CN112079712A - Preparation method of p-vinyl salicylic acid - Google Patents
Preparation method of p-vinyl salicylic acid Download PDFInfo
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- CN112079712A CN112079712A CN202010987683.XA CN202010987683A CN112079712A CN 112079712 A CN112079712 A CN 112079712A CN 202010987683 A CN202010987683 A CN 202010987683A CN 112079712 A CN112079712 A CN 112079712A
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- C07C51/347—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups
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- C07C51/363—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups by introduction of halogen; by substitution of halogen atoms by other halogen atoms
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Abstract
The invention discloses a preparation method of p-vinyl salicylic acid, which comprises the following steps: (1) diazotizing para-aminosalicylic acid and nitrous acid in water to generate a diazotized intermediate, and then adding metal iodide to perform an iodination reaction to generate para-iodosalicylic acid; (2) reacting p-iodosalicylic acid with a compound of formula (a)
Reacting in a mixed solution of methanol and water to generate p-vinyl salicylic acid; in the formula (a), R1、R2And R3Are each independently selected from C1‑6Alkyl radical, C1‑6Alkoxy, phenoxy, CH3(CH2)mO(CH2)nO-, m is 0, 1, 2, 3, 4, 5 or 6, n is 1, 2, 3, 4, 5 or 6; the method can obtain ideal yield and purity under mild and simple reaction conditionsThe occurrence of side reactions is reduced, and simultaneously, the adopted reagent raw materials are cheaper, easily obtained, safe and environment-friendly, and are suitable for industrial large-scale production.
Description
Technical Field
The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of p-vinyl salicylic acid.
Background
P-vinyl salicylic acid (4-ethyl-2-hydroxysalicylic acid, or 4-vinyl salicylic acid, CAS No. 71534-98-0, molecular formula C)9H8O3) The structural formula is as follows:
the p-vinyl salicylic acid is an important synthetic intermediate, can be used as a raw material for synthesizing a novel photosensitizer which has potential application value in the aspect of manufacturing dye-sensitized solar cells (Journal of Nanoscience and Nanotechnology 2016,16,4880-4885), and can also be used as a raw material for synthesizing a novel cholinergic muscarinic M1 receptor modulator, and the M1 receptor modulator can be used as a medicine for preventing and treating Alzheimer disease, schizophrenia, sleep disorder, Parkinson disease and the like (WO2016208775A 1). Further, p-vinyl salicylic acid can also be used as a synthetic charge control agent, which is one of the main components of color printing toner (JP 2013125162).
At present, few reports about the synthesis process of the ethylene salicylic acid are reported. There is a known patent report (WO2014/039434a1) which is a method for synthesizing p-vinyl salicylic acid by Suzuki coupling reaction of methyl 2-hydroxy-4-iodobenzoate and a vinyl boronic anhydride pyridine complex, specifically as follows:
however, the method uses expensive 2-hydroxy-4-iodobenzoic acid methyl ester and vinyl boron anhydride pyridine complex, and uses Pd (PPh) as catalyst3)4The catalyst is easy to be oxidized and inactivated in the air, and is not beneficial to large-scale application of industrialization.
Disclosure of Invention
The technical problem to be solved by the invention is to overcome the defects of the prior art, and provide an improved preparation method of p-vinyl salicylic acid, which can obtain ideal yield and purity under mild and simple reaction conditions, reduces the occurrence of side reactions, and simultaneously adopts cheap and easily obtained reagent raw materials, is safe and environment-friendly, and is suitable for industrial large-scale production.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a preparation method of p-vinyl salicylic acid comprises the following steps:
(1) diazotizing para-aminosalicylic acid and nitrous acid in water to generate a diazotized intermediate, and then adding metal iodide to perform an iodination reaction to generate para-iodosalicylic acid;
(2) reacting the p-iodosalicylic acid with a compound shown as a formula (a) in a mixed solution of methanol and water to generate the p-vinyl salicylic acid;
in the formula (a), R1、R2And R3Are each independently selected from C1-6Alkyl radical, C1-6Alkoxy, phenoxy, CH3(CH2)mO(CH2)nO-, m is 0, 1, 2, 3, 4, 5 or 6, and n is 1, 2, 3, 4, 5 or 6.
According to some preferred and specific aspects of the present invention, in step (1), the nitrous acid is generated by reacting a nitrite salt with hydrochloric acid and/or sulfuric acid, the nitrite salt including sodium nitrite, potassium nitrite, and lithium nitrite.
According to some preferred aspects of the invention, the specific embodiment in step (1) comprises: mixing the p-aminosalicylic acid with the hydrochloric acid and/or the sulfuric acid, then adding the nitrite, reacting, and then adding the metal iodide to perform an iodination reaction.
