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Keywords: 1-arylsulfonyl-1,1-dihydropolyfluoro-2-alkanone, enaminone, pyrazole, pyrimidine, Vilsmeier-Haack-Arnold reaction, X-ray diffraction structural analysis.Fluoropyrazoles and fluoropyrimidines display a variety of strong biological activities [1][2][3][4][5], which has led to work to develop new methods for the synthesis of such heterocyclic compounds.The synthetic approaches for the heterocyclic pyrazole system have been studied extensively. The most common approach involves a reaction, in which the three-carbon fragment of a β-dicarbonyl compound or its synthetic equivalent is condensed with the diatomic N-N fragment of hydrazine or its derivative. A problem with this approach is the regioselectivity of the reaction using asymmetric starting compounds since a mixture of N-substituted pyrazoles is formed in most cases [6]. The similar reaction of β-dicarbonyl compounds with a binucleophile possessing an N-C-N fragment leads to the formation of pyrimidines and is also frequently used for the design of these heterocycles [7].In the present work, we studied the feasibility of using 1-dimethylamino-2-(p-tolylsulfonyl)-polyfluoro-1-alken-3-ones 2a,b, which are the synthetic equivalents of a new type of β-dicarbonyl compounds, namely, 1-arylsulfonyl-2-oxopolyfluoroalkanals 1a,b for the regioselective synthesis of fluoropyrazoles and fluoropyrimidines. Monoenamines of various 1,3-dicarbonyl compounds (amide vinylogs) have found common use in the synthesis of many heterocyclic systems [8].

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