Synthesis and reactivity of 7-r-3-r’-4-oxo-8-(2<i>H</i>-tetrazole-5-yl)- 6<i>h</i>-pyrazolo[5,1-<i>с</i>][1,2,4]triazine
Purpose of research - to study the reactivity of a nitrogen-containing heterocyclic compound containing a 1,2,4-triazine ring. Methods. A thermal synthesis method was used. Infrared spectra in a thin layer of samples were recorded using an IR spectrometer. The electronic spectrum was recorded in water on a spectrophotometer. A spectrometer (300 MHz - operating frequency) was used to record the proton magnetic resonance spectrum. The mass spectrum was recorded on a MS-1302 mass spectrometer. The Sorbfil plates were chromatographed and processed in a computer program using a video densitometer. The purity of the products was monitored using thin-layer chromatography (Silufol UV - 254 plates). Results. The preparation of 7-R-3-R'-4-oxo-8-(2H-tetrazol-5-yl)-6H-pyrazolo[5,1-c][1,2,4 triazine was carried out under the action of NaN3 and NH4Cl the derivative of pyrazolo[5,1-c [1,2,4]triazine-8-carbonitrile in a polar solvent. The reaction mechanism is considered, which includes 1,3-dipolar cycloaddition. In this case, the H-linked complex of ammonia with hydrazoic acid acts as a 1,3-dipole, which attacks the carbon atom of the cyano group to form ammonium tetrazolide. Ammonium tetrazolide was stabilized by adding dilute hydrochloric acid. Carrying out the reaction under microwave heating conditions is not feasible, due to the use of sodium azide, which can explode when exposed to radiation. The structure is confirmed by a set of elemental analysis and spectral data. The kinetics of the reaction was studied and it was found that the reaction has the second order, which was determined by the graphical method (the value of the reliable approximation in the 1/C-T coordinate system was 0.9901). Determined k = 3.23∙10-3 l/mol∙min. Conclusion. Thermally synthesized 7-R-3-R'-4-oxo-8-(2H-tetrazol-5-yl)-6H-pyrazolo[5,1-c][1,2,4]triazine. The mechanism of the reaction of the cyclization of the tetrazole ring is proposed and the reaction order (second) and the reaction rate constant (3.23∙10-3 l/mol∙min) have been determined.