Communications

Sulfonyl derivatives of 1,4-dihydropyrazolo[5,1-c][1,2,4]triazines in reactions with acyl/alkyl halides

I. V. Ledenyova^a, P. A. Kartavtsev^a, D. Yu. Vandyshev^a, G. L. Denisov^b, Kh. S. Shikhaliev<sup>a

a</sup> Organic Chemistry Department, Voronezh State University, 394018 Voronezh, Russian Federation
^b A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119334 Moscow, Russian Federation

Abstract: The acylation reaction of 3-sulfonyl-1,4-dihydropyrazolo[5,1-c][1,2,4]triazines with acid chlorides on heating in the corresponding carboxylic acids gives the acylated derivatives at the N¹ atom of the as-dihydrotriazine ring. The analogous reactions with various alkyl halides in the K₂CO₃–MeCN system proceed similarly. When the alkylation with chloroacetanilides is performed on heating in K₂CO₃–DMF, a cascade rearrangement is initiated with the loss of the sulfonyl group and recyclization into 6-aminopyrazolo[1,5-a]pyrimidine-5-carboxamides.

Keywords: pyrazolo[5,1-c][1,2,4]triazines, pyrazolo[1,5-a]pyrimidines, sulfones, substitution, rearrangement, cascade reactions, acylation, alkylation, carboxamides, X-ray diffraction analysis.

Received: 10.06.2025
Accepted: 31.07.2025

Language: English

DOI: 10.71267/mencom.7846

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