Polycyclic aromatic nitrogen-containing hydrocarbons

As early as 1964, polycyclic aromatic hydrocarbons (PAHs) known to be carcinogenic, such as benzo[a]pyrcne, were detected in broiled meat (164). A number of papers have been published about PAHs found in smoked and thermally treated foods as a result of pyrolysis or incomplete combustion of organic matter (165 -169). Less information is available on the nitrogen analogs, the basic azaarenes polycyclic aromatic nitrogen-containing hydrocarbons (PANHs), but they have been shown to be present in association with PAHs in various samples that contain nitrogen, such as processed food (170-172). 

Polycyclic aromatic compound Polycyclic aromatic hydrocarbon Polycyclic aromatic sulfur heterocycle Polycyclic aromatic oxygen heterocycle Nitrogen-containing polycyclic aromatic compound (both heterocyclic and nonheterocyclic compounds) Secondary-nitrogen polycyclic aromatic nitrogen heterocycles (nitrogen in a five-membered ring)... 

Cedric Brule is a postdoctoral fellow since 2006 in Professor J. Marchand-Brynaert s Organic and Medicinal Chemistry Laboratory at the Universite catholique de Louvain (UCL) at Louvain-la-Neuve, Belgium. He received his Ph.D. degree in Chemistry in 2004 for studies on trifluoro-methylated nitrogen-containing heterocycles in Professor Charles Portella s laboratory at the University of Reims, France. His Ph.D. studies were in collaboration with the Cerep Pharmaceutical Company in Paris, where he also worked for 6 months. Afterward, he spent 1 year of postdoctoral research in Professor Kenneth K. Laali s laboratory at Kent State University (Ohio, USA, 2005-06), supported by an NIH grant, to work on polycyclic aromatic hydrocarbons (PAHs) in the field of carbocations chemistry. 

Chemical Formula A distillate of coal that contains an estimated 162 different compounds. Estimated make-up is as follows aliphatic hydrocarbons (7%), polycyclic aromatic hydrocarbons (69%), and nitrogen containing polycyclic aromatic hydrocarbons (11%). Some of the polynuclear aromatic hydrocarbons identified in creosote are anthracene, benz(a)anthracene, benzo(d )pyre-ne, and pyrene... 

Polycyclic aromatic hydrocarbons Alkylated aromatic hydrocarbons Chlorinated aromatic compounds Chlorobenzenes Polychlorinated biphenyls Polychlorinated dibenzo[l,4]dioxins Chlorinated guaiacols and catechols Nitrogen-containing aromatic compounds Azaarenes and aromatic nitriles Oxygenated aromatic compounds 2,4-Dipentyl phenol Polycyclic quinones and ketones Aliphatic carboxylic acids Cs and C, dicarboxylic acids... 

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds... 

Britt, PR, A.C. Buchanan iii, and C.V. Owens Jr Eormation of nitrogen containing polycyclic aromatic hydrocarbons (aza-arenes) from the pyrolysis of Amadori componnds 55th Tobacco Science Research Conference, Program Booklet and Abstracts, Vol. 55, Paper No. 46, 2001, p. 48. 

Smoking is a slow process and it is not easy to control the process. Smoke contains phenolic compounds, adds, and carbonyls and smoke flavor is primarily due to the volatile phenolic compound [10,20,34]. Wood smoke is extranely complex and more than 400 volatiles have been identified [43]. Guillen and Manzanos [26] identified around 140 compounds in liquid smoke prepared from Thymus vulgaris wood. Polycyclic aromatic hydrocarbons are ubiquitous in the environment as pyrolysis products of organic matter. Their concentrations in smoked food can reach levels hazardous for human health, especially when the smoking procedure is carried out under uncontrolled conditions [46]. Wood smoke contains nitrogen oxides, polycyclic aromatic hydrocarbons, phenolic compounds, furans, carbonylic compounds, aliphatic carboxylic acids, tar compounds, carbohydrates. 

Polycyclic aromatic hydrocarbons were discussed in Chapter 21 (Section 21.8), and two important examples are naphthalene and anthracene. There are also important polycyclic systems that contain heteroatoms. These particular heterocycles are extremely important because they are found in many biological systems and in medicines. The discussion will focus only on polycyclic heterocycles that contain one or more nitrogen atoms because they are arguably the more important ones. 

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