Construction of pyrazolo[3,4-b]pyridines and pyrazolo[4,3-c]pyridines by ring closure of 3-acylpyridine N-oxide tosylhydrazones

被引:24
|
作者
Lominac, William J. [1 ]
D'Angelo, Megan L. [1 ]
Smith, Mark D. [2 ]
Ollison, Darius A. [1 ]
Hanna, James M., Jr. [1 ]
机构
[1] Winthrop Univ, Dept Chem Phys & Geol, Rock Hill, SC 29733 USA
[2] Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA
关键词
Pyrazolo[3,4-b]pyridines; Pyrazolo[4,3-c]pyridines; Pyridine N-oxide hydrazones; Cyclization; SYNTHASE KINASE-3 GSK-3; ONE-STEP CONVERSION; BIOLOGICAL EVALUATION; SELECTIVE INHIBITORS; POTENT INHIBITORS; DERIVATIVES; PYRIDINES; FLUORINATION; ANTAGONISTS; QUINOLINES;
D O I
10.1016/j.tetlet.2011.12.055
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
3-Acylpyridine N-oxide tosylhydrazones give good overall yields of a mixture of pyrazolo[3,4-b]pyridines and pyrazolo[4,3-c]pyridines when treated with an electrophilic additive and an amine base. (Z)-Hydrazones cyclize readily, while (E)-hydrazones fail to react under the reported conditions. The reaction takes place at room temperature, and moderate regiocontrol over the cyclization can be achieved by varying the electrophile/solvent combination. (C) 2011 Elsevier Ltd. All rights reserved.
引用
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页码:906 / 909
页数:4
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