According to some preferred aspects of the present invention, in step (1), the molar ratio of the p-aminosalicylic acid, the hydrochloric acid and/or sulfuric acid, the nitrite, and the metal iodide fed is 1:1-2:1-2: 1-2.
According to some preferred aspects of the present invention, in step (1), the diazotization reaction is controlled to be carried out at 0 to 5 ℃.
According to some preferred aspects of the present invention, in the step (1), the iodination is controlled to be performed at 15 to 40 ℃. More preferably, in the step (1), the iodination is controlled to be performed at 20 to 30 ℃. According to a specific aspect of the present invention, in the step (1), the iodination reaction is performed at room temperature.
According to some preferred aspects of the present invention, in step (1), the metal iodide is a combination of one or more selected from the group consisting of potassium iodide (KI), sodium iodide (NaI), and copper iodide (CuI).
According to some preferred aspects of the invention, in step (2), the reaction is reacted in the presence of a base and a palladium catalyst.
According to some preferred aspects of the present invention, in the step (2), the base is a combination of one or more selected from sodium carbonate, sodium hydroxide, sodium methoxide, and sodium tert-butoxide.
According to some preferred aspects of the present invention, in the step (2), the palladium catalyst is selected from Pd (PPh)3)Cl2、Pd2(dba)3、Pd(OAc)2And Pd/C.
According to some preferred aspects of the present invention, in the step (2), the molar ratio of the palladium catalyst, the base, the compound represented by the formula (a), and the p-aminosalicylic acid is fed in a range of 0.01 to 0.05:3 to 5:1 to 3: 1.
According to some preferred aspects of the present invention, in the step (2), the reaction is performed at a temperature controlled to be 80 to 120 ℃. More preferably, in the step (2), the reaction is carried out at a temperature of 90 to 120 ℃. Further preferably, in the step (2), the reaction is carried out at a temperature of 90 to 110 ℃. According to a specific aspect of the present invention, in the step (2), the reaction temperature is controlled to be 100 ℃.
According to some preferred aspects of the present invention, in the step (2), a volume ratio of the methanol to the water in the mixed solution is 0.5 to 1: 1.
According to some preferred aspects of the present invention, in step (2), R1、R2And R3Each independently selected from methyl, ethyl, propyl, methoxy, ethoxy, propoxy, phenoxy, CH3O(CH2)2O-、CH3CH2O(CH2)3O-、CH3O(CH2)3O-。
According to some preferred and specific aspects of the present invention, in the step (2), the compound represented by the formula (a) is selected from the group consisting of trimethylvinylsilane, triethoxyvinylsilane, triphenoxyvinylsilane, and tris (2-methoxyethoxy) vinylsilane.
According to some preferred aspects of the present invention, the preparation method adopts a one-pot method to prepare the p-vinyl salicylic acid.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages:
the invention takes para-aminosalicylic acid as an initial raw material, diazotizes the para-aminosalicylic acid, and then performs iodination reaction to obtain para-iodosalicylic acid, so that the para-iodosalicylic acid can react with the specific vinyl silicon reagent shown in the formula (a) to obtain the para-vinyl salicylic acid, and the reaction of the para-iodosalicylic acid and the specific vinyl silicon reagent (with low price) shown in the formula (a) is reacted in a mixed solution of methanol and water, so that not only is the more ideal yield and purity obtained, but also a polar aprotic solvent which is high in toxicity and difficult to post-treat is avoided, and the post-treatment difficulty is reduced; meanwhile, the preparation process can be synthesized by a one-pot method, separation is not needed in the middle process, the operation process is greatly simplified, and industrial large-scale production is facilitated.
Drawings
FIG. 1 shows the results obtained for the end product of example 11HNMR spectrogram.
Detailed Description
The above-described scheme is further illustrated below with reference to specific examples; it is to be understood that these embodiments are provided to illustrate the general principles, essential features and advantages of the present invention, and the present invention is not limited in scope by the following embodiments; the implementation conditions used in the examples can be further adjusted according to specific requirements, and the implementation conditions not indicated are generally the conditions in routine experiments. In the following, unless otherwise specified, "%" means mass percent.
In the following, all starting materials are either commercially available or prepared by conventional methods in the art, unless otherwise specified. In the following examples, the preparation routes used are as follows:
example 1
5mmol (765mg) of para-aminosalicylic acid and 7.5mmol (0.65mL) of 36% concentrated hydrochloric acid were stirred at room temperature for 15min, after cooling to 0 ℃ 7.5mmol (518mg sodium nitrite dissolved in 2.2mL water) of aqueous sodium nitrite solution were slowly added dropwise with continued stirring for 15min, followed by the addition of 7.5mmol (1.43g) of CuI in portions with continued stirring at room temperature for 30min to give para-iodosalicylic acid.
