Polycyclic 1,4-dihydrobenzothieno[3,2-b]pyridine 5,5-dioxides and 4,5-dihydro-1H-indeno[1,2-b]pyridines having ester or cyano group at the position 3 of dihydropyridine ring have been synthesised. Reactivity of N-bromosuccinimide (NBS) towards polycyclic 1,4-dihydropyridine derivatives has been investigated. It has been found that 1,4-dihydrobenzothieno[3,2-b]pyridine 5,5-dioxides are easily oxidised with NBS in methanol at rt in high yields, whereas 4,5-dihydro-1H-indeno[1,2-b]pyridines in reaction with NBS in methanol are brominated at 4a position affording stable 4a-bromo-4a,5-dihydroindeno[1,2- b]pyridine-3-carboxylates or unstable 3-carbonitriles, which rapidly undergo dehydrobromination reaction leading to the corresponding 5H-indeno[1,2-b] pyridine-3-carbonitriles.
- Polycyclic 1,4-dihydropyridines
Field of Science*
- 1.4 Chemical sciences
- 3.1 Basic medicine
- 1.1. Scientific article indexed in Web of Science and/or Scopus database