Regioselective formylation of pyrazolo[3,4-b]pyridine and pyrazolo[1,5-a]pyrimidine systems using Vilsmeier–Haack conditions

doi:10.1016/j.tetlet.2008.02.166

Tetrahedron Letters

Volume 49, Issue 17, 21 April 2008, Pages 2689-2691

https://doi.org/10.1016/j.tetlet.2008.02.166 Get rights and content

Abstract

Regioselective formylation behavior has been found in the reaction of pyrazolo[3,4-b]pyridines and pyrazolo[1,5-a]pyrimidines via Vilsmeier–Haack conditions. While the 4,5- and 6,7-dihydro derivatives afforded pyrazolo[3,4-b]pyridine-5-carbaldehydes and 4,7-dihydropyrazolo[1,5-a]pyrimidine-3,6-dicarbaldehydes, respectively, the aromatic analogs rendered the pyrazolo[1,5-a]pyrimidine-3-carbaldehyde only, and no reaction took place at the pyrazolopyridine derivatives.

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Acknowledgments

The authors are grateful to COLCIENCIAS, to Universidad del Valle, to the Spanish ‘Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía’, and ‘Servicios Técnicos de Investigación’ of ‘Universidad de Jaén’ for financial support.

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Regioselective formylation of pyrazolo[3,4-b]pyridine and pyrazolo[1,5-a]pyrimidine systems using Vilsmeier–Haack conditions

Abstract

Graphical abstract

Section snippets

Acknowledgments

Chem. Heterocycl. Compd.

Chem. Heterocycl. Comp.

J. Heterocyclic Chem.

Khim. Geterosikl. Soedin.

Khim. Geterosikl. Soedin.

J. Heterocyclic Chem.

J. Heterocyclic Chem.

Targets Heterocycl. Syst.

J. Med. Chem.

Bioorg. Med. Chem. Lett.

Adv. Heterocycl. Chem.

Adv. Heterocycl. Chem.

Adv. Heterocycl. Chem.