CN116283661A - 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and preparation method thereof - Google Patents

2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and preparation method thereof Download PDF

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CN116283661A
CN116283661A CN202310318323.4A CN202310318323A CN116283661A CN 116283661 A CN116283661 A CN 116283661A CN 202310318323 A CN202310318323 A CN 202310318323A CN 116283661 A CN116283661 A CN 116283661A
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benzonitrile
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史海兵
何乐
陆识存
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Allchemy Co ltd
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Abstract

The invention discloses a 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and a preparation method thereof. The preparation method comprises the following steps of S1, carrying out cyanolysis reaction on raw materials comprising 1,2, 3-trifluoro-6-nitrobenzene and a cyanating agent to obtain 2, 3-difluoro-6-nitro-benzonitrile; s2, carrying out hydrogenation reduction reaction on 2, 3-difluoro-6-nitro-benzonitrile to obtain 2, 3-difluoro-6-amino-benzonitrile; step S3, carrying out diazotization reaction on the 2, 3-difluoro-6-amino-benzonitrile and a diazotizing reagent to obtain diazonium salt; and step S4, carrying out trifluoromethylation reaction on the diazonium salt and a trifluoromethylating reagent to obtain the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile. The preparation method uses cheap 1,2, 3-trifluoro-6-nitrobenzene as raw material, and obtains the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound with high yield simply, quickly and with low cost.

Description

2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and preparation method thereof
Technical Field
The invention relates to the technical field of synthesis of 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compounds, in particular to a 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and a preparation method thereof.
Background
The N' - (cyclopropylmethoxy) benzamide oxime compound is used as a pesticide fungicide, has the advantages of unique action mechanism, safety, high efficiency, low toxicity, easy degradation, high targeting property on pathogenic bacteria, novel structure, broad spectrum and high efficiency, and different action modes from the existing bactericides, and becomes a new hot spot for the research of bactericides. At present, with the large-scale application of chemical agents, environmental pollution is increased, the generation of pathogenic microorganism resistance is unavoidable, meanwhile, food safety problems are increasingly concerned, and pesticide reduction and production of safe and environment-friendly antibacterial agents are beneficial to sustainable development.
2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is used as an important intermediate of N' - (cyclopropylmethoxy) benzamide oxime compound pesticides, butyl lithium (the price of butyl lithium is gradually increased in recent years) is used in the existing synthesis method, high-temperature fluoro is needed, the cost is high due to a plurality of reaction steps, the equipment requirement is high, and the industrial production is not facilitated, so that a new route for synthesizing 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is needed to be developed, the cost is reduced, and three wastes are reduced.
In the data which can be referred to, the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is synthesized, basically 3, 4-difluoro-trifluoromethyl benzene is used, aldehyde is prepared by fluoro and lithiation, then the aldehyde is reacted with hydroxylamine hydrochloride, finally dehydration is carried out, the price of butyl lithium is increased in recent years, and high-temperature fluoro is needed, so that the cost is high, and the industrial implementation is not facilitated.
Figure BDA0004150800920000011
Disclosure of Invention
The invention mainly aims to provide a 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and a preparation method thereof, which are used for solving the problem of high cost in the preparation method of the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound in the prior art.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile, comprising: step S1, carrying out cyanolysis reaction on raw materials comprising 1,2, 3-trifluoro-6-nitrobenzene and a cyanidation reagent to obtain 2, 3-difluoro-6-nitro-benzonitrile; s2, carrying out hydrogenation reduction reaction on 2, 3-difluoro-6-nitro-benzonitrile to obtain 2, 3-difluoro-6-amino-benzonitrile; step S3, carrying out diazotization reaction on the 2, 3-difluoro-6-amino-benzonitrile and a diazotizing reagent to obtain diazonium salt; and step S4, carrying out trifluoromethylation reaction on the diazonium salt and a trifluoromethylating reagent to obtain the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Further, in the step S1, the cyanating agent is sodium cyanide and/or potassium cyanide, and preferably the molar ratio of the cyanating agent to 1,2, 3-trifluoro-6-nitrobenzene is 1.1-1.5: 1.
further, in the step S1, the raw material further includes a first catalyst, preferably the first catalyst has a molar number of 5 to 10% of that of 1,2, 3-trifluoro-6-nitrobenzene, and preferably the first catalyst is cuprous iodide.
