Convenient Synthesis 5H-[1,2,4]Triazine[5,6-b]indole-3-thiol Derivatives
2-Methyl(ethyl)aniline 1a, 1b were first underwent the Sandmeyer reaction to give 7-methyl (ethyl) isatins 2a, 2b. The resulting 2a, 2b were then subjected to the bromination reaction with N-bromosuccinimide (NBS) using eco-friendly PEG-400 as solvent at room temperature to afford 5-bromo-7-methyl (ethyl) isatins 3a, 3b. Compounds 2a, 2b, 3a, 3b were further alkylated at the nitrogen atom to give the corresponding 1-alkylation-7-methyl. (ethyl) isatins 4a similar to 4j, and 1-alkylation-5-bromo-7-methyl(ethyl)isatins 5a similar to 5j. Finally, 2a, 2b, 3a, 3b, 4a similar to 4j, 5a similar to 5j were subjected to the condensation reaction with thiosemicarbazide using dioxane as solvent and potassium carbonate as alkali to successfully synthesize 24 kinds of 5H-[1,2,4]triazine[5,6-b]indole-3-thiol derivatives 6a similar to 6x. Most of compounds were new and their structures were confirmed by IR, MS, H-1 NMR and C-13 NMR spectra and elemental analyses.
7-methyl(ethyl)isatin; 5-bromo-7-methyl(ethyl)isatin; bromination; alkylation; 5H-[1,2,4]triazino-[5,6-b]-indole-3-thiol
