- 作者: Chun-Yen Chiua,b, Chao-Nan Kuoa, Wen-Fa Kuoa and Mou-Yung Yeha
- 中文摘要: 2-Aryl-2H-[1,2,4]triazolo[4,3-a]pyridin-3-ones 4 were synthesized by cycloaddition of α-chloroformylarylhydrazines 7 with pyridines 1. The inductive and mesomeric effects of substituents on pyridines were also investigated in this study. In reactions of 3-substituted pyridines bearing a π-electron-donating substituent, the ortho site, C(2), of the pyridine ring is more favored for cycloaddition than the para site, C(6). As the substituent is a s-electron-donating group, the cycloaddition only occurs on the ortho position. For reactions of 2-substituted pyridines, however, cycloadditions were controlled solely by inductive effect, regardless of mesomeric effect. Only when the substituent is an electron-donating group, would the cycloaddition proceed to afford expected cycloadducts. Furthermore, it is found that the inductive effect plays a more important role than the steric effect for reactions using 2-substituted pyridines.
- 英文摘要: --
- 中文關鍵字: --
- 英文關鍵字: --