First N ‐Functionalization of 4‐Nitroso‐1 H ‐Pyrazoles Using Monofunctional and Bifunctional Alkylating Agents

• Published in: ChemistrySelect (Weinheim) Vol. 8; no. 28
• Main Authors: Bobrova, Anastasiia V., Krasnov, Pavel O., Radzhabov, Amirbek D., Kondrasenko, Alexander A., Root, Evgeniy V., Suboch, Georgii A.
• Format: Journal Article
• Language: English
• Published: 26-07-2023
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202302031

The direct
N
‐alkylation reactions of ambident 3,5‐substituted 4‐nitroso‐1
H
‐pyrazoles are described for the first time. An efficient method of the 4‐nitroso‐1
H
‐pyrazoles and their sodium alkyl‐, allyl‐ salts regioselective
N
‐alkylation by benzyl halides, halocarboxylic acids esters, and related bifunctional alkylating agents is established with the use of superbasic conditions or reflux in acetone. A series of new
N
‐functionalized nitrosopyrazoles and bis(4‐nitrosopyrazole) compounds is successfully obtained with a yield of up to 85 %. Using quantum‐chemical calculations, it is shown that in terms of kinetics and thermodynamics, the
N
‐alkylation of the considered pyrazoles is a more advantageous process than
O
‐alkylation.