organic compounds
The structural features of some 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles active against human immunodefiency virus (HIV) are reported. The diffractometric analysis reveals that the title compounds, 1-(2,4-difluorophenyl)-1H,3H-thiazolo[3,4-a]benzimidazole, C15H10F2N2S, 1-(2,6-dichlorophenyl)-1H,3H-thiazolo[3,4-a]benzimidazole, C15H10Cl2N2S, and 1-(2-chloro-4-fluorophenyl)-1H,3H-thiazolo[3,4-a]benzimidazole, C15H10ClFN2S, all adopt a butterfly like conformation which appears to be particularly important for the inhibition of HIV-1 reverse transcriptase (RT), an enzyme which plays a key role in the viral life cycle.