Semicarbazon des 2-Hydroxy-4-methyl-acetophenons;1-(2-hydroxy-4-methyl-phenyl)-ethanone semicarbazone;1-(2-Hydroxy-4-methyl-phenyl)-aethanon-semicarbazon;[1-(2-hydroxy-4-methylphenyl)ethylideneamino]urea
The reaction of selenium dioxide with o-hydroxyacetophenone semicarbazones gives 4-(2-hydroxyaryl)-1,2,3-selenadiazoles which undergo ready decomposition by the action of potassium carbonate to form benzofuran-2-selenolates. The latter can be alkylated with methyl iodide and benzyl chloride and arylated with 2,4-dinitrochlorobenzene. Intermediate formation of 2-(o-hydroxyphenyl)ethyneselenolate during decomposition of 1,2,3-selenadiazoles was proved by the isolation of methyl o-methoxyphenylethynyl selenide when the substrate was treated with potassium carbonate in the presence of methyl iodide.