Tandem palladium-catalyzed borylation and Suzuki coupling (BSC) to thienocarbazole precursors

Substituted 2-methyl-2′-nitro diaryl compounds in the benzo[b]thiophene series were prepared by palladium-catalyzed, two-step, one-pot borylation/Suzuki coupling (BSC) reaction in good to high yields. The borylation reaction was performed on methylated 6-bromobenzo[b]thiophenes using pinacolborane and was followed by in situ Suzuki coupling with substituted (CF3, OMe) 2-bromonitrobenzenes. The compounds obtained were cyclized to the corresponding ring A substituted thienocarbazoles which can have biological activity or/and be used as biomarkers due to their fluorescence properties and possible DNA intercalation.