CN110981813A - Synthetic method of 2-cyano-5-aryl-1H-imidazole compound - Google Patents
Synthetic method of 2-cyano-5-aryl-1H-imidazole compound Download PDFInfo
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- CN110981813A CN110981813A CN201911315049.5A CN201911315049A CN110981813A CN 110981813 A CN110981813 A CN 110981813A CN 201911315049 A CN201911315049 A CN 201911315049A CN 110981813 A CN110981813 A CN 110981813A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
- C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
- C07D233/66—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D233/90—Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
- C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
- C07D233/64—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms, e.g. histidine
Abstract
The invention discloses a synthesis method of 2-cyano-5-aryl-1H-imidazole compounds, which comprises the steps of taking α -dihydroxyarylethanone and 2, 2-dialkoxyacetaldehyde as raw materials, synthesizing 2- (dialkoxymethyl) -5-aryl-1H-imidazole compounds through cyclization with a nitrogen source, and then preparing the 2-cyano-5-aryl-1H-imidazole compounds through reactions such as oximation, dehydration and the like.
Description
Technical Field
The invention belongs to the field of synthesis of pesticide raw materials and intermediates, and particularly relates to a synthesis method of a 2-cyano-5-aryl-1H-imidazole compound.
Background
The 2-site dialkoxymethyl of the 2- (dialkoxymethyl) -5-aryl-1H-imidazole compound can form a naked aldehyde group after being acidified to remove acetal protection, the aldehyde group has high reactivity, and can be converted by simple functional groups to generate derivatives such as carboxyl, primary alcohol, amide, imine, cyano and the like, and similar derivatives can be used as intermediates to synthesize various molecules with biological activity, for example, 2-cyano-5-p-tolyl-1H-imidazole is an important intermediate for synthesizing 4-chloro-2-cyano-N, N-dimethyl-5-p-tolylimidazole-1-sulfonamide, 4-chloro-2-cyano-N, N-dimethyl-5-p-tolylimidazole-1-sulfonamide is a novel bactericide developed by Nippon stone original product company, has the advantages of strong pertinence, high efficiency, no cross resistance, long lasting period, safety, environmental protection and the like, has excellent performance, can be widely used for sterilizing melons and vegetables, is also suitable for lawn, egg mycosis represented by downy mildew, rape and plasmodioma disease, the invention discloses a special-based aryl-2-aryl-halogen oxime-1H-1-aryl-2-aryl-halogen compound prepared by a one-2-halogen cyclization reaction method, and a cyclization reaction of aryl-5-cyano-5-cyano-imidazole-cyano-5-imidazole-oxime compound.
At present, the literature discloses methods for preparing 2-cyano-5-aryl-1H-imidazoles, which mainly comprise the following three methods: 1) a method for introducing a cyano group at the 2-position of an imidazole ring by using n-butyllithium as described in patent BR8801098A 1. The raw material n-butyllithium used by the method is expensive, the reaction needs low temperature of-70 ℃, the reaction conditions are harsh, and the water pollution is caused by more waste water in the butyl lithium treatment process; 2) the introduction of a cyano group at position 2 of the imidazole ring by means of the formation of an imide structure is described in patent EP0365030A 1. The raw material 1-methoxy-1-imino-2, 2-diethoxyethane used by the method is difficult to prepare, easy to deteriorate and expensive; 3) the method of patent EP0705823A1 adopts glyoxal to close rings, and then utilizes aldoximyl to introduce cyano group into 2-position of imidazole ring, the synthesis of intermediate 4(5) -chloro-2-cyano-5 (4) - (4' -methylphenyl) imidazole adopts sulfur monochloride as chlorinating agent and reducing agent, the particle size of sulfur generated by reaction is very fine, the treatment process is complex, N-dimethylformamide is used as solvent in the reaction, and the solvent can not be recovered. The above method has the disadvantages of expensive raw materials, harsh operating conditions or unrecoverable solvent.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for synthesizing 2-cyano-5-aryl-1H-imidazole compounds, which has cheap and easily obtained raw materials, simple process and mild reaction conditions. The specific technical scheme is as follows;
a method for synthesizing 2-cyano-5-aryl-1H-imidazole compounds has a reaction chemical formula shown in formula (I),
