2-Chloro-5-nitronicotinic acid

2-Hydroxy-5-nitro-nicotinic acid (2.7 mmol) in a mixture of NJV- dimethylformamide (2.7 mmol) and thionyl chloride (5 ml) was heated at 80 0C for 1 h. The mixture was allowed to cool and concentrated in a vacuum. To the resulting residue, ice water (20 ml) was added, and with vigorous stirring, a precipitate formed. The precipitate was filtered off and dried in a vacuum oven to give a white solid 2-Chloro-5-nitronicotinic acid (68 percent).