Abstract Treatment of the N-oxide 1a of thieno [2, 3-b] pyridine (1) with either (a) acetic anhydride and ethyl cyanoacetate or (b) benzoyl chloride and an enamine of cyclohexanone (Hamana reactions) serves to introduce a C-substituent at the 4-position of 1. In case (a) one obtains a yellow, isolable vinylogous N-ylide 5 (23% yield), which undergoes facile transformation into ethyl 2-(4-thieno [2, 3-b] pyridyl) cyanoacetate (1e)(88–93%). Acetic ...
![thieno[2,3-b]pyridine 7-oxide Structure](https://image.chemsrc.com/caspic/435/25557-50-0.png)
![2-thieno[2,3-b]pyridin-4-ylcyclohexan-1-one Structure](https://image.chemsrc.com/caspic/163/94319-43-4.png)
