into the mixed system comprises:
potassium carbonate and a catalyst tetrabutylammonium bromide are added into a mixed system in a small quantity and multiple times.
3. A method for producing metamifop, which comprises the step of producing metamifop intermediate hydroxyphenoxypropionic acid by using the method for producing metamifop intermediate according to any one of claims 1 to 2, and the method further comprises the steps of:
adding metered dichloroethane into the dried hydroxyphenoxypropionic acid, and cooling to 0-5 ℃ under the stirring state;
dropwise adding metered oxalyl chloride into the cooled solution, and after dropwise adding is finished, carrying out heat preservation reaction for 2 hours;
after the heat preservation reaction is finished, heating to 84-86 ℃ and carrying out a first reflux reaction for 4 hours;
after the first reflux reaction is finished, controlling the temperature to be 75-80 ℃, and dropwise adding an N-methyl-2-fluoroaniline solution;
after the dropwise addition of the N-methyl-2-fluoroaniline solution is finished, heating and carrying out a second reflux reaction, wherein the time of the second reflux reaction is 6 hours;
after the second reflux reaction is finished and the yield of the intermediate product is controlled to be qualified, cooling to normal temperature, adding water, stirring, cooling, continuously controlling the temperature to 0-5 ℃, cooling and crystallizing to obtain a mixed solution containing a crude product of metamifop;
centrifuging the mixed solution containing the crude product metamifop, and removing the centrifugal mother solution to obtain a wet material product metamifop;
and drying the wet material product metamifop to obtain the finished product metamifop.
4. The method for preparing metamifop as claimed in claim 3, characterized in that during the preparation reaction of metamifop, the reaction system is configured with a three-stage tail gas absorption system for recovering acid gas generated during the reaction, and the three-stage tail gas absorption system is always in an open state.
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| CN114702459A (en) * | 2022-04-02 | 2022-07-05 | 德州绿霸精细化工有限公司 | Method for producing metamifop |
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Application publication date: 20210226 |