The 2-aryl-3-methylpyridines 7a-c were obtained in good yield by the addition of the corresponding aryllithium to 2-fluoro-3-methylpyridine. Permanganate oxidation provided the 2-aryl-3-pyridinecarboxylic acids 8a-c which were cyclized to 5H-indeno [l, 2-b] pyridin-5- ones 6a-c in hot polyphosphoric acid. The 5H-indeno [1, 2-b] pyridines 5a-c were readily obtained from the ketones 6a-c by treatment with hydrazine in hot diethylene glycol.
![7-fluoro-5H-indeno[1,2-b]pyridin-5-one结构式](https://www.chemsrc.com/extcaspic/243/101419-80-1.png)
![7-fluoro-5H-indeno[1,2-b]pyridine结构式](https://image.chemsrc.com/caspic/182/97677-23-1.png)
![7-chloro-5H-Indeno[1,2-b]pyridin-5-one结构式](https://image.chemsrc.com/caspic/205/101419-81-2.png)
![5H-茚并[1,2-b]吡啶结构式](https://image.chemsrc.com/caspic/095/244-99-5.png)