5,5 -Disubstituted 2,2 -bithienyls

A mixture of S-trans and S-cis forms in 5,5 disubstituted 2,2 -bithienyls accounted for the experimental liquid crystal NMR data (73JCS(P2)751, 74JA1305, 74MP(28)441). 

The acetylation and formylation of 2,2 -bithienyl give monosubstitution in the 5-position, - Disubstitution is easily achieved and, in some cases, difficult to avoid as the deactivating effect of a substituent is not very strongly transmitted to the other ring. The nitration of 2,2 -bithienyl has recently been studied. ... 

It seems quite obvious that the thiophenes are related to the polyacetylenes which they accompany. This viewpoint has recently been illustrated by the formation of thiophenes from polyacetylenes and hydrogen sulfide under almost biological conditions. In a recent lecture summary, the preparation of terthienyl, junipal, and (241) from 1,4-disubstituted butadiynes and hydrogen sulfide is claimed. A large number of bithienyls have been prepared and their nemato-dicidal activity investigated. All the compounds with strong activity were found to be derivatives of 2,2 -bithienyl. ... 

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