wherein Ar is an aryl group such as phenyl, substituted phenyl, furyl, thiazolyl, naphthyl, and the like; r is one of chain alkyl such as methyl, ethyl, isopropyl, etc. (CH)2)2、(CH2)3An isocyclic alkyl group; the nitrogen source is one or more of ammonia gas, strong ammonia water, ammonium carbonate, ammonium oxalate, ammonium acetate and the like;
the experimental procedure was as follows:
(1) sequentially adding α -dihydroxy arylethanone, a solvent, 2-dialkoxyacetaldehyde and a liquid or solid nitrogen source into a three-neck round-bottom flask with a thermometer, a reflux condenser tube and a stirring device (if gaseous nitrogen source ammonia is used, the ammonia source is heated and then introduced), wherein the solvent is one or more of N, N-dimethylformamide, dimethyl sulfoxide, water, methanol, ethanol, N-propanol, N-butanol, isopropanol, tert-butanol, toluene and xylene, the mass ratio of the solvent to α -dihalogenated arylethanone is 3-10: 1, the molar ratio of α -dihalogenated arylethanone to 2, 2-dialkoxyacetaldehyde is 1: 1-3, the molar ratio of α -dihalogenated arylethanone to an acid-binding agent is 1: 2-5, and the molar ratio of α -dihalogenated arylethanone to the nitrogen source is 1: 2-16;
(2) heating to 20-100 ℃ under stirring, (if the nitrogen source is gaseous ammonia, starting to introduce ammonia), monitoring the reaction by a liquid phase, and finishing the reaction when the content of the raw material α -dihydroxy arylethanone is less than 2% (about 5 h);
(3) adding water at a constant temperature of 25 ℃, stirring for 1h to generate a large amount of solid, and filtering to obtain a crude product, wherein the mass ratio of the added water to the α -dihydroxy arylethanone is 3-10: 1;
(4) pulping the solid filter with hot water (40 ℃) for 1 hour, filtering to obtain a product 2- (dialkoxymethyl) -5-aryl-1H-imidazole (i), and drying for later use;
(5) adding the compound (i) into a mixed solution of 10% dilute sulfuric acid and methanol, stirring at 35 ℃ for two hours, neutralizing with 10% sodium hydroxide until the pH value is 7, evaporating the methanol to dryness to obtain a solid suspension, filtering to obtain 2-aldehyde-5-aryl-1H-imidazole (ii), and drying for later use; wherein the mass ratio of 10% dilute sulfuric acid to methanol is 1: 3; the mass ratio of the mixed solution of dilute sulfuric acid and methanol to the compound (i) is 3: 1;
(6) mixing 2-aldehyde-5-aryl-1H-imidazole and hydroxylamine sulfate in methanol, refluxing for 2 hours, evaporating the methanol to dryness to obtain a compound (iii), and drying for later use; wherein the molar ratio of the 2-aldehyde-5-aryl-1H-imidazole to the hydroxylamine sulfate is 1:1.1, and the mass ratio of the 2-aldehyde-5-aryl-1H-imidazole to the solvent methanol is 1: 3;
(7) suspending the compound (iii) in toluene, heating to 50 ℃, dropwise adding thionyl chloride while stirring, dropwise adding the compound for 30 minutes, then keeping the temperature for reaction for 3 hours, cooling to room temperature, dropwise adding 10% sodium hydroxide while stirring for neutralization until the pH value is 7, layering, separating a toluene layer, drying with anhydrous sodium sulfate, and evaporating the toluene to dryness to obtain a solid 2-cyano-5-aryl-1H-imidazole compound; wherein the mass ratio of the compound (iii) to toluene is 1: 3; the molar ratio of compound (iii) to thionyl chloride was 1: 1.05.
The optimized reaction temperature of the ring closing reaction is 40-50 ℃.
The optimized reaction solvent of the ring closing reaction is dimethyl sulfoxide, water, methanol, ethanol and toluene, and the mass ratio of the solvent amount to α -dihydroxy arylethanone is 3-5: 1.
The optimized mole ratio of α -dihydroxy arylethanone to nitrogen source ammonium carbonate and ammonium oxalate in the cyclization reaction is 1: 2-3, the mole ratio of α -dihydroxy arylethanone to nitrogen source ammonium acetate is 1: 4-6, and the mole ratio of α -dihydroxy arylethanone to nitrogen source ammonia and concentrated ammonia water is 1: 10-16.
The invention has the beneficial effects that:
the invention prepares the 2- (dialkoxymethyl) -5-aryl-1H-imidazole compound by reacting α -dihydroxyarylethanone which is cheap and easy to obtain with 2, 2-dimethoxyacetaldehyde, and prepares the 2-cyano-5-aryl-1H-imidazole compound by oximation, dehydration and other steps of the 2- (dialkoxymethyl) -5-aryl-1H-imidazole compound, the reaction condition is mild, the reaction temperature is less than or equal to 80 ℃, the reaction can be carried out by heating in a water bath, the operation is simple, the intermediate does not need to be purified, the yield is high, and the total yield of the four-step reaction is more than or equal to 86%.
