3,5-Dihydro-2H-thieno[2,3-c]pyrrole 1,1-dioxide - A new simple pyrrole unit. Preliminary communication

Article abstract of DOI:10.1002/hlca.200900362

2,3-Dihydrothiophene 1,1-dioxide ('2-sulfolene') reacted with tosylmethyl isocyanide (TsMIC) in the presence of a base to give the hitherto unknown 3,5-dihydro-2H-thieno[2,3-c]pyrrole 1,1-dioxide ('β′- sulfolenopyrrole') from the expected cyclocondensation. A serendipitous formation of this β′-sulfolenopyrrole was found earlier, when we investigated synthetic routes to a 3,5-dihydro-1H-thieno[ 3,4-c]pyrrole 2,2-dioxide (a 'β″-sulfolenopyrrole') from TsMIC and 2,5-dihydrothiophene 1,1-dioxide ('3-sulfolene'). Here, we present the synthesis and characterization of β′-sulfolenopyrrole. The X-ray crystal-structure analyses of β′-sulfolenopyrrole and the isomeric β″-sulfolenopyrrole are also reported here. This β′- sulfolenopyrrole is a new type of a functionalized pyrrole, which is likely to be of interest for pharmaceutical purposes.