The chlorinalion of 3,5-dimethyl-1,2,4-oxadiazole

The clilorination of 3,5-dimethyl-1,2,4-oxadiazole has been studied using both photo and thermal initiation. It has been found that photoinitiation allows reaction at both the 3- and 5-methyl group, the former being preferred by a factor of 3-4 at moderate (up to 75° ) temperature. The difference in reactivity is related to a difference in electron availability at the two reaction sites. The thermally initiated chlorination occurs almost exclusively at the 5-methyl group. Overall, 3,5-dimethyl oxadiazole is much less active than toluene or cyclo-liexane toward chlorination.