S. Gronowitz, R. Kada
Jul 1, 1984
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0
Influential Citations
8
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
Metalation of 1-methylpyrrole using n-butyllithium and tetramethylethylenediamine (TMEDA) in ether furnished 1-methyl-2-pyrrolyllithium, which in turn was converted to 1-methyl-2-methylthiopyrrole upon treatment with dimethyldisulfide. Further formylation with dimethylformamide, phosphorus oxychloride in dichloroethane led to the corresponding pyrrole-2-carboxaldehyde, which was then condensed with malononitrile and methylcyanoacetate under Knoevenagel reaction conditions to give 2-cyano-3-(1-methyl-5-methylthio-2-pyrrolyl)acrylonitrile and 2-cyano-3-(1-methyl-5-methylthio-2-pyrrolyl)acrylic acid methyl ester, respectively. Their oxidation by hydrogen peroxide furnished the corresponding sulfones. Analogously, 5-phenylthio derivatives were prepared.