Phosphorus oxychloride → 3-Formyl-2-methyl-8-nitro-imidazo[1,2-a]pyridine

Participants

Reaction Conditions

Reaction Steps

20 ml phosphoroxychloride is added dropwise within 5 minutes to a solution of 7.6 g 2-methyl-8-nitro-imidazo[1,2-a]pyridine in 100 ml dimethylformamide at 0° C. After stirring for 1 hour at 0° C. and for 2 hours at 70° C. the mixture is cooled again to 0° C. 10 ml phosphoroxychloride is added dropwise and the same procedure is carried out as before. When the reaction is finished the mixture is poured over 200 ml icewater, neutralized with saturated sodium hydrogen carbonate solution and extracted 3×with 50 ml ethyl acetate each time. The solvent is stripped off in vacuo and the residue is washed with ether and recrystallized from acetronitrile, giving the title compound of m.p. 188°-189° C.

Provenance & Evidence