General procedure for the synthesis of 5-nitro-2-pyridinecarboxylic acid from 2-bromo-5-nitropyridine: this method is based on the procedure reported by Oehlke, J.; Schroetter, E.; Dove, S.; Schick, H.; Niedrich, H. in Pharmazie 1983,38,591-596, with slight modifications. When N,N-dimethylformamide (DMF) was used instead of dimethylsulfoxide (DMSO) as solvent for the reaction with 2-bromo-5-nitropyridine and copper(I) cyanide, a subsequent hydrolysis step afforded the target product 5-nitro-2-pyridinecarboxylic acid in 70% yield. This product is usually used directly in subsequent reactions without further purification.
[1] Patent: WO2004/14904, 2004, A1. Location in patent: Page 53
[2] Pharmazie, 1983, vol. 38, # 9, p. 591 - 596
[3] Hoppe-Seyler's Zeitschrift fuer Physiologische Chemie, 1951, vol. 288, p. 237,241
[4] Patent: WO2009/141386, 2009, A1. Location in patent: Page/Page column 89