Further, in the step S1, the raw material further includes a phase transfer catalyst, preferably, the mole number of the phase transfer catalyst is 10 to 30% of the mole number of 1,2, 3-trifluoro-6-nitrobenzene, and preferably, the mole ratio of the first catalyst to the phase transfer catalyst is 0.16 to 0.5:1, preferably the phase transfer catalyst is tetrabutylammonium bromide and/or tetrabutylammonium chloride.
Further, in the above step S1, the cyanation reaction is carried out in a solvent, preferably any one or more selected from N, N-dimethylformamide, N-dimethylacetamide and N-methyl-pyrrolidone, preferably at a temperature of 20 to 50 ℃, and preferably for a time of 12 to 24 hours.
Further, in the above step S2, the hydrogenation reduction reaction is carried out under the action of a second catalyst, preferably the second catalyst has a molar amount of 0.001 to 0.005 times the amount of the 2, 3-difluoro-6-nitro-benzonitrile compound, and preferably the second catalyst is selected from any one or more of 3% palladium on carbon, 1% palladium on carbon and 5% palladium on carbon.
Further, in the step S2, the hydrogen partial pressure of the hydrogenation reduction reaction is 0.1-0.5 MPa, the temperature of the hydrogenation reduction reaction is preferably 20-25 ℃, and the time of the hydrogenation reduction reaction is preferably 8-24 hours.
Further, in the step S4, the diazotizing agent is selected from one or more of sodium nitrite, nitroso tert-butyl ester and nitroso tert-amyl ester, preferably the diazotizing agent is 1.1 to 1.3 times of the mole number of 2, 3-difluoro-6-amino-benzonitrile, preferably the pH value of the diazotizing reaction is 1 to 3, and preferably the temperature of the diazotizing reaction is 0 to 10 ℃.
Further, in the step S4, the trifluoromethylating agent is sodium trifluoromethylsulfinate and/or potassium trifluoromethylsulfinate, preferably 3 to 4 times the mole number of diazonium salt; preferably, an oxidant is added in the trifluoromethylation reaction, preferably the addition amount of the oxidant is 2-3 times of the mole number of diazonium salt, preferably the oxidant is tert-butyl peroxide; preferably, a third catalyst is added to catalyze the trifluoromethylation reaction, preferably, the addition amount of the third catalyst is 2-3 times of the mole number of diazonium salt, and preferably, the third catalyst is cuprous chloride and/or cuprous bromide; preferably, the pH of the trifluoromethylation reaction is 1 to 3, and preferably the temperature of the trifluoromethylation reaction is 0 to 10 ℃.
According to another aspect of the present invention, there is provided a 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound prepared by the above-described preparation method.
By using the technical scheme of the invention, 1,2, 3-trifluoro-6-nitrobenzene is used as a raw material, firstly reacts with cuprous cyanide or sodium cyanide to obtain 2, 3-difluoro-6-nitro-benzonitrile, then hydrogenates to obtain 2, 3-difluoro-6-amino-benzonitrile, and then completes diazotization reaction and then reacts with trifluoromethyl to prepare the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile. The preparation method uses cheap 1,2, 3-trifluoro-6-nitrobenzene as a raw material, and is simple, quick and low in cost through the reaction steps with mild reaction conditions, so that the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound with high yield is obtained, and the preparation method is more suitable for industrial production.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
fig. 1 shows a mass spectrum of 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile provided according to example 1 of the present invention.
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
As analyzed in the background of the present application, the preparation method of 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound in the prior art has a problem of high cost, and in order to solve the problem, the present application provides a 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and a preparation method thereof.
