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Sulfur derivatives of 1‐methylpyrrole
Author(s) -
Gronowitz Salo,
Kada Rudolf
Publication year - 1984
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570210423
Subject(s) - chemistry , malononitrile , acrylonitrile , butyllithium , formylation , metalation , organic chemistry , medicinal chemistry , dimethylformamide , catalysis , polymer , solvent , copolymer
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.