Studies on anticoccidial agents. 10. Synthesis and anticoccidial activity of 5-nitronicotinamide and its analogues

5-Nitronicotinamide (1) was prepared from 5-bromonicotinoyl chloride by treatment with ammonia and then oxidation with fuming H2SO4 and 30% H202. 2-Cholor-, 2-alkoxy-2-benzyloxy,2-phenoxy-,2-alkylamino-, and 2-benzylamino-5-nitronicatinamides were also prepared via 2-chloro-3-cyano-5-nitropyridine. 2-Methyl-5-nitronicotinamide (2) was obtained from ethyl 2-methyl-5-nitronicotinate by treatment with ammonia; the 4-methyl analogue 3 was from 3-cyano-2,6-dihydroxy-4 methylpyridine by nitration, chlorination, and dechlorination, and the 6-methyl analogue 4 was prepared by transforming 2-chloro-3-cyano-6-methyl-5-nitropyridine to the corresponding amide, followed by dechlorination. Of these compounds, the 5-nitronicotinamide, the 2-methyl and 4-methyl but not the 6-methyl, analogue showed significant anticoccidial activity against eimeria tenella. N-Substituted analogues of 5-nitronicotinamide and 2-methyl-5-nitronicotinamide were prepared in a conventional manner and optimal anticoccidial activity was attained with their lower N-alkyl analogues, N-alkanoyl and -alkenoyl analogues, and N-aromatic acyl analogues together with these parent compounds.