| Abstract
| - The effectiveness of the 2,4-dinitrobenzenesulfenyl and4-nitrobenzenesulfenyl groups as masking and directinggroups at the 2-position of pyrrole has been investigated andcompared to that of 2-phenylthiopyrrole. The presence ofthe nitro group(s) enhances stability of the correspondingpyrrole toward acid and does not significantly decrease theability of the pyrrolic unit to undergo electrophilic aromaticsubstitution reactions in the form of formylation, nitration,and condensation with aldehydes. The synthetic utility of2-(2,4-dinitrobenzenesulfenyl)pyrrole was demonstratedthrough the synthesis of meso-substituted dipyrromethanes.The sulfoxides 2-(2,4-dinitrobenzenesulfinyl)pyrrole and2-(4-nitrobenzenesulfinyl)pyrrole underwent neither formylation nor nitration, and the increasing presence of nitrogroups within the moiety at the 2-position resulted indecreased stability under acidic conditions.
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