Au(I)-catalyzed and iodine-mediated cyclization of enynylpyrazoles to provide pyrazolo[1,5-a]pyridines

Pyrazolo[1,5-a]pyridines and 6-iodopyrazolo[1,5-a]pyridines were synthesized by gold-catalyzed and iodine-mediated cyclization of enynylpyrazoles in good to excellent yields, respectively. The iodinated adducts were further converted to 6-arylpyrazolo[1,5-a]pyridines via Suzuki-Miyaura coupling reac...

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Bibliographic Details
Published in:Organic & biomolecular chemistry 2012-09, Vol.10 (33), p.6640-6648
Main Authors: Wu, Hung-Chou, Yang, Chia-Wen, Hwang, Long-Chih, Wu, Ming-Jung
Format: Article
Language:English
Subjects:
Catalysis
Cyclization
Gold - chemistry
Halogenation
Iodine - chemistry
Pyrazoles - chemical synthesis
Pyrazoles - chemistry
Pyridines - chemical synthesis
Pyridines - chemistry
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Summary:Pyrazolo[1,5-a]pyridines and 6-iodopyrazolo[1,5-a]pyridines were synthesized by gold-catalyzed and iodine-mediated cyclization of enynylpyrazoles in good to excellent yields, respectively. The iodinated adducts were further converted to 6-arylpyrazolo[1,5-a]pyridines via Suzuki-Miyaura coupling reaction and 6-cyanopyrazolo[1,5-a]pyridine by Ullmann condensation reaction. One of the cyclization adducts, 2-(4-fluorophenyl)pyrazolo[1,5-a]pyridine, was converted to a p38 kinase inhibitor, 2-(4-fluorophenyl)-3-(4-pyridinyl)pyrazolo[1,5-a]pyridine, in two steps.
ISSN:1477-0520
1477-0539
DOI:10.1039/c2ob25973g