TY - JOUR
T1 - Contrasting behaviour of NBS towards 1,4-dihydrobenzothieno[3,2-b]pyridine 5,5-dioxides and 4,5-dihydro-1H-indeno[1,2-b]pyridines
AU - Cekavicus, Brigita
AU - Vigante, Brigita
AU - Rucins, Martins
AU - Birkmane, Kintija
AU - Petrova, Marina
AU - Belyakov, Sergey
AU - Zuka, Liga
AU - Plotniece, Aiva
AU - Pajuste, Karlis
AU - Gosteva, Marina
AU - Sobolev, Arkadij
N1 - Funding Information:
This research work was supported by European Regional Development Fund (ERDF) project No. 2010/2DP/2.1.1.1.0/10/APIA/VIAA/072 and Grant of Latvian Council of Science No. 09.1566 . Authors are indebted to professor Gunars Duburs for his helpful suggestions during the course of investigation.
PY - 2013/7/1
Y1 - 2013/7/1
N2 - 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.
AB - 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.
KW - Bromination
KW - Cyclisation
KW - N-Bromosuccinimide
KW - Oxidation
KW - Polycyclic 1,4-dihydropyridines
UR - http://www.scopus.com/inward/record.url?scp=84878236842&partnerID=8YFLogxK
U2 - 10.1016/j.tet.2013.04.060
DO - 10.1016/j.tet.2013.04.060
M3 - Article
AN - SCOPUS:84878236842
SN - 0040-4020
VL - 69
SP - 5550
EP - 5557
JO - Tetrahedron
JF - Tetrahedron
IS - 26
ER -