摘要：

Kinetic H/D Isotope Effect of the Photooxidation of 3,5-Dimethyl-1,1-dioxo-2-(p-tolyl)-1,2-thiazine by Singlet Oxygen The hydrogen atoms of the thiazine ring and of the methyl groups of 3,5-dimethyl-1,1-dioxo-2-(p-tolyl)-1,2-thiazine 1a can be exchanged by deuterium in basic or acidic deutero methanol (CH 3 OD). In CD 3 OD/D 2 SO 4 the rate of the H/D-exchange of the different protons of 1a was determined by 1 H-n.m.r. spectroscopy. A kinetic isotope effect of 1.5–1.8 was determined from the rate of the oxygen consumption and also by using a competitive method. The results are in accordance with an "ene" reaction of 1a with singlet oxygen.

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