Straightforward and Efficient Protocol for the Synthesis of Pyrazolo [4,3-b]pyridines and Indazoles

Straightforward and Efficient Protocol for the Synthesis of Pyrazolo [4,3-b]pyridines and Indazoles Full article

Journal

International Journal of Molecular Sciences
ISSN: 1661-6596 , E-ISSN: 1422-0067

Output data

Year: 2023, Volume: 24, Number: 2, Article number : 1758, Pages count : DOI: 10.3390/ijms24021758

Authors

Nikol’skiy Vladislav V. ¹ , Minyaev Mikhail E. ¹ , Bastrakov Maxim A. ¹ , Starosotnikov Alexey M. ¹

Affiliations

1	N.D. Zelinsky Institute of Organic Chemistry RAS, Leninsky Prosp. 47, 119991 Moscow, Russia

An efficient method for the synthesis of pyrazolo [4,3-b]pyridines has been developed on the basis of readily available 2-chloro-3-nitropyridines via a sequence of SNAr and modified Japp–Klingemann reactions. The method offers a number of advantages including utilization of stable arenediazonium tosylates, operational simplicity as well as combining the azo-coupling, deacylation and pyrazole ring annulation steps in a one-pot manner. An unusual rearrangement (C-N-migration of the acetyl group) was observed and a plausible mechanism was proposed based on the isolated intermediates and NMR experiments. In addition, the developed protocol was successfully applied to the synthesis of 1-arylindazoles combining the Japp–Klingemann reaction and cyclization of the resulting hydrazone as a one-pot procedure.

Nikol’skiy V.V. , Minyaev M.E. , Bastrakov M.A. , Starosotnikov A.M.
Straightforward and Efficient Protocol for the Synthesis of Pyrazolo [4,3-b]pyridines and Indazoles
International Journal of Molecular Sciences. 2023. V.24. N2. 1758 . DOI: 10.3390/ijms24021758 WOS Scopus OpenAlex

Web of science:	WOS:000915416900001
Scopus:	2-s2.0-85146579529
OpenAlex:	W4316466286

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OpenAlex	4
Scopus	4
Web of science	4