In one exemplary embodiment of the present application, there is provided a method for preparing 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile, the method comprising: step S1, carrying out cyanolysis reaction on raw materials comprising 1,2, 3-trifluoro-6-nitrobenzene and a cyanidation reagent to obtain 2, 3-difluoro-6-nitro-benzonitrile; s2, carrying out hydrogenation reduction reaction on 2, 3-difluoro-6-nitro-benzonitrile to obtain 2, 3-difluoro-6-amino-benzonitrile; step S3, carrying out diazotization reaction on the 2, 3-difluoro-6-amino-benzonitrile and a diazotizing reagent to obtain diazonium salt; and step S4, carrying out trifluoromethylation reaction on the diazonium salt and a trifluoromethylating reagent to obtain the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
The invention takes 1,2, 3-trifluoro-6-nitrobenzene as a raw material, firstly reacts with cuprous cyanide or sodium cyanide to obtain 2, 3-difluoro-6-nitro-benzonitrile, then hydrogenates to obtain 2, 3-difluoro-6-amino-benzonitrile, and then completes diazotization reaction and then reacts with trifluoromethyl to prepare the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile. The preparation method uses cheap 1,2, 3-trifluoro-6-nitrobenzene as a raw material, and is simple, quick and low in cost through the reaction steps with mild reaction conditions, so that the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound with high yield is obtained, and the preparation method is more suitable for industrial production.
In one embodiment of the present application, in the step S1, the cyanating agent is sodium cyanide and/or potassium cyanide, and preferably the molar ratio of the cyanating agent to 1,2, 3-trifluoro-6-nitrobenzene is 1.1 to 1.5:1.
the above cyanating reagent is more useful for promoting the cyanation reaction with 1,2, 3-trifluoro-6-nitrobenzene, and the preferred molar ratio of cyanating reagent to 1,2, 3-trifluoro-6-nitrobenzene is within the above range, such as 1.1: 1. 1.2: 1. 1.3: 1. 1.4:1 or 1.5:1, so that the excess cyanating agent is more favorable for improving the conversion rate of the 1,2, 3-trifluoro-6-nitrobenzene as much as possible.
In one embodiment of the present application, in the step S1, the raw material further includes a first catalyst, preferably, the mole number of the first catalyst is 5 to 10% of that of 1,2, 3-trifluoro-6-nitrobenzene, and preferably, the first catalyst is cuprous iodide.
The catalyst with the content (such as 5%, 6%, 7%, 8%, 9% or 10% of the mole number of the first catalyst) can help to improve the efficiency and effect of the cyanation reaction with the 1,2, 3-trifluoro-6-nitrobenzene and the cyanating agent under the catalysis of the catalyst with the mole number of the first catalyst being 5%, 6%, 7%, 8%, 9% or 10%.
In one embodiment of the present application, in the step S1, the raw material further includes a phase transfer catalyst, preferably, the mole number of the phase transfer catalyst is 10 to 30% of the mole number of 1,2, 3-trifluoro-6-nitrobenzene, and preferably, the mole ratio of the first catalyst to the phase transfer catalyst is 0.16 to 0.5:1, preferably the phase transfer catalyst is tetrabutylammonium bromide and/or tetrabutylammonium chloride.
The addition of a phase transfer catalyst (e.g., 10%, 15%, 20%, 25% or 30% of the mole number of the phase transfer catalyst is 1,2, 3-trifluoro-6-nitrobenzene) as a cocatalyst helps to promote the further reaction of the cyanation reaction, preferably, the above phase transfer catalyst species, the mole ratio of the first catalyst to the phase transfer catalyst (e.g., 0.16:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1) helps to improve the synergistic catalytic effect of the first catalyst and the phase transfer catalyst, so that the yield of the target product of the cyanation reaction is higher, and the yield of the isomerized byproduct is reduced.
In some embodiments of the present application, it is preferable that the above-mentioned step S1 is performed in a solvent, preferably any one or more selected from N, N-dimethylformamide, N-dimethylacetamide and N-methyl-pyrrolidone, and the temperature of the cyanation reaction is preferably 20 to 50 ℃, and the time of the cyanation reaction is preferably 12 to 24 hours, so as to help to improve the efficiency and effect of the cyanation reaction, and to obtain 2, 3-difluoro-6-nitro-benzonitrile with high yield and purity as much as possible.
The target product 2, 3-difluoro-6-nitro-benzonitrile is generated by the cyanation reaction, and the isomer of the target product is inevitably generated, particularly the more the reaction temperature is high, the more the nitro para substitution of the 1,2, 3-trifluoro-6-nitrobenzene is generated, the higher the isomer is, and the cyanation reaction still has higher reaction speed and high selectivity under the lower temperature of the cyanation reaction by adding the first catalyst and the phase transfer catalyst.