Detailed Description
The present invention will be further described with reference to the following examples, which are intended to better understand the essential features of the present invention, and therefore should not be construed as limiting the scope of the present invention.
Example 1
α -dihydroxyacetophenone 15.2g, water 76g, 2-dimethoxyacetaldehyde 60% aqueous solution 34.7g and ammonium acetate 29.6g are sequentially added into a three-neck round-bottom flask with a thermometer, a reflux condenser tube and a stirring device, the temperature is raised to 40 ℃ with stirring, the reaction is stirred, the TLC monitors the reaction, the reaction is finished (about 5H) when the raw material α -dihydroxyacetophenone disappears, water 76g is added at 40 ℃ and stirred for 1H, a large amount of solid is generated, a crude product is obtained by filtering, the filtered solid is beaten and stirred for 1H with warm water 50g at 40 ℃, the filtered solid is filtered and dried to obtain the product 2- (dimethoxymethyl) -5-phenyl-1H-imidazole 20.0g, the yield is 94.9%, and the content is 97%.
Example 2
α -dihydroxyacetophenone 15.2g, methanol 76g, 2-dimethoxyacetaldehyde 60% water solution 34.7g and ammonium carbonate 19.2g are sequentially added into a three-neck round-bottom flask with a thermometer, a reflux condenser tube and a stirring device, the temperature is raised to 40 ℃ under stirring, the reaction is stirred, the TLC is used for monitoring the reaction, the reaction is finished when the raw material α -dihydroxyacetophenone disappears (about 4.5H), water 76g is added at 40 ℃ and stirred for 1H, a large amount of solid is generated, a crude product is obtained by filtering, the filtered solid is beaten and stirred for 1H by warm water 50g at 40 ℃, the filtered solid is filtered, and the product 2- (dimethoxymethyl) -5-phenyl-1H-imidazole 19.9g is obtained by drying, the yield is 91.2%, and the content is 96.4.
Example 3
α -dihydroxyacetophenone 15.2g, water 76g and 2, 2-dimethoxyacetaldehyde 60% aqueous solution 34.7g are sequentially added into a four-neck round-bottom flask with a thermometer, a reflux condenser and a tail gas absorption device, the temperature is raised to 40 ℃ under stirring, ammonia gas is started to be slowly introduced, the reaction is monitored by TLC, the reaction is ended when the raw material α -dihydroxyacetophenone disappears (about 5H), the amount of the introduced ammonia gas is about 19g, water 76g is added at 40 ℃ and stirred for 1H, a large amount of solid is generated, a crude product is obtained by filtration, the solid is beaten and stirred for 1H by warm water 50g at 40 ℃, filtered and dried to obtain the product 2- (dimethoxymethyl) -5-phenyl-1H-imidazole 19.6g, the yield is 90%, and the content is 96.4%.
Example 4
The procedure was carried out in substantially the same manner as in example 1, except that dimethyl sulfoxide was used as the solvent to give 18.4g of 2- (dimethoxymethyl) -5-phenyl-1H-imidazole in a yield of 84.3% and a content of 94.7%.
Example 5
The procedure was substantially the same as in example 1, except that the reaction temperature was 80 ℃ to obtain 17.9g of 2- (dimethoxymethyl) -5-phenyl-1H-imidazole in a yield of 82.2% and a content of 93.9%.
Example 6
α -dihydroxyacetophenone 27.8g, water 76g and 2, 2-dimethoxyacetaldehyde 60% aqueous solution 34.7g are sequentially added into a three-neck round-bottom flask with a thermometer, a reflux condenser tube, a stirring device and a tail gas absorption device, ammonia gas is introduced when the temperature is raised to 80 ℃ under stirring, the reaction is stirred, the TLC monitoring reaction is carried out, the reaction is finished when the raw material α -dihydroxyacetophenone disappears (about 7H), the ammonia gas is introduced for 27.5g, the temperature is lowered to 40 ℃, water 76g is added, the reaction is stirred for 1H when a large amount of solid is generated, a crude product is obtained after filtration, the filtered solid is beaten and stirred for 1H with warm water 50g at 40 ℃, the filtered solid is filtered, and the product 2- (dimethoxymethyl) -5-phenyl-1H-imidazole 19.1g is obtained after drying, the yield is 87.
