Synthesis and identification of new thieno[3,2-b] benzothiophenes

The reaction of 2-lithiobenzob]thiophenes with ketones produced 2-hydroxyalkylbenzob]thiophenes which were cyclized in thionyl chloride to give novel thieno3,2-b]1]benzothiophenes. Oxidation with peroxyacetic acid gave the S,S-dioxides whose regiochemistry was identified from ¹H nmr model studies using substituted benzob]thiophenes and their corresponding-1,1-dioxides 1].