Kinetics and mechanism of pyrolysis of sulphonyl hydrazones and oximes. Part 1. Contribution to reactivity from hydrazone HNî—¸N and oxime Oî—¸N bond polarity
By Al-Awadi, Nouria A; Elnagdi, Mohamed H; Kaul, Kamini; Ilingovan, Swaminathan & El-Dusouqui, Osman M.E
Published in Tetrahedron
1998
Abstract
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 Ea/kJ mol-1 values, respectively: 12.70 and 157.7 (1, Arî—»C6H5), 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 p-methylbenzenesulphonamide from compounds 1–5.