Oligomeriazation of the thiophene-based p-quinodimethanes 2,5-dimethylene-2,5-dihydrothiophene and 2-ethylidene-5-methylene-2,5-dihydrothiophene

摘要

Flash vacuum pyrolysis (FVP) of (5-methyl-2-thiophene-yl)methyl benzoate (8) produces in ca. 75/100 yield 2,5-dimethylene-2,3-dihydrothiophene, S-monomer (3). S-Monomer 3 is relatively stable dissolved in carbon disulide-chloroform at-78/100. The structure of 3 is confirmed by its spectral properties. When a 0.17 M solution of S-monmer 3 was allowed to warm to room temperature, SS-dimer 5([2,2](2,5)thiophenophane, 14.7/100), SSS-trimer 7 ([2,2,2](2,5)thiophenophane, 44.3/100), And polymer were producd.