Preparation method of 3, 3 '-(1, 3, 4-oxadiazole-2, 5-methylene) bipyridine
By employing a simplified synthesis process and utilizing an alcohol solvent and hydrazine hydrate at room temperature, the problems of high catalyst cost and complex equipment in existing technologies have been solved, achieving the preparation of 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine with high yield and high purity, which is suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHANGJIAGANG GUOTAI HUARONG NEW CHEM MATERIALS CO LTD
- Filing Date
- 2024-10-19
- Publication Date
- 2026-04-21
AI Technical Summary
Existing methods for synthesizing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine suffer from high catalyst costs, demanding equipment requirements, and complex post-processing, making industrial-scale production difficult.
Using 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene as raw material, an alcohol solvent and 50% hydrazine hydrate were used to stir the reaction at room temperature. The reaction was then filtered, washed with water, dissolved, and a second organic solvent was slowly added dropwise and filtered again. Finally, the mixture was washed with a mixed solvent and dried by rotary evaporation, which simplified the process.
It achieves a low-cost, easy-to-control synthesis process, improves yield and purity, reduces production costs, and is suitable for industrial production.
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Figure CN121895302A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical synthesis technology, specifically to a method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine. Background Technology
[0002] 1,3,4-Oxadiazole materials and their derivatives have attracted widespread attention due to their unique framework and chemical / physical properties, as well as their special application potential in industrial, agricultural and medical fields.
[0003] Currently, there are two main methods for synthesizing 3,3'-(1,3,4-oxadiazol-2,5-methylene)dipyridine. The first method (see reference 1) uses MOF material as a catalyst, and 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene and water as raw materials, stirred at room temperature. The main drawback of this method is the high cost and difficulty in obtaining the catalyst.
[0004] Document 1: Goswami, Soumyabrata; Jena, Himanshu Sekhar; Konar, Sanjit Inorganic Chemistry, 2014, 53, 7071–7073.
[0005] The second preparation method (see reference 2) uses nicotinic acid, phosphorus oxychloride, and hydrazine hydrate as raw materials, and involves reflux stirring. The main disadvantages of this method are that it requires sophisticated equipment and has complicated post-processing.
[0006] Document 2: Bentiss, Fouad; Lagrenee, Michel Journal of Heterocyclic Chemistry, 1999, 36, 1029–1032. Summary of the Invention
[0007] The purpose of this invention is to provide a method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine that uses readily available raw materials, has a simple preparation process, high yield, and is suitable for industrial production.
[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing 3,3'-(1,3,4-oxadiazol-2,5-methylene)dipyridine, comprising the following steps: 1. Dissolving 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene in an alcohol solvent to form a clear purple solution, adding 50% (w / w) hydrazine hydrate and stirring at room temperature, resulting in the precipitation of a solid, wherein the alcohol solvent is methanol or ethanol; 2. Filtering and washing with water to obtain a pale yellow solid; dissolving in a first organic solvent, and slowly adding a second organic solvent, resulting in the precipitation of a white solid, filtering, washing with a washing solvent, and drying the filtered solid by rotary evaporation to obtain a pure white solid.
[0009] The above reaction formula is as follows: .
[0010] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the mass ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to alcohol solvent in the first step is 1:(3-5).
[0011] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazol-2,5-methylene)dipyridine, in the first step, the molar ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to 50% hydrazine hydrate is 1:(15-20).
[0012] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the stirring time in the first step is 3h to 5h.
[0013] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the first organic solvent in the second step is dichloromethane or chloroform.
[0014] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the mass ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to the first organic solvent in the second step is 1:(5-10).
[0015] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the second organic solvent in the second step is n-hexane or petroleum ether.
[0016] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the mass ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to the second organic solvent in the second step is 1:(10-20).
[0017] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the washing solvent is a mixture of dichloromethane and n-hexane.
[0018] Furthermore, in the aforementioned method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, the volume ratio of dichloromethane to n-hexane in the mixed solvent is 1:10~20.
[0019] The advantages of this invention are: 1. The process route is very simple, the reaction conditions are mild and easy to control, the purification difficulty is low, the by-products are few, the yield is high, and the purity is high. 2. The reaction time is short, the raw materials can all be purchased directly, the production cost is greatly reduced, and it is suitable for industrial production. Attached Figure Description
[0020] Figure 1 This is the 1H NMR spectrum of the product in Example 1.
[0021] Figure 2 This is the carbon NMR spectrum of the product in Example 1. Detailed Implementation
[0022] The preparation method of 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to the present invention will be described in detail below through specific embodiments.
[0023] Example 1: I. 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 300g of ethanol, resulting in a clear purple solution. 636g of 50% (w / w) hydrazine hydrate was added and stirred at room temperature for 3 hours, resulting in the precipitation of a solid. II. The solution was filtered and washed with water to obtain a pale yellow solid. 500g of dichloromethane was added to dissolve the solid, and 1000g of n-hexane was slowly added dropwise, resulting in the precipitation of a white solid. The solution was filtered and washed with a dichloromethane-n-hexane mixed solvent (volume ratio 1:10). The filtered solid was dried by rotary evaporation to obtain 78g of a pure white solid (yield: 83%, purity: 99.2%). The 1H NMR spectrum of the product is shown below. Figure 1 As shown, see the carbon NMR spectrum. Figure 2 As shown.
