SYNTHESIS AND DECOMPOSITION OF 1-METHYL, 1-HYDROXY AND 1-METHOXYCYCLOHEXYL HYDROTHEROXIDES
During the past 4 decades, studies on polyoxides did not stopped. Nowadays, hydrogen trioxide and organic derivatives (i.e. alkyl hydrotrioxides) are at the focus of the studies. As it was shown by NMR, these substances can be involved in the low-temperature ozonation of C-H bound as unstable intermediates. According to recent studies, it is most likely that hydrogen trioxide is produced in biological systems of antibodies, as well as in peroxide reactions with ozone (peroxone chemistry). The authors of the present work studied synthesis of 1-methyl, 1-hydroxy and 1-methoxycyclohexyl hydrotheroxides and their decomposition. The preparation was carried out by low-temperature ozonation of methylcyclohexane, cyclohexanol and methoxycyclohexane in tert-butyl methyl ether at -78 °С. The hydrotrioxides were characterized by a typical OOOH 1H NMR absorptions at 13.60, 14.2 and 13.03 ppm respectively downfield from TMS (-50 °С, CF3Cl/toluene-d6). The decomposition product of 1-methylcyclohexyl hydrotheroxide was corresponding to alcohol. In the cases of 1-hydroxy and 1-methoxycyclohexyl hydrotheroxides, the product was cyclohexanone. And in all three cases, the product was also singlet oxygen. The yield of singlet oxygen during thermolysis of hydrotrioxides was determined by the method based on chemiluminescence in the IR region of the spectrum. As a standard in quantifying the yield of singlet oxygen, triphenyl phosphite ozonide was used, which quantum yield is known. The highest yield of singlet oxygen is observed in the process of decomposition of the 1-hydroxy derivative. Apparently, the hydroxyl group stabilizes the transition state for the molecular transformation or promotes the conservation of the singlet state during disproportionation of the radical pair [RO• •OOH] in the solvent cell.