The photochemical behavior of the cis isomers of the three isomeric styrylpyridines and two (aminostyryl) pyridines has been investigated under aerobic and anaerobic conditions. Both 3-styrylpyridine and its 3'-amino derivative undergo highly regioselective formation of 2- azaphenanthrene products under anaerobic conditions. In the presence of oxygen, mixtures of 4-and 2-azaphenanthrene products are obtained. The formation of 2- ...
![3-[(E)-2-(4-nitrophenyl)ethenyl]pyridine Structure](https://image.chemsrc.com/caspic/256/5847-74-5.png)