In some embodiments of the present application, it is preferable that in the step S2, the hydrogenation reduction reaction is performed under the action of a second catalyst, preferably the second catalyst has a molar number of 0.001 to 0.005 times that of the 2, 3-difluoro-6-nitro-benzonitrile compound, and preferably the second catalyst is selected from any one or more of 3% palladium on carbon, 1% palladium on carbon and 5% palladium on carbon, so as to facilitate improving the efficiency and effect of the hydrogenation reduction reaction.
In one embodiment of the present application, in the step S2, the hydrogen partial pressure of the hydrogenation reduction reaction is 0.1 to 0.5MPa, preferably the temperature of the hydrogenation reduction reaction is 20 to 25 ℃, and preferably the time of the hydrogenation reduction reaction is 8 to 24 hours. The above conditions of the hydrogenation reduction reaction are preferable to improve the efficiency and effect of the hydrogenation reduction reaction, and the hydrogenation reduction reaction is preferably carried out in toluene, or the like.
In one embodiment of the present application, in the step S4, the diazotizing agent is selected from any one or more of sodium nitrite, nitroso tertiary butyl ester and nitroso tertiary amyl ester, preferably the diazotizing agent is 1.1 to 1.3 times of the mole number of 2, 3-difluoro-6-amino-benzonitrile, preferably the pH value of the diazotizing reaction is 1 to 3, preferably the temperature of the diazotizing reaction is 0 to 10 ℃.
The kinds and the amounts of the above diazotizing agent are both useful for improving the efficiency of the diazotizing reaction, and the preferable temperature of the diazotizing reaction is useful for reducing the occurrence of side reactions as much as possible and improving the safety of the reaction, and the pH of the above diazotizing reaction is preferably controlled within the above range by the addition of hydrochloric acid, thereby further improving the efficiency of the diazotizing reaction.
In one embodiment of the present application, in the step S4, the trifluoromethylating agent is sodium trifluoromethylsulfinate and/or potassium trifluoromethylsulfinate, preferably 3 to 4 times the mole number of diazonium salt; preferably, an oxidant is added in the trifluoromethylation reaction, preferably the addition amount of the oxidant is 2-3 times of the mole number of diazonium salt, preferably the oxidant is tert-butyl peroxide; preferably, a third catalyst is added to catalyze the trifluoromethylation reaction, preferably, the addition amount of the third catalyst is 2-3 times of the mole number of diazonium salt, and preferably, the third catalyst is cuprous chloride and/or cuprous bromide; preferably, the pH of the trifluoromethylation reaction is 1 to 3, and preferably the temperature of the trifluoromethylation reaction is 0 to 10 ℃.
The type and the amount of the preferred trifluoromethylating agent, the pH value and the temperature of the trifluoromethylation reaction are all conducive to improving the trifluoromethylation efficiency of diazonium salt, and the addition of the oxidant and the third catalyst both improve the trifluoromethylation reaction activity. Wherein, based on the acidic condition of diazotization, the pH value is regulated and controlled by adding alkaline substances such as sodium bicarbonate and the like into a diazonium salt product system.
In another exemplary embodiment of the present application, a 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound is provided, the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound being prepared by a prior preparation method.
The preparation method is simple, quick and low in cost, the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound with high yield is obtained, hydroxylamine hydrochloride is used as an oximating agent, absolute methanol is used as a solvent, the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound is subjected to oxime synthesis to form 2, 3-difluoro-N-hydroxy-6- (trifluoromethyl) benzamide, and the yield can reach 80% after crystallization and purification, so that the preparation cost of N' - (cyclopropylmethoxy) benzamide oxime pesticide compounds is greatly reduced.
The advantageous effects of the present application will be further described below with reference to examples.
Example 1
The first step: cyanogen decomposition
Figure BDA0004150800920000051
50g of 1,2, 3-trifluoro-6-nitrobenzene (0.282 mol) and 200mL of DMF are added into a 500mL three-necked flask, after nitrogen replacement, the mixture is stirred to dissolve, 20.8g of sodium cyanide (0.424 mol) is added below the temperature of 20 ℃ and is stirred to react for 12 hours, after the sampling is qualified, the mixture is concentrated under vacuum below the temperature of 90 ℃ to remove the solvent, after 200g of ethyl acetate is used for dissolving the solid, 50g of water is used for washing for a plurality of times until the pH=7, the mixture is concentrated below the temperature of 80 ℃ to remove the solvent, and petroleum ether is used for 90-120: the ethyl acetate=20:1 mixed solvent was purified by passing through 15g of chromatography silica gel 60 to 100 mesh, and the solvent was concentrated to obtain 36.8g of 2, 3-difluoro-6-nitro-benzonitrile as a qualified product, whose yield was 71% (theoretical yield: 51.9 g).
