Thiophene synthesis from oximes

For the first time, the reaction of ketoximes with acetylene has been applied for the preparation of pyrroles bonded with the thiophene ring in the work [244], which describes synthesis of 2-(2-thienyl)pyirole (in 60% yield) from 2-acetylthio-phene (via its oxime) in the system KOH/DMSO (100°C-140°C). In the presence of acetylene excess under the same conditions, 2-(2-thienyl)-N-vinylpyrroles (50% yield) is formed. 

SCHEME 1.61 Synthesis of 2-(benzo[f>]thiophen-3-yl)-N-vinylpyrrole from 3-acetylbenzo[h]thiophene oxime and acetylene. 

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