Some reactions of 2,3,4,5,6,7-hexachlorobenzo [b]thiophen

Article abstract of DOI:10.1016/S0040-4020(01)97147-9

2,3,4,5,6,7-Hexachlorobenzo[b]thiophen (1) reacts with n-butyl-lithium to give either the 2-lithio derivative or the 2,6-dilithio derivative depending on the reaction conditions; a mixture of mono (2-) and di (2,6-) Grignard reagents is formed from 1 and magnesium. Nucleophilic replacement of the 2-chlorine atom in 1 has been established for reaction with LAH; sodium benzenethiolate replaces a chlorine in the 5-membered ring, while a monosubstitution product is formed with sodium isopropoxide. 4,5,6,7-Tetrachlorobenzo[b]thiopen (5) was synthesised unambiguously and served as a model for ¹H NMR spectroscopy experiments. Catalytic hydrogenation of 1 [Pd-C] gives 5, (99% yield). Compound 1 forms the 1,1-dioxide (12) with peroxytrifluoroacetic acid, the vacuum pyrolysis of which gives hexachlorophenyl-acetylene.