Example 7
Mixing 30 g of 10% dilute sulfuric acid and 90 g of methanol, and uniformly stirring for later use; stirring and mixing 21.8g of 2- (dimethoxymethyl) -5-phenyl-1H-imidazole with 65.4 g of mixed solution of dilute sulfuric acid and methanol, stirring for two hours at 35 ℃, neutralizing with 10% sodium hydroxide until the pH value is 7, evaporating the methanol to dryness to obtain solid suspended matters, filtering and drying to obtain 16.7 g of 2-aldehyde-5-phenyl-1H-imidazole, wherein the yield is 97%, and the content is 96%;
adding 16.7 g of 2-aldehyde-5-phenyl-1H-imidazole and 8.75 g of hydroxylamine sulfate into 50g of methanol, refluxing for 2 hours, cooling to room temperature, dropwise adding a 10% sodium hydroxide solution for neutralization until the pH value is 7, evaporating the methanol to dryness to obtain a solid product, drying, weighing 17.8 g, obtaining a yield of 98%, and obtaining a content of 96.9%;
suspending 17.8 g of the compound in 53.4 g of dry toluene, heating to 50 ℃, dropwise adding 11.9 g of thionyl chloride while stirring, dropwise adding the thionyl chloride after 30 minutes, carrying out heat preservation reaction for 3 hours, cooling to room temperature, dropwise adding 10% sodium hydroxide while stirring to neutralize until the pH value is 7, layering, separating a toluene layer, drying by anhydrous sodium sulfate, evaporating the toluene to dryness to obtain a solid, drying by a vacuum oven to obtain 15.3 g of dry 2-cyano-5-phenyl-1H-imidazole, wherein the yield is 95%, and the content is 96.5%.
Claims (8)
1. A synthetic method of 2-cyano-5-aryl-1H-imidazole compounds is characterized in that a reaction chemical equation is shown as a formula (I),
firstly α -dihydroxy arylethanone and 2, 2-dialkoxyacetaldehyde undergo a cyclization reaction in a nitrogen source environment to prepare a 2- (dialkoxymethyl) -5-aryl-1H-imidazole compound, and then the 2-cyano-5-aryl-1H-imidazole compound is prepared through acidification, oximation and dehydration reaction;
wherein Ar is phenyl, substituted phenyl, furyl, thiazolyl, or naphthyl;
r is one of methyl, ethyl and isopropyl or (CH)2)2、(CH2)3A cyclic alkyl group;
the nitrogen source is one or more of ammonia gas, ammonia water, ammonium carbonate, ammonium oxalate and ammonium acetate.
2. The method for synthesizing 2-cyano-5-aryl-1H-imidazole compounds according to claim 1, which comprises the following steps:
(1) sequentially adding α -dihydroxy arylethanone, a solvent, 2-dialkoxyacetaldehyde and a liquid or solid nitrogen source into a three-neck round-bottom flask with a thermometer, a reflux condenser tube and a stirring device, and starting to introduce ammonia gas after the temperature is raised if the gaseous nitrogen source is ammonia gas;
wherein the solvent is one or more of N, N-dimethylformamide, dimethyl sulfoxide, water, methanol, ethanol, N-propanol, N-butanol, isopropanol, tert-butanol, toluene and xylene;
the mass ratio of the solvent dosage to the α -dihydroxy arylethanone is 3-10: 1;
α -dihydroxy aryl ethyl ketone and 2, 2-dialkoxyl acetaldehyde are in a molar ratio of 1: 1-3;
α -dihydroxy aryl ethyl ketone and nitrogen source in the molar ratio of 1: 2-16;
(2) heating to 20-100 ℃ under stirring, introducing ammonia gas if the temperature is a nitrogen source ammonia gas, monitoring the reaction by a liquid phase, and finishing the reaction for 8 hours when the content of the raw material α -dihydroxyarylethanone is less than 2%;
(3) adding water at a constant temperature of 25 ℃, stirring for 1h to generate a large amount of solid, and filtering to obtain a crude product, wherein the mass ratio of the added water to the α -dihydroxy arylethanone is 3-10: 1;
(4) pulping the filtered solid with hot water, stirring for 1h, filtering, and drying for later use;
