jo502096t_si_002.cif (19.94 kB)
Four-Component Bicyclization Approaches to Skeletally Diverse Pyrazolo[3,4‑b]pyridine Derivatives
dataset
posted on 2015-12-17, 05:57 authored by Xing-Jun Tu, Wen-Juan Hao, Qin Ye, Shuang-Shuang Wang, Bo Jiang, Guigen Li, Shu-Jiang TuA novel four-component bicyclization
strategy has been established,
allowing a flexible and practical approach to 37 examples of multicyclic
pyrazolo[3,4-b]pyridines from low-cost and readily
accessible arylglyoxals, pyrazol-5-amines, aromatic amines, 4-hydroxy-6-methyl-2H-pyran-2-one, and cyclohexane-1,3-diones. The polysubstituted
cyclopenta[d]pyrazolo[3,4-b]pyridines
were stereoselectively synthesized through a microwave-assisted special
[3+2+1]/[3+2] bicyclization with good control of the spatial configuration
of exocyclic double bonds. The novel [3+2+1]/[2+2+1] bicyclization
resulted in 17 examples of unreported pyrazolo[3,4-b]pyrrolo[4,3,2-de]quinolones. Reasonable mechanisms
for forming two new types of multicyclic pyrazolo[3,4-b]pyridines are also proposed.