Researches on 2,1,3-thia-and selenadiazoles

Chloromethylation of 4- and 5-chlorobenzo-2,1,3-thiadiazoles with dichlorodimethyl ether in the presence of anhydrous aluminum chloride gives 4-chloro-7-chloromethyl- and 5-chloro-4-chloromethylbenzo-2, 1,3-thiadiazoles respectively. Reductive scission followed by treatment with thionyl chloride converts them to 4-chloro-7-methyl- and 5-chloro-4-methylbenzo-2,1,3-thiadiazoles; Chlorination of the latter gives 4-methyl-5,7-dichlorobenzo-2,1,3-thiadiazole. Replacement of the chlorine in the chloromethyl groups gives 4-chloro-7-hydrosymethyl-,5-chloro-4-hydroxymethyl-, 4-chloro-7-cyanomethyl-,4-chloro-7-carboxymethyl-,5-chloro-4-carboxymethylbenzo-2,1,3-thiadiazoles. Reductive scission of 4-chlorobenzo-2,1,3-thidiazole followed by treatment with sodium selenite gives 4-chlorobenzo-2,1,3-selenadiazole.Part XLIII see 1].