(5) adding the compound i into a mixed solution of dilute sulfuric acid with the mass fraction of 10% and methanol, stirring for two hours at 35 ℃, neutralizing with 10% sodium hydroxide until the pH value is 7, evaporating the methanol to dryness to obtain solid suspended matters, filtering to obtain 2-aldehyde-5-aryl-1H-imidazole and a compound ii, and drying for later use; wherein the mass ratio of the dilute sulfuric acid with the mass fraction of 10% to the methanol is 1: 3; the mass ratio of the mixed solution of dilute sulfuric acid and methanol to the compound i is 3: 1;
(6) mixing 2-aldehyde-5-aryl-1H-imidazole and hydroxylamine sulfate with a methanol solution, refluxing for 2 hours, evaporating the methanol to dryness to obtain a compound iii, and drying for later use; wherein the molar ratio of the 2-aldehyde-5-aryl-1H-imidazole to the hydroxylamine sulfate is 1:1.1, and the mass ratio of the 2-aldehyde-5-aryl-1H-imidazole to the solvent methanol is 1: 3;
(7) suspending the compound iii in toluene, heating to 50 ℃, dropwise adding thionyl chloride while stirring, dropwise adding the mixture for 30 minutes, then carrying out heat preservation reaction for 3 hours, cooling to room temperature, dropwise adding sodium hydroxide with the mass fraction of 10% while stirring to neutralize until the pH value is 7, layering, separating a toluene layer, drying anhydrous sodium sulfate, and evaporating the toluene to dryness to obtain a solid 2-cyano-5-aryl-1H-imidazole compound; wherein the mass ratio of the compound iii to the toluene is 1: 3; the molar ratio of the compound iii to the thionyl chloride is 1: 1.05.
3. The method for synthesizing the 2-cyano-5-aryl-1H-imidazole compounds according to claim 2, wherein the optimized reaction temperature of the cyclization reaction is 40-50 ℃.
4. The method for synthesizing the 2-cyano-5-aryl-1H-imidazole compounds according to claim 2, wherein the mass ratio of the solvent dosage to the α -dihydroxy arylethanone is 3-5: 1.
5. The method for synthesizing the 2-cyano-5-aryl-1H-imidazole compounds according to claim 2, wherein the molar ratio of the α -dihydroxyarylethanone to the 2, 2-dialkoxyacetaldehyde optimized by the ring closing reaction is 1: 1-2.
6. The method for synthesizing the 2-cyano-5-aryl-1H-imidazole compounds according to claim 2, wherein the molar ratio of the α -dihydroxyarylethanone optimized for the ring-closing reaction to the nitrogen source ammonium carbonate or ammonium oxalate is 1: 2-3.
7. The method for synthesizing the 2-cyano-5-aryl-1H-imidazole compounds according to claim 2, wherein the molar ratio of the α -dihydroxyarylethanone optimized for the ring-closing reaction to the ammonium acetate is 1: 4-6.
8. The method for synthesizing the 2-cyano-5-aryl-1H-imidazole compounds according to claim 2, wherein the molar ratio of the α -dihydroxyacetophenone optimized for the ring-closing reaction to the nitrogen source ammonia gas or concentrated ammonia water is 1: 10-16.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115141593A (en) * | 2022-06-29 | 2022-10-04 | 郦玉孺 | Adhesive for formaldehyde-free plant fibers and preparation method thereof |
| CN115385860A (en) * | 2022-07-20 | 2022-11-25 | 西安近代化学研究所 | Method for synthesizing 2-cyano-5-aryl-1H-imidazole compound |
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| JPH07215946A (en) * | 1994-02-04 | 1995-08-15 | Ishihara Sangyo Kaisha Ltd | Production of 2-cyanoimidazole compound |
| CN102124002A (en) * | 2008-06-20 | 2011-07-13 | H.隆德贝克有限公司 | Novel phenylimidazole derivatives as pde10a enzyme inhibitors |
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- 2019-12-19 CN CN201911315049.5A patent/CN110981813A/en active Pending
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| JPH07215946A (en) * | 1994-02-04 | 1995-08-15 | Ishihara Sangyo Kaisha Ltd | Production of 2-cyanoimidazole compound |
| CN102124002A (en) * | 2008-06-20 | 2011-07-13 | H.隆德贝克有限公司 | Novel phenylimidazole derivatives as pde10a enzyme inhibitors |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115141593A (en) * | 2022-06-29 | 2022-10-04 | 郦玉孺 | Adhesive for formaldehyde-free plant fibers and preparation method thereof |
| CN115385860A (en) * | 2022-07-20 | 2022-11-25 | 西安近代化学研究所 | Method for synthesizing 2-cyano-5-aryl-1H-imidazole compound |
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