Heterocyclic hydrocarbons compounds

The term dioxin refers to a class of heterocyclic hydrocarbons compounds used in various industrial processes, such as paper manufacture and waste incineration. They readily pass into and accumulate in living systems. Animal experiments have demonstrated that these chemicals can produce mutations and fetal malformations. They have also been implicated as human carcinogens. 

Alkali metal reduction is a widely employed method for the preparation of radicals derived from various classes of conjugated compounds such as hydrocarbons, heterocycles, nitro compounds, quinones, and nitriles. For... 

Heterocyclic aromatic compounds a. Pyridine and other azabenzenes. The azabenzenes, compounds in which — N= groups replace —CH= groups, often bear remarkable chemical spectroscopic similarities to the parent homooyclic hydrocarbons. This is associated with their being 7r-isoelectronic with them. 

A mammal may emit many volatile compounds. Humans, for instance, give off hundreds of volatiles, many of them chemically identified (Ellin etal., 1974). The volatiles include many classes of compound such as acids (gerbil), ketones, lactones, sulfides (golden hamster), phenolics (beaver, elephant), acetates (mouse), terpenes (elephant), butyrate esters (tamarins), among others. The human samples mentioned before contained hydrocarbons, unsaturated hydrocarbons, alcohols, acids, ketones, aldehydes, esters, nitriles, aromatics, heterocyclics, sulfur compounds, ethers, and halogenated hydrocarbons. Sulfur compounds are found in carnivores, such as foxes, coyotes, or mustelids. The major volatile compound in urine of female coyotes, Canis latrans, is methyl 3-methylhut-3-enyl sulfide, which accounts for at least 50% of all urinary volatiles (Schultz etal, 1988). 

Types of compounds are arranged according to the following system hydrocarbons and basic heterocycles hydroxy compounds and their ethers mercapto compounds, sulfides, disulfides, sulfoxides and sulfones, sulfenic, sulfinic and sulfonic acids and their derivatives amines, hydroxylamines, hydrazines, hydrazo and azo compounds carbonyl compounds and their functional derivatives carboxylic acids and their functional derivatives and organometallics. In each chapter, halogen, nitroso, nitro, diazo and azido compounds follow the parent compounds as their substitution derivatives. More detail is indicated in the table of contents. In polyfunctional derivatives reduction of a particular function is mentioned in the place of the highest functionality. Reduction of acrylic acid, for example, is described in the chapter on acids rather than functionalized ethylene, and reduction of ethyl acetoacetate is discussed in the chapter on esters rather than in the chapter on ketones. 

In our discussion of the Hammett correlation, we have confined ourselves mostly to benzene derivatives. Of course, a similar approach can be taken for other aromatic systems, such as for the derivatives of polycyclic aromatic hydrocarbons and heterocyclic aromatic compounds. For a discussion of such applications, we refer to... 

Hydrocarbons. The hydrocarbons, as the name implies, are compounds containing carbon and hydrogen. If the carbon atoms lie in the same plane they are known as open-chain, or aliphatic hydrocarbons. If the carbon atoms form a ring structure they are known as cyclic hydrocarbons. The cyclic hydrocarbons are further differentiated into benzene benzenoid, or aromatic) and alicydic hydrocarbons. If there is another element present in the ring besides carbon, they are known as heterocyclic hydrocarbons. 

Organochlorine insecticides are chlorinated hydrocarbon compounds that fall into three basic structure classifications aryl (aromatic), carbocyclic, and heterocyclic. 

The Maillard reaction and the oxidation of lipids are two of the most important reactions for the formation of aromas in cooked foods. Interactions between lipid oxidation and the Maillard reaction have received less attention, despite the fact that lipids, sugars, and amino acids exist in close proximity in most foods. Lipids, upon exposure to heat and oxygen, are known to decompose into secondary products, including alcohols, aldehydes, ketones, carboxylic acids, and hydrocarbons. Aldehydes and ketones produce heterocyclic flavor compounds reacting with amines and... 

Stabilization Energies of Nonalternant Hydrocarbons and Heterocyclic Aromatic Compounds (in kcal mol 1)... 

The chemical reactivity of simple heterocyclic aromatic compounds varies widely in electrophilic substitution reactions, thiophene is similar to benzene and pyridine is less reactive than benzene, while furan and pyrrole are susceptible to polymerization reactions conversely, pyridine is more readily susceptible than benzene to attack by nucleophilic reagents. These differences are to a considerable extent reflected in the susceptibility of these compounds and their benzo analogues to microbial degradation. In contrast to the almost universal dioxygenation reaction used for the bacterial degradation of aromatic hydrocarbons, two broad mechanisms operate for heterocyclic aromatic compounds ... 

By analogy with their ability for biotransformation of PAHs, fungi are capable of carrying out a number of transformations of heterocyclic aromatic compounds though—as for the hydrocarbons—these do not generally result in the total degradation of the substrate. 

Six-Membered Heterocyclic Aromatic Compounds When a CH group in an aromatic hydrocarbon is replaced by =N, there is very little change in the spectrum, except for a slight intensification of the... 

According to Meerwein and others,323,516 use of boron trifluoride may be valuable, since it forms well-defined molecular compounds with simple aliphatic carboxylic acids for example, aromatic and heterocyclic hydrocarbons and aryl ethers can be acetylated smoothly and in good yield by acetic anhydride and boron trifluoride.323 The preparation of boron trifluoride has been described by Krause and Nitsche and by Booth and Willson.517... 

Van Duuren, B.L. The fluorescence spectra of aromatic hydrocarbons and heterocyclic aromatic compounds ... 

Other kinds of aromatic eom])ounds exist besides simple benzene derivatives. Two common types will be covered in this chapter polycyclic fused benzenoid hydrocarbons and other cyclic conjugated polyenes with either more or less than six carbons in the ring. In Chapter 25, a third common class, heterocyclic aromatic compounds, will be pre.sented. 

Polycyclic organic matter, derived from the total exhaust emission, is an extremely complex mixture. It includes a large number of compounds such as polynuclear aromatic hydrocarbons (PAH), derivations of PAH such as nitro-PAH and amino-PAH, oxygenated PAH such as phenols and quinones, and heterocyclic aromatic compounds containing sulfur and oxygen. In order to assist in the identification of classes of toxic compounds it is possible to fractionate the exhaust emissions into vapor and... 

Subsequendy, the aromaticity concept built on carbocydes has been applied successfully to heterocyclic organic compounds, i.e., to a family of aromatic compounds which contain one or more heteroatoms as a part of their cyclic TC-electron system. However, some of the measures developed for aromatic hydrocarbons, particularly those based on geometrical parameters, have been modified to be used for heterocycles (1993JCI70, 2001T5715, 2010SY1485). 

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