Nomenclature common prefixes

Nomenclature based on a parent term with an appended suffix accounts for most natural product names. However, as related compounds are identified, or even when a suffix has to denote multiple functional groups, a variety of modifying terms can be employed. For example, the common prefix nor- denotes the removal of a skeletal atom from the parent structure the loss of two or more skeletal atoms is indicated by combining an appropriate numerical prefix with nor- , e.g., dinor- , trinor- (Giles 1999). Table 1.2 lists additional examples of commonly encountered modifying terms. 

Having introduced the most common prefix of IUPAC inorganic nomenclature, (p) in the previous example, another "typical" inorganic coordination compound, Fe2(CO)9, is presented as Figure 20. The names assigned to this compound are ... 

In common nomenclature, the prefix heto- indicates the presence of a ketone carbonyl in a substituted carboxylic acid (as illustrated by the common name /3-ketobutyric acid) ... 

The heterocycloalkanes can be named using cycloalkane nomenclature. The prefix aza- for nitrogen, oxa- for oxygen, thia- for sulfur, and so forth, indicates the heteroatom. Other systematic and common names abound in the literature, particularly for the aromatic heterocycles. 

The common method of naming aldehydes corresponds very closely to that of the related acids (see Carboxylic acids), in that the term aldehyde is added to the base name of the acid. For example, formaldehyde (qv) comes from formic acid, acetaldehyde (qv) from acetic acid, and butyraldehyde (qv) from butyric acid. If the compound contains more than two aldehyde groups, or is cycHc, the name is formed using carbaldehyde to indicate the functionaUty. The lUPAC system of aldehyde nomenclature drops the final e from the name of the parent acycHc hydrocarbon and adds al If two aldehyde functional groups are present, the suffix -dialis used. The prefix formjlis used with polyfunctional compounds. Examples of nomenclature types are shown in Table 1. 

The two most commonly applied systems for naming polycyclic parents are in some ways complementary. Fusion nomenclature provides names for structures containing the maximum number of non-cumulative double bonds von Baeyer nomenclature (Section 1.02.3.4) names fully saturated structures. Thus names for partially hydrogenated structures can be arrived at either by adding hydro prefixes to fusion names or ene , diene , etc. suffixes to von Baeyer names (see examples 29 and 30). If needed, rules are available for... 

Both common and systematic names of compounds are used throughout this volume, depending on which the Editor-in-Chief feels is most appropriate. Preparations appear in the alphabetical order of names of the compound or names of the synthetic procedures. The Chemical Abstracts indexing name for each title compound, if it differs from the title name, is given as a subtitle. Because of the major shift to new systematic nomenclature adopted by Chemical Abstracts in 1972, many common names used in the text are immediately followed by the bracketed, new names. Whenever two names are concurrently in use, the carre CChemical Abstracts name is adopted. The prefix n- is deleted from -alkanes and w-alkyls. All reported dimensions are now expressed in S st me International units. 

Older texts often employ an alternative nomenclature in which the suffixes -ous and -ic are encountered. In general, these labels only apply to the most common oxidation states of the metals, -ic referring to the higher oxidation state and -ous to the lower. Using this nomenclature, copper(ii) is referred to as cupric and copper(i) as cuprous. The system works well if there are only two common oxidation states for a metal ion, but if there are more, the scheme becomes either ambiguous or unwieldy as a variety of prefixes are added. 

Forgetting to use prefixes is a common mistake that students make in the midst of an exam. Make sure you indicate the appropriate stereochemistry in your nomenclature, especially if your instructor takes time to indicate the specific stereochemistry of a compound. Again, get into the habit of doing this when you re working on homework exercises. 

Steroids are compounds possessing the tetracyclic skeleton of cyclopenta[a]phenan-threne (1) or a skeleton derived therefrom by one or more bond scissions or ring expansions or contractions. Natural steroids have trivial names. The nomenclature of steroids is not based on these trivial names, but on a few stereoparent hydrides that are common to many compounds. Substitutive nomenclature is used to designate characteristic groups and unsaturation. Structural modifications are expressed by appropriate non-detachable prefixes. 

Throughout this article, the heteroring will be referred to as either piperazine-2,5-dione or occasionally as cyclodipeptide. The earlier practice of referring to the ring as diketopiperazine has been avoided. The numbering of the piperazinedione ring is as shown in (1). In the cyclodipeptide nomenclature, the common three-letter code for the two amino acids, with the necessary prefix to indicate absolute configuration, will be used. 

In general, organic compounds are given systematic names by using the order prefix-parent-suffix, where prefix indicates how many branching groups are present, parent indicates how many carbons are in the longest chain and suffix indicates the name of the family. Common names as weU as systematic names are used for alkanes and their derivatives. However, it is advisable to use systematic names or the lUPAC (International Union of Pure and Applied Chemistry) nomenclature, which can be derived from a simple set of rules. 

In the common nomenclature for ethers, each of the R groups in R—O—R is named as a separate word, except when the groups are identical, in which case the prefix di or bis may be used (di is used for simple groups, bis for substituted groups) ... 

The word amine is derived from ammonia, and the class of compounds known as amine s therefore are commonly named as substituted ammonias. In this system, primary amines, having only one substituent on nitrogen, are named with the substituent as a prefix. More systematic nomenclature appends -amine to the longest chain, as for alcohols ... 

The position of the substituents is given according to IUPAC nomenclature using the prefixes 1-, 3-, and 5-. Formazans unsubstituted in the 1- and 5-positions and 1,5-dialkyl-substituted formazans are unknown. Aryl or heteroaryl groups are the most common 1,5-substituents. The 3- or meso position can be occupied by a variety of substituents (e.g., aryl, heteroaryl, H, OH, SR, halogen, N02, CN, and alkyl). 

Aldehydes, acids, and esters have roots for one and two carbons that are usually form- and acet-, rather than meth- and eth-, because these prefixes had been used so long they were grandfathered into the naming system (formaldehyde and acetic acid, rather than methanal and ethanoic acid). Departures from IUPAC nomenclature often occur for very common substances and, fortunately, they rarely can be misunderstood (ethyl alcohol instead of ethanol). 

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