After the reaction, the reaction solution was transferred to a hydrothermal reaction kettle without any post-treatment, and 17.5mmol (700mg) of NaOH and 0.05mmol (46mg) of Pd were added to the reaction mixture2(dba)310mmol (1.9g) triethoxyvinylsilane and 5mL methanol, and the reaction was continued for 10h by heating to 100 ℃. And (3) after cooling, adding 1M HCl to adjust the pH value to be neutral, extracting and separating liquid, taking an organic phase for drying, removing the organic phase by rotary evaporation, and performing silica gel column chromatography to obtain the p-vinyl salicylic acid, wherein the yield is 65% (0.53g) and the purity is 95.8%. And (3) measuring:1HNMR(500MHz,DMSO-d6)5.41(d,J＝15Hz,1H),5.96(d,J＝20Hz,1H),6.71(dd,J＝15,10Hz,1H),7.03-7.05(m,2H),7.75(d,J＝10Hz,1H),12.28(br,1H)。
example 2
5mmol (765mg) of para-aminosalicylic acid and 7.5mmol (0.65mL) of 36% concentrated hydrochloric acid are stirred at room temperature for 15min, after cooling to 0 ℃, 7.5mmol (518mg sodium nitrite dissolved in 2.2mL water) of sodium nitrite aqueous solution is slowly dropped and stirring is continued for 15min, then 7.5mmol (1.25g KI dissolved in 2.2mL water) of KI aqueous solution is slowly dropped and stirring is continued for 30min at room temperature, and para-iodosalicylic acid is generated.
After the reaction, the reaction solution was transferred to a hydrothermal reaction kettle without any post-treatment, and 17.5mmol (700mg) of NaOH and 0.05mmol (46mg) of Pd were added to the reaction mixture2(dba)310mmol (1.9g) triethoxyvinylsilane and 5mL methanol, and the reaction was continued for 10h by heating to 100 ℃. And (3) cooling, adding 1M HCl to adjust the pH value to be neutral, extracting and separating liquid, taking an organic phase for drying, removing the organic phase by rotary evaporation, and performing silica gel column chromatography to obtain the p-vinyl salicylic acid with the yield of 59% (0.48g) and the purity of 96.3%.
Example 3
5mmol (765mg) of para-aminosalicylic acid and 7.5mmol (0.65mL) of 36% concentrated hydrochloric acid are stirred at room temperature for 15min, after cooling to 0 ℃, 7.5mmol (518mg sodium nitrite dissolved in 2.2mL water) of sodium nitrite aqueous solution is slowly dropped and stirring is continued for 15min, then 7.5mmol (1.25g KI dissolved in 2.2mL water) of KI aqueous solution is slowly dropped and stirring is continued for 30min at room temperature, and para-iodosalicylic acid is generated.
After the reaction, the reaction mixture was transferred to a hydrothermal reaction vessel without any post-treatment, and 17.5mmol (700mg) of NaOH, 0.05mmol (265mg) of 5% Pd/C, 10mmol (1.9g) of triethoxyvinylsilane, and 5mL of methanol were added to the reaction mixture, and the reaction was continued for 10 hours while the temperature was raised to 100 ℃. And (3) cooling, adding 1M HCl to adjust the pH value to be neutral, extracting and separating liquid, taking an organic phase for drying, removing the organic phase by rotary evaporation, and performing silica gel column chromatography to obtain the p-vinyl salicylic acid, wherein the yield is 48% (0.39g) and the purity is 95.9%.
Comparative example 1
5mmol (765mg) of para-aminosalicylic acid and 7.mmol (0.65mL) of 36% concentrated hydrochloric acid were stirred at room temperature for 15min, after cooling to 0 ℃ 7.5mmol (518mg sodium nitrite dissolved in 2.2mL water) of aqueous sodium nitrite solution was slowly added dropwise and stirring was continued for 15min, followed by 7.5mmol (1.25g KI dissolved in 2.2mL water) of aqueous KI solution being slowly added dropwise and stirring was continued for 30min at room temperature to give para-iodosalicylic acid.
After the reaction, the reaction mixture was transferred to a hydrothermal reaction vessel without any post-treatment, and 17.5mmol (700mg) of NaOH, 0.05mmol (46mg) of Pd2(dba)3, 10mmol (1.9g) of triethoxyvinylsilane, and 5mL of methanol were added to the reaction mixture, and the reaction was continued for 10 hours while the temperature was raised to 70 ℃. And (3) after cooling, adding 1M HCl to adjust the pH value to be neutral, extracting and separating liquid, taking an organic phase for drying, removing the organic phase by rotary evaporation, and detecting no target product by gas chromatography.
