Microwave-Promoted Syntheses of Pyridine Carboxamides and tert-Carboximides from Novel 6-Acetylpyridine-2-carboxylic Acid |
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| Authors: | Biyun Su Jianshe Zhao Qunzheng Zhang Wenlong Qin |
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| Affiliation: | 1. College of Chemistry and Chemical Engineering, Xi'an Shiyou University , Xi'an, China subiyun@xsyu.edu.cn;3. Department of Chemistry , Northwest University , Xi'an, China;4. College of Chemistry and Chemical Engineering, Xi'an Shiyou University , Xi'an, China;5. College of Petroleum Engineering, Xi'an Shiyou University , Xi'an, China |
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| Abstract: | A novel 6-acetylpyridine-2-carboxylic acid (4) was obtained occasionally during the synthesis of asymmetric ethyl 6-acetylpyridine-2-carboxylate (3) from 2,6-dipiclinic acid (1). Compounds 3 and 4 could transform mutually under some specific conditions. Two reactions of distinctive types occurred when they reacted with the aromatic amines as precursors, due to different functional groups on the 2-position of pyridine in the molecules of 3 and 4: one was Schiff base condensation and the other was an amidation reaction. From the latter reaction, two series of new compounds, pyridine carboxamides (5a–d) and pyridine tert-carboximides (6a–h), resulted. The relevant reaction mechanism is discussed in detail. |
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| Keywords: | 6-Acetylpyridine-2-carboxylic acid amidation reaction microwave irradiation reaction mechanism |
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