And a second step of: hydrogenation
Figure BDA0004150800920000061
50g of 2, 3-difluoro-6-nitro-benzonitrile (0.271 mol), 200g of toluene and 0.05g of 3% palladium carbon are added into a 2L stainless steel hydrogenation kettle, after the addition, the high-pressure hydrogenation kettle is replaced by 0.1MPa nitrogen for three times, leak detection is carried out, after no leak is confirmed, the high-pressure hydrogenation kettle is replaced by 0.1MPa hydrogen for three times, and then the temperature is controlled to be 20-25 ℃ and the pressure is controlled to be 0.1MPa for 24 hours. Sampling, namely, after passing through the sample, replacing nitrogen with 0.1MPa for three times, decompressing, disassembling the hydrogenation kettle, pouring out hydrogenation liquid, flushing the inner wall of the hydrogenation kettle by using a small amount of toluene, filtering palladium carbon by using filter paper after passing through the sample, immersing the palladium carbon by using water, loading the sample, and concentrating the filtrate to remove the solvent at the temperature of below 80 ℃ to obtain 50g of 2, 3-difluoro-6-amino-benzonitrile crude product, wherein the yield is 100% (theoretical yield: 50 g).
Third and fourth steps: diazotisation and trifluoromethylation
Figure BDA0004150800920000062
To a 500mL three-necked flask at 0℃were added 20g of crude 2, 3-difluoro-6-amino-benzonitrile (0.13 mol) and 33.9g of 28% hydrochloric acid solution (0.26 mol), and after the addition, the mixture was stirred for 1 minute. 9.9g of sodium nitrite (0.143 mol) is slowly added at the temperature of 0 ℃ and after the addition is finished, the reaction is continued for 20 minutes at the temperature of 0 ℃ so as to form diazonium salt.
A500 mL three-necked flask was prepared, and 8.7g of sodium hydrogencarbonate (0.104 mol), 60.8g of sodium trifluoromethylsulfinate (0.39 mol), 7.7g of cuprous chloride (0.078 mol), 29g of t-butanol peroxide (0.325 mol) and 50mL of acetonitrile were added to the flask and stirred uniformly. And adding diazonium salt dropwise at the temperature of 0 ℃, and reacting for 20 hours at the temperature of 0 ℃ after the dropwise addition. After the reaction was completed, the filter paper was suction-filtered through a layer of celite, and the filtrate was washed to neutrality with 50mL of 10% brine. The reaction solution was concentrated at a temperature of 70℃or below to give 22.8g of a crude 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile product in a yield of 85% (theoretical yield: 26.9 g), and the mass spectrum was as shown in FIG. 1 (by a gas chromatograph-mass spectrometer), and the molecular ion peak of 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile was found as 207.1 in FIG. 1.
Example 2
The difference from example 1 is that the amount of 1,2, 3-trifluoro-6-nitrobenzene added in the cyanation step is unchanged, and the molar ratio of sodium cyanide to 1,2, 3-trifluoro-6-nitrobenzene is 1.1:1, finally obtaining the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 3
The difference from example 1 is that the amount of 1,2, 3-trifluoro-6-nitrobenzene added in the cyanation step is unchanged, and the molar ratio of sodium cyanide to 1,2, 3-trifluoro-6-nitrobenzene is 1:1, finally obtaining the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 4
The difference from example 1 is that in the cyanation step, the addition amount of 1,2, 3-trifluoro-6-nitrobenzene is not changed, 5% of cuprous iodide is added, and finally 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is obtained.