The above embodiments are merely illustrative of the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and implement the invention, and not to limit the scope of the invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.
Claims (10)
1. A preparation method of p-vinyl salicylic acid is characterized by comprising the following steps:
(1) diazotizing para-aminosalicylic acid and nitrous acid in water to generate a diazotized intermediate, and then adding metal iodide to perform an iodination reaction to generate para-iodosalicylic acid;
(2) reacting the p-iodosalicylic acid with a compound shown as a formula (a) in a mixed solution of methanol and water to generate the p-vinyl salicylic acid;
in the formula (a), R1、R2And R3Are each independently selected from C1-6Alkyl radical, C1-6Alkoxy, phenoxy, CH3(CH2)mO(CH2)nO-, m is 0, 1, 2, 3, 4, 5 or 6, and n is 1, 2, 3, 4, 5 or 6.
2. The method for preparing p-vinylsalicylic acid according to claim 1, wherein in step (1), the nitrous acid is generated by reacting nitrite salts comprising sodium nitrite, potassium nitrite and lithium nitrite with hydrochloric acid and/or sulfuric acid.
3. The method for preparing p-vinyl salicylic acid according to claim 2, wherein the specific embodiment in the step (1) comprises: mixing the p-aminosalicylic acid with the hydrochloric acid and/or the sulfuric acid, then adding the nitrite, reacting, and then adding the metal iodide to perform an iodination reaction.
4. The method for preparing p-vinyl salicylic acid according to claim 3, wherein in step (1), the molar ratio of the p-aminosalicylic acid, the hydrochloric acid and/or sulfuric acid, the nitrite and the metal iodide is 1:1-2:1-2: 1-2.
5. The process for preparing p-vinyl salicylic acid according to claim 1, wherein in the step (1), the diazotization reaction is controlled to be carried out at 0-5 ℃; and/or, in the step (1), the iodination reaction is controlled to be carried out at 15-40 ℃; and/or, in the step (1), the metal iodide is one or more of potassium iodide, sodium iodide and cuprous iodide.
6. The method for producing p-vinylsalicylic acid according to claim 1, wherein in the step (2), the reaction is carried out in the presence of a base which is a combination of one or more selected from sodium carbonate, sodium hydroxide, sodium methoxide and sodium tert-butoxide, and a palladium catalyst which is selected from Pd (PPh)3)Cl2、Pd2(dba)3、Pd(OAc)2And Pd/C.
7. The method for preparing p-vinylsalicylic acid according to claim 6, wherein in the step (2), the molar ratio of the palladium catalyst, the base, the compound represented by the formula (a) and the p-aminosalicylic acid is 0.01-0.05:3-5:1-3: 1.
8. The method for preparing p-vinyl salicylic acid according to claim 1, characterized in that in the step (2), the reaction temperature is controlled to be 80-120 ℃; and/or in the step (2), the volume ratio of the methanol to the water in the mixed solution is 0.5-1: 1.
9. The process for producing p-vinylsalicylic acid according to claim 1, wherein in the step (2), R is1、R2And R3Each independently selected from methyl, ethyl, propyl, methoxy, ethoxy, propoxy, phenoxy, CH3O(CH2)2O-、CH3CH2O(CH2)3O-、CH3O(CH2)3O-。
10. The method for preparing p-vinyl salicylic acid according to claim 1, wherein the method for preparing p-vinyl salicylic acid adopts a one-pot method.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1500772A (en) * | 2002-11-12 | 2004-06-02 | 上海三维制药有限公司 | Synthetic method of 4-acetoxy-2-ethoxy ethyl benzoate |
| CN104619695A (en) * | 2012-09-07 | 2015-05-13 | 勃林格殷格翰国际有限公司 | Alkoxy pyrazoles as soluble guanylate cyclase activators |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1500772A (en) * | 2002-11-12 | 2004-06-02 | 上海三维制药有限公司 | Synthetic method of 4-acetoxy-2-ethoxy ethyl benzoate |
| CN104619695A (en) * | 2012-09-07 | 2015-05-13 | 勃林格殷格翰国际有限公司 | Alkoxy pyrazoles as soluble guanylate cyclase activators |
Non-Patent Citations (2)
| Title |
|---|
| EMILIO ALACID等: "Aqueous Sodium Hydroxide Promoted Cross-Coupling Reactions of Alkenyltrialkoxysilanes under Ligand-Free Conditions", 《JOURNAL OF ORGANIC CHEMISTRY》 * |
| TRAFICANTE, CARLA I.等: "Chemoselective and Sequential Palladium-Catalyzed Couplings for the Generation of Stilbene Libraries via Immobilized Substrates", 《ACS COMBINATORIAL SCIENCE》 * |
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