Ethyl Oxalyl Research Articles

Reactions of 1,2‐Dimethyl‐5‐nitroimidazole, novel methods of conversion of the 2‐Methyl group to a nitrile

Abstract1, 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.