Synthesis of New tert-Butyl- and Bromo-functionalized [1,2,4]Triazino [5,6-b]indole-3-thiols and Indolo[2,3-b]quinoxalines

In the present investigation, the synthesis of a series of structurally new and interesting tert-butyl- and bromo-functionalized [1,2,4]triazino[5,6-b]indoles (6a-f) and indolo[2,3-b]quinoxalines (8a-f) has been achieved, involving the condensation reaction of 7-bromo-5-tert-butylisatins (4a-f) with thiosemicarbazide (5) and benzene-1,2-diamine (7). The substrates 4a-f were prepared through bromination reaction of 5-tert-butylisatin (3) with NBS in PEG-400 followed by alkylation reaction. The molecular structures of these newly synthesized compounds were elucidated on the basis of their elemental analyses and spectral data.