Synthesis of 4H-Benzopyranothiadiazol-4-one and Its Reactions with Some Nucleophilic and Electrophilic Agents

Article abstract of DOI:10.1007/BF00633181

The reaction of 3,4-diaminocoumarin with thionyl chloride gave 4H-<1>benzopyrano<3,4-c><1,2,5>thiodiazol-4-one (II), which was cleaved by the action of nucleophilic agents to the corresponding 4-(2-hydroxyphenyl)-1,2,5-thiadiazole-3-carboxylic acid derivatives.The nitration of II leads to the 8-nitro or 6,8-dinitro derivative; the latter was isolated in the form of 4-(2-hydroxy-3,5-dinitrophenyl)-1,2,5-thiadiazole-3-carboxylic acid.