Example 5
The difference from example 1 is that in the cyanation step, the addition amount of 1,2, 3-trifluoro-6-nitrobenzene is unchanged, 10% of cuprous iodide is added, 10% of tetrabutylammonium bromide is added, and the molar ratio of cuprous iodide to tetrabutylammonium bromide is 1:1, finally obtaining the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 6
The difference from example 1 is that in the cyanation step, the addition amount of 1,2, 3-trifluoro-6-nitrobenzene is unchanged, 10% of cuprous iodide is added, 20% of tetrabutylammonium bromide is added, and the molar ratio of cuprous iodide to tetrabutylammonium bromide is 1:2, finally obtaining the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 7
The difference from example 1 is that in the cyanation step, the addition amount of 1,2, 3-trifluoro-6-nitrobenzene is unchanged, 10% of cuprous iodide is added, 30% of tetrabutylammonium bromide is added, and the molar ratio of cuprous iodide to tetrabutylammonium bromide is 1:3, finally obtaining the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 8
The difference from example 1 is that in the cyanation step, the cyanation reaction temperature is 15℃and 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is finally obtained.
Example 9
The difference from example 1 is that in the cyanation step, the cyanation reaction temperature is 50℃and 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is finally obtained.
Example 10
The difference from example 1 is that in the hydrogenation step, the amount of hydrogenated 2, 3-difluoro-6-nitro-benzonitrile was not changed, and 3% palladium on carbon was 0.003 times the mass of 2, 3-difluoro-6-nitro-benzonitrile, and the hydrogenation time was 17 hours, to finally obtain 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 11
The difference from example 1 is that in the hydrogenation step, the amount of 2, 3-difluoro-6-nitro-benzonitrile was unchanged, the hydrogen partial pressure was 0.5MPa, the hydrogenation reaction temperature was 25℃and the hydrogenation time was 8 hours, and finally 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile was obtained.
Example 12
The difference from example 1 is that in the diazotizing step, the amount of 2, 3-difluoro-6-amino-benzonitrile is unchanged, and sodium nitrite is 1.2 times the amount of 2, 3-difluoro-6-amino-benzonitrile substance, finally 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is obtained.
Example 13
The difference from example 1 is that in the diazotizing step, the amount of 2, 3-difluoro-6-amino-benzonitrile is unchanged, and sodium nitrite is 1.3 times the amount of 2, 3-difluoro-6-amino-benzonitrile material, finally 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is obtained.
Example 14
The difference from example 1 is that in the diazotizing step, the amount of 2, 3-difluoro-6-amino-benzonitrile is not changed, and the diazotizing agent is nitroso tertiary amyl ester, and finally 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is obtained.
Example 15
The difference from example 1 is that in the trifluoromethylation step, the amount of diazonium salt is not changed, the pH value of the trifluoromethylation reaction is 3, the temperature of the trifluoromethylation reaction is 0 ℃, and finally the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is obtained.
Example 16
The difference from example 1 is that the amount of diazonium salt is not changed in the trifluoromethylation step, and sodium trifluoromethylsulfinate is 2 times the mole number of diazonium salt, to finally obtain 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
Example 17
The difference from example 1 is that the amount of diazonium salt is not changed in the trifluoromethylation step, and t-butanol peroxide is 2 times the mole number of diazonium salt, and finally 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile is obtained.
The yields of 2, 3-difluoro-6-nitro-benzonitrile, 2, 3-difluoro-6-amino-benzonitrile, 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile in examples 1 to 17 above are shown in Table 1, respectively.
TABLE 1
Figure BDA0004150800920000081
Figure BDA0004150800920000091
From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:
the invention takes 1,2, 3-trifluoro-6-nitrobenzene as a raw material, firstly reacts with cuprous cyanide or sodium cyanide to obtain 2, 3-difluoro-6-nitro-benzonitrile, then hydrogenates to obtain 2, 3-difluoro-6-amino-benzonitrile, and then completes diazotization reaction and then reacts with trifluoromethyl to prepare the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile. The preparation method uses cheap 1,2, 3-trifluoro-6-nitrobenzene as a raw material, and is simple, quick and low in cost through the reaction steps with mild reaction conditions, so that the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound with high yield is obtained, and the preparation method is more suitable for industrial production.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A process for the preparation of 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile, said process comprising:
step S1, carrying out cyanolysis reaction on raw materials comprising 1,2, 3-trifluoro-6-nitrobenzene and a cyanidation reagent to obtain 2, 3-difluoro-6-nitro-benzonitrile;
step S2, carrying out hydrogenation reduction reaction on the 2, 3-difluoro-6-nitro-benzonitrile to obtain 2, 3-difluoro-6-amino-benzonitrile;
step S3, diazotizing the 2, 3-difluoro-6-amino-benzonitrile with a diazotizing reagent to obtain diazonium salt; and
and S4, carrying out a trifluoromethylation reaction on the diazonium salt and a trifluoromethylating reagent to obtain 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile.
