Kinetics and mechanism of pyrolysis of sulphonyl hydrazones and oximes. Part 1. Contribution to reactivity from hydrazone HN-N and oxime O-N bond polarity

Article abstract of DOI:10.1016/S0040-4020(98)00179-3

Rates were obtained for the pyrolysis of tosyl arenecarboxaldehyde hydrazones (1-5), and mesyl benzaldoxime (6). The substituted tosyl sulphonamides (TsHNN-CHAr: 1-5) and the mesylate (6) gave in a novel pyrolytic reaction the following Arrhenius log A/s^-1 and E(a)kJ mol^-1 values, respectively: 12.70 and 157.7 (1, Ar- C₆₅), 12.29 and 152.6 (2, p- NO₂C₆H₄), 11.85 and 148.2 (3, m-NO₂C₆H₄), 12.17 and 152.0 (4, p- ClC₆H₄), 11.01 and 140.8 (5, p-CH₃OC₆H₄), and 12.96 and 109.9 for (6). Tosyl benzaldoxime (7) was also studied. The reactions yielded cyanoarenes together with sulphonic acids from 6 and 7, and pmethylbenzenesulphonamide from compounds 1-5.