Synthesis and Characterization of Some 5-Substituted 2-Thiol/Thione-1,3,4-Oxadiazoles

摘要

5-(4-Aminophenyi)-2-thiol-1,3,4-oxadiazole (1) was synthesized via the reaction of carbon disulfide with 4-aminobenzoyi hydrazide. Compound 1 was converted to the corresponding diazonium salt which was introduced in coupling reaction with sodium phenoxide as coupling reagent to give azo-oxadiazole derivative containing aldehyde group 2. The resulting aldehyde 2 was men introduced in acid-catalyzed condensation reactions with both 2-aminobenzothiazole and 2-amino-5-mercapto-l,3,4-thiadiazole to obtain the oxadiazolic-imines 3a and 3b, respectively. Treatment of the resulting imines 3a and 3b with each succinic acid, maleic acid, phthalic acid and 3-nitrophthalic anhydrides, respectively, under (2+5) cycloaddition conditions afforded eight new oxadiazoles substituted with 1,3-oxazepane and 1,3-oxazepine moieties 4a-d and 5a-d, respectively. The resulting imines 3a and 3b were also treated with sodium azide under (2+3) cycloaddition conditions to obtain two new oxadiazoles containing tetrazole moiety 4e and 5e, respectively. The newly synthesized oxadiazoles might have some biological, pharmaceutical and medicinal applications.