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4,5‐Dimethylimidazole: A correction and alternative synthesis
Author(s) -
D'Sa Albinus,
Cohen Louis A.
Publication year - 1991
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.5570280730
Subject(s) - chemistry , thionyl chloride , hydrogenolysis , yield (engineering) , nitromethane , derivative (finance) , formic acid , adduct , organic chemistry , chloride , catalysis , materials science , economics , financial economics , metallurgy
Abstract Fractional vacuum distillation of the product obtained from thermal condensation of acetoin with formamide is a formic acid complex of 4,5‐dimethylimidazole, and not the expected free base. The 1 H and 13 C nmr spectra suggest that the product may be closer to a 1:1 hydrogen‐bonded adduct than to a true salt. Commercial 4‐hydroxymethyl‐5‐methylimidazole is converted quantitatively to the 4‐chloromethyl derivative with thionyl chloride; hydrogenolysis of the latter compound provides 4,5‐dimethylimidazole in an overall 80–90% yield, doubling the yield obtained by the classical method.