The Nomenclature of Benzene Derivatives

The nomenclature of benzene derivatives is described in Sec. 4.6. Common names and structures to be memorized include those of toluene, styrene, phenol, aniline, and xylene. Monosubstituted benzenes are named as benzene derivatives (bromobenzene, nitrobenzene, and so on). Disubstituted benzenes are named as ortho- (1,2-), meta- (1,3-), or para- (1,4-), depending on the relative positions of the substituents on the ring. Two important groups are phenyl (C6H5-) and benzyl (C6H5CH2-). 

The nomenclature of benzene derivatives is similar to the nomenclature for saturated ring systems. If there is more than one substituent present, numbers are used to indicate substituent positions. For example, the compound... 

Many organic molecules contain a benzene ring with one or more substituents, so we must leam how to name them. Many common names are recognized by the lUPAC system, however, so this complicates the nomenclature of benzene derivatives somewhat. 

Solution All of these structures are derivatives of benzene. Hence, a consideration of the nomenclature of benzene derivations will aid in the drawing of these compounds. ... 

The Discovery of Benzene 627 Nomenclature of Benzene Derivatives 628 Reactions of Benzene 630 The Kekule Structure for Benzene 631 The Thermodynamic Stability of Benzene 632 Modern Theories of the Structure of Benzene 634 Huckel s Rule The 4n +2 tt Electron Rule 637 Other Aromatic Compounds 645... 

Chapter 21 discusses the concept of aromaticity as well as the nomenclature and the specialized chemical reactions of aromatic compounds such as benzene and its derivatives. This chapter comes late in the book, with the notion that the chemistry of aliphatic compounds is simply used more often. The acid-base theme is continued with the recognition that the fundamental substitution chemistry associated with benzene derivatives may be explained by the reaction of aromatic rings as Lewis bases or nucleophiles with electrophilic reagents. The reactions of benzene derivatives with strong bases and good nucleophiles are also presented. 

Consensus on nomenclature had been reached by the 1890s. Aniline was the parent of its derivatives, though sulfonic acids were considered derivatives of benzene, such as aminobenzenesulfonic acid. The prefix amino- was added to naphthalene and its derivatives. Many trivial names came into use, particularly for aminonaphthalenesulfonic acids, found in both academic and industrial research laboratories. Though IUPAC convention now numbers amino aryl compounds according to the parent hydrocarbon, the earlier system of numbering has often been retained, since some names include the positions of substituents at carbon atoms numbered according to the older systems. 

The Structure of Benzene 407 The Stability of Benzene 409 Bonding in Benzene 410 Substituted Derivatives of Benzene and Their Nomenclature 412 Polycyclic Aromatic Hydrocarbons 414 Fullerenes, Nanotubes, and Graphene 416-417 Physical Properties of Arenes 416... 

It IS hard to find a class of compounds in which the common names of its members have influenced organic nomenclature more than carboxylic acids Not only are the common names of carboxylic acids themselves abundant and widely used but the names of many other compounds are derived from them Benzene took its name from benzoic acid and propane from propionic acid not the other way around The name butane comes from butyric acid present m rancid butter The common names of most aldehydes are derived from the common names of carboxylic acids—valeraldehyde from valeric acid for exam pie Many carboxylic acids are better known by common names than by their systematic ones and the framers of the lUPAC rules have taken a liberal view toward accepting these common names as permissible alternatives to the systematic ones Table 19 1 lists both common and systematic names for a number of important carboxylic acids... 

When applying this principle to replacement names generated from fusion nomenclature, it is essential to keep in mind that fusion names for hydrocarbons ending in -cycloalkene are for fully unsaturated skeletons the -ene ending implies whatever number of double bonds may be necessary, without a multiplier. Thus (117) has six double bonds in the twelve-membered ring, and one must add ten hydrogens to saturate it to the stage of a simple benzene derivative, compound (118). 

Benzene derivatives. Tbe nomenclature is a combination of the lUPAC system and traditional names. Many of the derivatives are named by the substituent group appearing as the prefbt. These may be considered a subclass of the aliphatic-aromatic hydrocarbon family, which contains both aliphatic and aromatic units in its structures. Thus, alkylbenzenes are made up of a benzene ring and alkane units alkenylbenzenes are Composed of a benzene ring and alkene units and alkynylbenzenes comprise a benzene ring and alkyne units. Examples of alkylbenzenes include... 

In indole, benzimidazole, and their derivatives, all symmetry restrictions on the IPA and 2PA allowedness of transitions are lifted. In these molecules. La and Lb transitions are not formally defined. However, bands in the low-energy portion of the IPA and 2PA spectra can be assigned to transitions which have similar characteristics to the La and Lb transitions of benzene (although they are red-shifted with respect to benzene or toluene), so the nomenclature is often extended to these systems. 

A few words of clarification about the nomenclature are relevant here. Columnar phases have been known for many years they were evident, for example, in the work of Spegt and Skoulios (28) on metal soaps, although these are not classical disk-shaped molecules. In 1977, however, a hexasubstituted benzene derivative was reported (29), this derivative was the first example of a properly disk-like mesogen, and the term discotic was coined to describe the mesophases it formed. Thus, for example, the discotic hexagonal phase was labeled Dh- The introduction of this nomenclature has actually caused confusion as disk-like molecules are not alone in their capacity to form columnar phases (indeed, some... 

Aromatic" compounds are those derived from benzene and similar ring systems. As with aliphatic nomenclature described above, the process is determining the root name of the parent ring determining priority, name, and position number of substituents and assembling the name in alphabetical order. Functional group priorities are the same in aliphatic and aromatic nomenclature. See p. 676 for the list of priorities. 

Silver complexes have also been described for the cyclopropanation reaction. When using benzene, the use of Tp Ag(thf) (where Tp "" =hydrotris(3, 5-bis(trisfluoromethyl)pyrazolyl)borate for the rules of nomenclature of Tp" ligands see reE ) provided products derived from the addition of the carbene moiety to the arene ring (Scheme 7a), followed by ring expansion into a cycloheptatriene, in the... 

Solution This problem requires a knowledge of arene nomenclature. Benzene (CeHe) is the simplest aromatic hydrocarbon. Benzene compounds can be named as a derivative of benzene or as a phenyl-substituted compound. 

Most of the exohedral fullerene derivatives of preparative importance are formed by one or several formal 1,2-additions to [6,6]- or [5,6]-bonds. For a suitable discussion of the regiochemistry of such fullerene derivatives it is very valuable to introduce a simple and clear site labeling system, which allows facile description of the constitution of a given fullerene derivative. We first introduced a very descriptive nomenclature [177,188] for the assignment of the relative positional relationships (like ortho, meta and para in benzene chemistry) of addend carrying bonds in Cgg derivatives with labeling the corresponding bonds as cis-n (n = 1 -3), e, e", trans-n (n= 1-4) (Fig. 15). 

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