A process for the preparation of 3-(pyridin-2-yl)imidazo[1,5-a]pyridines
The method of preparing 3-(pyridin-2-yl)imidazo[1,5-a]pyridine under mild conditions via a one-step process using an inexpensive copper salt catalyst and di-tert-butyl peroxide solves the problems of excessive raw materials and harsh conditions in existing technologies, and achieves a highly efficient and clean preparation process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING TECH UNIV
- Filing Date
- 2026-03-24
- Publication Date
- 2026-06-09
AI Technical Summary
The existing methods for preparing 3-(pyridin-2-yl)imidazo[1,5-a]pyridine require two raw materials, have harsh reaction conditions, require large amounts of reagents, cause heavy pollution, have poor atom economy, and require a variety of additives.
3-(pyridin-2-yl)imidazo[1,5-a]pyridine was prepared by a one-step process under mild conditions using a cheap copper salt catalyst such as cuprous iodide to oxidize dimethylpyridinium amine with di-tert-butyl peroxide. The reaction temperature was 100 °C, the solvent was fluorobenzene, the amount of catalyst was 0.4 times that of dimethylpyridinium amine, and the amount of oxidant was 3.0 times that of dimethylpyridinium amine.
It achieves a simple, efficient, and clean preparation process, reduces the amount of additives used, simplifies the operation process, and is suitable for laboratory pilot tests and industrial exploration.
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Figure CN122167428A_ABST
Abstract
Claims
1. A method for preparing 3-(pyridin-2-yl)imidazo[1,5-a]pyridine, a core structural unit possessing broad bioactivity, catalytic activity, and material properties, via a one-step oxidative cyclization process of dimethylpyridinium amine mediated by an inexpensive copper catalyst. Characterized by... The high-value-added heterocyclic molecule II was prepared by using dimethylpyridinium I as the starting material, inexpensive copper catalyst as the catalyst, organic peroxide as the oxidant, fluorobenzene as the reaction solvent, and mild reaction conditions. The raw material dimethylpyridineamine has structural formula I, and the heterocyclic product 3-(pyridin-2-yl)imidazo[1,5-a]pyridine has structural formula II, as shown below:
2. The method according to claim 1, characterized in that: The reaction does not require anhydrous or oxygen-free operation and uses inexpensive and readily available copper salts as the reaction medium, such as cuprous iodide, cuprous bromide, cuprous acetate, copper trifluoromethanesulfonate, copper acetylacetonate, copper chloride, copper acetate, copper bromide, and copper trifluoroacetate hydrate. Cuprous iodide is preferred, and the amount of cuprous iodide used is preferably 0.4 times that of the raw material dimethylpyridinium amine.
3. The method according to claim 1, characterized in that: The reaction temperature can be 60 ℃, 80 ℃, 100 ℃, or 120 ℃, with the preferred reaction temperature being 100 ℃.
4. The method according to claim 1, characterized in that: The reaction time can be 1 hour, 2 hours, 3 hours, 6 hours, 9 hours, or 12 hours, with the preferred reaction time being 3 hours.
5. The method according to claim 1, characterized in that: The oxidant used in this reaction can be di-tert-butyl peroxide, peroxytert-butanol, peroxytert-butyl acetate, or peroxytert-butyl benzoate, with di-tert-butyl peroxide being the preferred oxidant. The amount of the preferred oxidant is three times that of the starting material dimethylpyridinium amine.
6. The method according to claim 1, characterized in that: In the reaction, the concentration of dimethylpyridinium I is 0.17~0.5 mmol / mL, preferably 0.5 mmol / mL.