Polyfunctional pyridines from nitroacetamidine and β‐diketones. A useful synthesis of substituted imidazo [4,5‐ b ] pyridines and related compounds

Nitroacetamidine undergoes a useful cyclocondensation with β‐diketones to produce substituted 2‐amino‐3‐nitropyridines. Use of an acylpyruvate generates hitherto unreported 2‐amino‐3‐nitropyridine‐4‐carboxylates. These may be converted easily to functionalized imidazo[4,5‐ b ]pyridines and oxazolo‐[5,4‐ b ]pyridines.