[0024] Example 2: 1. 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 300g of methanol to form a clear purple solution. 848g of 50% hydrazine hydrate was added and stirred at room temperature for 3 hours, resulting in the precipitation of a solid. 2. The solution was filtered and washed with water to obtain a pale yellow solid. 700g of dichloromethane was added to dissolve the solid, and 1500g of n-hexane was slowly added dropwise, resulting in the precipitation of a white solid. The solution was filtered and washed with a dichloromethane-n-hexane mixed solvent (volume ratio 1:15). The filtered solid was dried by rotary evaporation to obtain 80g of a pure white solid (yield: 85%, purity: 99.1%).
[0025] Example 3: 1. 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 500g of ethanol to form a clear purple solution. 636g of 50% hydrazine hydrate was added and stirred at room temperature for 4 hours, resulting in the precipitation of a solid. 2. The solution was filtered and washed with water to obtain a pale yellow solid. 900g of chloroform was added to dissolve the solid, and 1800g of n-hexane was slowly added dropwise, resulting in the precipitation of a white solid. The solution was filtered and washed with a dichloromethane-n-hexane mixed solvent (volume ratio 1:20). The filtered solid was dried by rotary evaporation to obtain 68g of a white solid of pure product (yield: 72%, purity: 99.2%).
[0026] Example 4: 1. 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 300g of ethanol to form a clear purple solution. 636g of 50% hydrazine hydrate was added and stirred at room temperature for 3 hours, resulting in the precipitation of a solid. 2. The solution was filtered and washed with water to obtain a pale yellow solid. 600g of dichloromethane was added to dissolve the solid, and 1500g of petroleum ether was slowly added dropwise, resulting in the precipitation of a white solid. The solution was filtered and washed with a dichloromethane-n-hexane mixed solvent (volume ratio 1:10). The filtered solid was dried by rotary evaporation to obtain 78g of a pure white solid (yield: 82%, purity: 99.2%).
[0027] Example 5: 1. 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 500g of methanol to form a clear purple solution. 636g of 50% (w / w) hydrazine hydrate was added and stirred at room temperature for 5 hours, resulting in the precipitation of a solid. 2. The solution was filtered and washed with water to obtain a pale yellow solid. 1000g of chloroform was added to dissolve the solid, and 2000g of petroleum ether was slowly added dropwise, resulting in the precipitation of a white solid. The solution was filtered and washed with a mixed solvent of dichloromethane-n-hexane (volume ratio 1:10). The filtered solid was dried by rotary evaporation to obtain 66g of a pure white solid (yield: 70%, purity: 99.2%).
[0028] Comparative Example 1: 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 1500g of methanol to form a clear purple solution. 636g of 50% hydrazine hydrate was added and stirred at room temperature for 5h. No solid precipitated.
[0029] Comparative Example 1 shows that an excessive proportion of organic solvent will prevent the product from precipitating.
[0030] Comparative Example 2: 1. 100g of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene was dissolved in 500g of methanol to form a clear purple solution. 636g of deionized water was added and stirred at room temperature for 5h. No solid precipitated.
[0031] Comparative Example 2 shows that no product is generated in the absence of anhydrous hydrazine.
[0032] The advantages of this invention are: 1. The process route is very simple, the reaction conditions are mild and easy to control, the purification difficulty is low, the by-products are few, the yield is high, and the purity is high. 2. The reaction time is short, the raw materials can all be purchased directly, the production cost is greatly reduced, and it is suitable for industrial production.
Claims
A method for preparing 1,3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine, comprising the following steps:
1. Dissolve 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene in an alcohol solvent to form a clear purple solution. Add 50% (w / w) hydrazine hydrate and stir at room temperature; a solid precipitates out. The alcohol solvent is methanol or ethanol.
2. Filter and wash with water to obtain a pale yellow solid. Dissolve the solid in a first organic solvent, and slowly add a second organic solvent; a white solid precipitates out. Filter, wash with a washing solvent, and dry the filtrate by rotary evaporation to obtain a pure white solid.
2. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 1, characterized in that: In the first step, the mass ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to alcohol solvent is 1:(3-5).
3. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 1, characterized in that: In the first step, the molar ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to 50% hydrazine hydrate is 1:(15-20).
4. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 1, characterized in that: The stirring time in the first step is 3 to 5 hours.
5. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 1, characterized in that: In the second step, the first organic solvent is either dichloromethane or chloroform.
6. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 5, characterized in that: In the second step, the mass ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to the first organic solvent is 1:(5-10).
7. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 5, characterized in that: In the second step, the second organic solvent is either n-hexane or petroleum ether.
8. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 7, characterized in that: In the second step, the mass ratio of 3,6-bis(3-pyridyl)-1,2,4,5-tetraazabenzene to the second organic solvent is 1:(10-20).
9. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 7, characterized in that: The washing solvent is a mixture of dichloromethane and n-hexane.
10. The method for preparing 3,3'-(1,3,4-oxadiazole-2,5-methylene)dipyridine according to claim 9, characterized in that: The volume ratio of dichloromethane to n-hexane in the mixed solvent is 1:10~20.