Applications of Nitropyridine Isocyanates : Nitropyridine carbamates, amides and carboxylates in heterocyclic chemistry

Based on new methodology for nitration of pyridine developed by Professor Jan Bakke and coworkers at NTNU, a whole range of substituted nitropyridines are now readily available. Novel reactions with nitropyridine carbamates, amides and carboxylates are described in this work. Isocyanates constitute an important class of compounds in organic chemistry and undergo a series of reactions. Heterocyclic isocyanates, however, haven't received the same attention due to their instability and high reactivity. The study of nitropyridine isocyanates in cycloaddition reactions with azides, pyridine N-oxides and ketenes demonstrate their potential. Aromatic nucleophilic substitution of the nitro group and acid-catalyzed cyclization reactions of nitropyridine carbamates leading to the biologically active imidazopyridinone is also presented. The facile preparation of triazolopyridine and its application in the acylation of amines was also investigated. It proved to be more effective than the commercially available benzotriazole. This work is aimed at those interested in the applications of novel nitropyridine derivatives in organic chemistry.