Chapter 1 - Raney nickel-assisted nitro group reduction for the synthesis of five-membered N-heterocycles

Abstract

The N-containing heterocyclic compounds have attracted attention in the past few decades due to their high therapeutic values. Whether they are synthetic or natural one, they are elaborated as important constituents in biological procedures due to their remarkable biological features. Various N-containing heterocyclic compounds particularly, in plant kingdom have made indelible mark as phytochemical medicines like theophylline, quinine, emetine, procaine, ellipticine, codeine, morphine, and papaverine. Besides, the massive distribution of N-containing heterocyclic compounds in natural products, they also play a key role in the biochemical procedures in living cells. Most of the enzymes have aromatic heterocyclic compounds as main elements while most of the coenzymes having nonamino acids functionalities are aromatic N-containing heterocyclic compounds and some important vitamins are formed on aromatic heterocyclic framework. Additionally, N-containing heterocyclic compounds have been often found as an important structural unit in synthetic medicines like antipyrine, chlorpromazine, metronidazole, captopril, chloroquinine, barbituric acid, isoniazid, azidothymidine, and diazepam. Significant focus has been paid to novel approaches for the formation of N-containing heterocyclic compounds, which are natural biologically active organic compounds or pharmacophoric fragments.