The addition of simple aromatic hydrocarbons to condensed aromatic thiophenes promoted by aluminum chloride. Part I. Naphtho[2,1-b]thiophene

Naphtho[2,1-b]thiophene undergoes addition of aromatic hydrocarbons across the 1,2-bond in the presence of aluminum chloride. At 20 °C 1-aryl-1,2-dihydronaphtho[2,1-b]thiophenes are the major products and at higher temperatures 2-arylnaphtho[2,1-b]thiophenes result. 1-Arylnaphtho[2,1-b]thiophenes may be prepared by treatment of the dihydro-addition products with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone thus giving a new synthesis of 1- and 2-arylnaphtho[2,1-b]thiophenes from the parent heterocycle.