Amidines with a trichloromethyl group exhibit the properties of inotropic agents, which are used as scaffolds in synthesizing aza-heterocycles and ligands for complex formation. Functionalized amidines show anticancer, and antidiabetic activity, and are antihypertensive and antiparasitic agents. The synthesis of new functional derivatives of such amidines is definitely an urgent task. The introduction of an alkenyl substituent and several nucleophilic centers in the amidine creates prerequisites for electrophilic cyclization. This work aims to study the reactions of N-allyl-N-methyl-N'-(trimethylsilyl)-2,2,2-trichloroethanimidamide with tellurium halides.
The starting N-allyl-N-methyl-N'-(trimethylsilyl)-2,2,2-trichloroethanimidamide was synthesized from N-allyl-N-methyl-2,2,2-trichloroethanimidamide by the action of trimethylsilyl chloride in the presence of triethylamine base. The reaction of N-allyl-N-methyl-N'-(trimethylsilyl)-2,2,2-trichloroethanimidamide with tellurium dioxide in hydrohalic acid was carried out while cooling to 0°C. Elemental analysis confirms that the electrophilic reagent is in its acidic form in the complex. The 1H NMR spectra of the obtained complexes indicate the absence of EVC - the spin pattern of the proton signals of the allylic substituent, characteristic of the starting compounds, is preserved, but the signals are shifted by 0.3–0.6 ppm. The absence of proton signals of the trimethyl salt substituent indicates the removal of imide protection under these conditions. The presence of a broadened singlet in a weak field indicates the presence of acidic protons. Apparently, protonation does not take place on the alkenyl multiple bonds, but, presumably, on the imide nitrogen atom. Based on elemental analysis, the composition of the formed complex was determined: N-allyl-N-methyl-2,2,2-trichloroethanimidamidine: hexahalogenotelluric acid as 1:0.5, which contains 4 or 3 water molecules. So the interaction of N-allyl-N-methyl-N'-(trimethylsilyl)-2,2,2-trichloroethanimidamide with tellurium tetrahalides in a strongly acidic environment, tellurium- or proton-induced cyclization does not occur, but hexahalogenotellurate N-allyl-N-methyl-2,2,2-trichloroethaneimidamidinium regardless of the polarity of the solvent.
