1,2,3-Triketone 2-(antipyrin-4-yl)hydrazones were synthesized via the azo-coupling reactions of 1,3-diketones with 2-(antipyrin-4-yl)diazonium chloride. The fluoroalkyl-containing hetarylhydrazone enters into cyclocondensation with hydrazines at the 1,3-dicarbonyl fragment to yield 3-tetrafluoroethyl derivatives of pyrazole. It was found that 1,2,3-triketone 2-(antipyrin-4-yl)hydrazones and N-(2-hydroxyethyl)-substituted pyrazole exhibit analgesic activity comparable with that of their structural analog analgin (metamizole sodium), but do not possess antipyretic properties. In contrast, N-phenyl-substituted pyrazole did not exhibit analgesic properties but produced a certain antipyretic effect four hours after pyrogenic administration. Fluoroalkyl-containing compounds are less toxic substances than nonfluorinated 2-(antipyrin-4-yl)hydrazone and analgin.As is known, the widely used analgesic and antipyretic drugs are rather toxic substances [1]. We attempted to modify the antipyrine structure so as to obtain new low-toxicity compounds possessing analgesic and antipyretic properties.Using the azo-coupling reactions of 1,3-diketones (Ia and Ib) with 2-(antipyrin-4-yl)diazonium chloride (II) in the presence of sodium acetate, we obtained the corresponding 1,2,3-triketone 2-(antipyrin-4-yl)hydrazones (IIIa and IIIb). The proposed structures of these products were confirmed by the data of elemental analyses and the results of IR and 1 H NMR spectroscopic measurements. Indeed, the presence of characteristic absorption bands due to carbonyl groups (at 1660 -1680 cm -1 ) and a weak band due to the stretching vibrations of amino groups of the hydrazone fragment (at 3300 -3470 cm -1 ) in the IR spectra, as well as the absence of signals from methane protons in the 1 H NMR spectra, showed evidence for a hydrazone-diketone tautomer structure of the synthesized compounds.

No abstract

No abstract

No abstract