Nitrogen heterocycles compounds

Hantzsch 2 gave the name pseudo bases to those carbinols that gave salts with acids by the elimination of water and a simultaneous change of constitution. Such carbinols are common among the nitrogen heterocyclic compounds and the naturally occurring alkaloids e.g., berberine, sanguinarine, chelerythrine. 

The third chapter Recent Developments in the Chemistry of N-Heterocyclic Phosphines presents a survey on five- and six-membered phosphorus-nitrogen heterocyclic compounds whose rings combine a phosphazene or phosphazane unit... 

Various schemes have been proposed to explain the production of nitrogen-containing heterocyclic compounds, such as pyrrolidines and piperidines, from proline. Nitrogen heterocyclic compounds are often potent flavouring chemicals. 

Use of chiral semicorrins and related nitrogen heterocyclic compounds as chiral ligands in asymmetric catalysis has been reviewed periodically. Interested readers are referred to the review by Pfaltz.102... 

Generalized valence bond interaction energies were computed for mono/poly-nitrogenous five- and six-membered heterocycles.203 Results that diverged from those obtained by other methods were obtained only for poly-nitrogenous systems such as pyridazine, benzotriazole, and tetrazole, which may confirm Bird s earlier finding123 204 that electron delocalization is not a stand-alone and direct measure of aromaticity for nitrogenous heterocyclic compounds. 

At that time, as now, the enantiomers of many chiral amines were obtained as natural products or by synthesis from naturally occurring amines, a-amino acids and alkaloids, while others were only prepared by introduction of an amino group by appropriate reactions into substances from the chiral pool carbohydrates, hydroxy acids, terpenes and alkaloids. In this connection, a recent review10 outlines the preparation of chiral aziridines from enantiomerically pure starting materials from natural or synthetic sources and the use of these aziridines in stereoselective transformations. Another report11 gives the use of the enantiomers of the a-amino acid esters for the asymmetric synthesis of nitrogen heterocyclic compounds. 

Stocks, P. G. and Schwarz, A. W. (1982). Basic nitrogen-heterocyclic compounds in the Murchison meteorite. Geochim. Cosmochim. Acta, 46, 309-15. 

More than 50% of all known organic compounds are heterocyclic compounds. They play important roles in medicine and biological systems. A great majority of important drugs and natural products, e.g. caffeine, nicotine, morphine, penicillins and cephalosporins, are heterocyclic compounds. The purine and pyrimidine bases, two nitrogenous heterocyclic compounds, are structural units of RNA and DNA. Serotonin, a neurotransmitter found in our body, is responsible for various bodily functions. 

POLYCYCLIC AROMATIC HYDROCARBONS NITROGEN HETEROCYCLIC COMPOUNDS LOW LEVEL CARCINOGENS FLYASH... 

Electro-oxidations of Nitrogen Heterocyclic Compounds , J. M. Bobbitt, in Proceedings of a Symposium on Heterocycles , ed. T. Kametani, Institute of Heterocyclic Chemistry, Sendai, 1977, pp. 50-51. 

Dumont, J. P., Roger, S. and Adda, J. 1975. Identification of a nitrogenous heterocyclic compound responsible for a potato-like off-flavor in Gruyere de Comte. Lait 55, 479-487. 

Zachara, J. M., et al., Sorption of Binary Mixtures of Aromatic Nitrogen Heterocyclic Compounds on Subsurface Materials. Environ. Sci. Technol., 1987 21, 397-402. 

The generation and reactivity of conjugated azomethine ylides has been reviewed.148 1,3-Dipolar cycloaddition and 1,5- and 1,7-electrocyclizations have been described as powerful strategies for the synthesis of monocyclic and annulated five- and seven-membered nitrogen heterocyclic compounds. 

The Chemistry of Unsaturated Nitrogen-Heterocyclic Compounds Containing Carbonyl Groups... 

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