2. The process according to claim 1, wherein in step S1, the cyanating agent is sodium cyanide and/or potassium cyanide, preferably the molar ratio of the cyanating agent to the 1,2, 3-trifluoro-6-nitrobenzene is 1.1 to 1.5:1.
3. the process according to claim 1 or 2, wherein in step S1, the feedstock further comprises a first catalyst, preferably the first catalyst has a molar number of 5-10% of the molar number of 1,2, 3-trifluoro-6-nitrobenzene, preferably the first catalyst is cuprous iodide.
4. The process according to claim 3, wherein in step S1, the feedstock further comprises a phase transfer catalyst, preferably the number of moles of the phase transfer catalyst is 10 to 30% of the number of moles of the 1,2, 3-trifluoro-6-nitrobenzene, preferably the molar ratio of the first catalyst to the phase transfer catalyst is 0.16 to 0.5:1, preferably the phase transfer catalyst is tetrabutylammonium bromide and/or tetrabutylammonium chloride.
5. The production method according to any one of claims 1 to 4, wherein in the step S1, the cyanation reaction is performed in a solvent, preferably the solvent is selected from any one or more of N, N-dimethylformamide, N-dimethylacetamide, N-methyl-pyrrolidone, preferably the cyanation reaction temperature is 20 to 50 ℃, preferably the cyanation reaction time is 12 to 24 hours.
6. The production method according to any one of claims 1 to 5, wherein in the step S2, the hydrogenation reduction reaction is performed under the action of a second catalyst, preferably the second catalyst has a molar number of 0.001 to 0.005 times the amount of the 2, 3-difluoro-6-nitro-benzonitrile compound, and preferably the second catalyst is selected from any one or more of 3% palladium on carbon, 1% palladium on carbon, and 5% palladium on carbon.
7. The method according to any one of claims 1 to 6, wherein in step S2, the hydrogen partial pressure of the hydrogenation reduction reaction is 0.1 to 0.5MPa, preferably the temperature of the hydrogenation reduction reaction is 20 to 25 ℃, and preferably the time of the hydrogenation reduction reaction is 8 to 24 hours.
8. The method according to any one of claims 1 to 7, wherein in step S4, the diazotizing agent is selected from any one or more of sodium nitrite, nitroso-t-butyl ester, nitroso-t-amyl ester, preferably the diazotizing agent is 1.1 to 1.3 times the mole number of the 2, 3-difluoro-6-amino-benzonitrile, preferably the pH of the diazotizing reaction is 1 to 3, preferably the temperature of the diazotizing reaction is 0 to 10 ℃.
9. The preparation method according to any one of claims 1 to 8, wherein in the step S4, the trifluoromethylating agent is sodium trifluoromethylsulfinate and/or potassium trifluoromethylsulfinate, preferably the trifluoromethylating agent is 2 to 4 times the molar number of the diazonium salt;
preferably, an oxidizing agent is added in the trifluoromethylation reaction, preferably, the addition amount of the oxidizing agent is 2-3 times of the mole number of the diazonium salt, preferably, the oxidizing agent is tert-butyl peroxide;
preferably, a third catalyst is added to catalyze the trifluoromethylation reaction, preferably, the addition amount of the third catalyst is 2-3 times of the mole number of the diazonium salt, and preferably, the third catalyst is cuprous chloride and/or cuprous bromide;
preferably, the pH of the trifluoromethylation reaction is 1 to 3, and preferably the temperature of the trifluoromethylation reaction is 0 to 10 ℃.
10. A 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound, characterized in that the 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound is produced by the production method according to any one of claims 1 to 9.
CN202310318323.4A 2023-03-28 2023-03-28 2, 3-difluoro-6- (trifluoromethyl) -benzonitrile compound and preparation method thereof Pending CN116283661A (en)

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