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Reactions of 1,2‐Dimethyl‐5‐nitroimidazole, novel methods of conversion of the 2‐Methyl group to a nitrile
Author(s) -
Albright J. Donald,
Shepherd Robert G.
Publication year - 1973
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.5570100603
Subject(s) - chemistry , triethylamine , thionyl chloride , enol , nitrile , pyridinium , medicinal chemistry , nitroimidazole , pyridinium chlorochromate , chloride , organic chemistry , oxalyl chloride , methyl group , pyridine , catalysis , group (periodic table)
1, 2‐Dimethyl‐5‐nitroimidazole( 1 )and N,N ‐dimethylformamide dicyclohexylacetal gave the 2‐(β‐dimethylaminovinyl) analog 2 and with iodine and pyridine gave the 2‐(1‐pyridinium)methyl compound 3 . Benzoyl chloride‐triethylamine and 1 led to benzoylation of the 2‐methyl group to give ketone 9 as the enol benzoate. Nitrous acid or nitrosylsulfuric acid with 9 or its enol ester afforded the oximinoketone 10 which was cleaved with thionyl chloride to give 2‐cyano‐1‐methyl‐5‐nitroimidazole ( 11 ) in high overall yield. 1‐Ethyl‐2‐methylbenzimidazole ( 22 ) was converted to 2‐cyano‐1‐ethylbenzimidazole ( 25 ) similarly. Reaction of 1 with ethyl oxalyl chloride and triethylamine afforded ethyl 1‐methyl‐5‐nitro‐2‐imidazolepyruvate ( 19 ) as the enol oxalate. Nitrous acid and 19 gave the oximino pyruvate 20 which effervesced on mild heating to give 2‐cyano‐1‐methyl‐5‐nitroimidazole ( 11 ). The preparation of 1‐methyl‐5‐nitro‐2‐imidazoleacetonitrile ( 39 ) is reported.