IUPAC systematic nomenclature

The accepted conventional nomenclature based on the cepham (the fused /3-lactam-perhydrothiazine system) is used throughout this chapter. Carbon atom bonded to C-3 has been numbered as C-10 (or C-3 ). Stereochemistry at C-7 is specified either as absolute configuration R/S, or as a//3 depending on the orientation of the substituent, below or above the plane, respectively. The above abbreviated common names and numbering for the cephalosporins should not be confused with the IUPAC systematic nomenclature as used by Chemical Abstract, which, for example, designates 7-ACA as (6/3,7/3)-3-(acctoxymcthyl)-7-amino-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid. 

It is extremely difficult to maintain uniform nomenclature or abbreviations for these molecules due to the diverse nature of the saccharide moiety and the continual discovery of new glycosphingolipids. A semi-systematic nomenclature for glycosphingolipids has been recommended by the IUPAC-IUB Commission on Biochemical Nomenclature,7 and has been reviewed in some detail.8-10 Readers are urged to consult these articles in order to become familiar with the no-... 

Another type of anion, confined for practical purposes to boron compounds, has no unshared electrons at the anionic site, and must be thought of as being formed by addition of hydride to a boron atom (or other atom with an incomplete valence shell). Such structures were not anticipated at the time general heterocyclic nomenclature was developed, and they are only recently being fitted into systematic nomenclature (IUPAC Provisional Recommendation 83.2). Proposals for a suffix to indicate such structures are under consideration (1982). 

We will base our study on the system developed by the International Union of Pure and Applied Chemistry. The system is called the IUPAC Rules. There are other semi-systematic nomenclature systems, and many individual compounds are known by nonsystematic or trivial names. These names will be given along with the IUPAC names when such trivial names are commonly used. 

The names cited are common names, which have been in widespread use for a long time and are acceptable in IUPAC nomenclature. We will introduce the systematic nomenclature of these ring systems as needed in later chapters. 

Systematic nomenclature (Section 2.11) Names for chemical compounds that are developed on the basis of a prescribed set of rules. Usually the IUPAC system is meant when the term systematic nomenclature is used. 

The systematic nomenclature for the cycloproparenes is confused because the fusion rule (IUPAC Rule A 21.3) requires that at least two rings of five or more members be present before the prefix cyclopropa may be used. Thus while l//-cyclopropa[a]- and -[/ naphthalene are correct for 10 and 11, respectively, 1 //-cyclopropabenzene is incorrect for 1. The Chemical Abstracts service and IUPAC are unanimous in naming 1 as bicyclo-[4.1. Ojhepta-1,3,5-triene la. Thus if the parent member is strictly named, not only does it differ from that of its higher homologues, but also it could be taken to imply a bond localized structure. Throughout this chapter parent 1 and its derivatives 5-9 are referred to as cyclopropabenzenes and numbered as shown for structure 1. 

Systematic nomenclature on a worldwide scale began in 1892 when a committee of the International Chemical Congress established a set of standards known as the Geneva Rules for naming organic compounds. The International Union of Pure and Applied Chemistry (ILTPAC) http /Ywww,iupac.org/dhtml home.html was formed in 1919 and further developed this nomenclature system. In 1886 in the United States, the American Chemical Society (ACS) established a Committee on... 

Hydrocarbons, esters, etc., which have one or more hydrogen atoms replaced by a halogen atom are named so that the substituents have the lowest possible numbers. When multiple functions are present, they are numbered according to precedences established by IUPAC or CAS nomenclature rules. Both trivial and systematic nomenclatures are used. 

The rigorous and systematic nomenclature addressed by 1UPAC (14), in which all atoms and their topological connections are defined unambiguously, is too complicated here. Thus we use traditional names. But the semi-systematic nomenclature accepted by IUPAC (75) is mentioned briefly. 

Figure 5.5.12-1 Alternate nomenclatures for the retinoids associated with vision. A the Karrer based nomenclature adopted by the IUPAC. B the systematic nomenclature proposed by Frickel and others. C a second systematic nomenclature found in the literature. D the modified pictograph of the IUPAC nomenclature used in this work.

In most existing inventories, chemical identities are standardized through the use of CAS numbers, molecular formulas (chemicals with discrete structures), and IUPAC (International Union of Pure and Applied Chemistry) systematic nomenclature. Chemicals of unknown or variable composition, complex reaction products, and biological materials (UVCB), are usually listed alphabetically under subheadings or by definition.14 Some of the countries that have compiled various inventories include Australia, Canada, EU, Japan, Philippines, South Korea, and United States. 

Union of Pure and Applied Chemists (IUPAC) has developed systematic nomenclature rules for polymers. As is the case with many small-molecule organic compounds, the IUPAC names are often complex and cumbersome. Therefore, polymer scientists often use common or abbreviated names, sometimes even product names. Poly[l- methoxycarbonyl)-l-methylethylene] (IUPAC) is almost always referred to as poly(methyl methacrylate), or PMMA, or even Lucite. IUPAC discourages the use of trademarked names, however unless it is importanfto refer to a specific commercial product. The IUPAC Macromolecular Nomenclature Commission recognizes a number of trivial names for common polymers (Metanomski 1999). 

Although the formulation of a systematic nomenclature in line with existent IUPAC nomenclature was included in the 1990 Recommendations [3], serious problems still abound. This is recognized by their statement [4]... 

IUPAC names use the more complex alkyl group as the root name, and the rest of the ether as an alkoxy group. For example, cyclohexyl methyl ether is named methoxycyclohexane. This systematic nomenclature is often the only clear way to name complex ethers. 

Nomenclature The most recent IUPAC nomenclature is stressed throughout the book, but common nomenclature is also discussed and used to develop students familiarity. Teaching only the IUPAC nomenclature might be justifiable in theory, but such an approach would handicap students in their further study and use of the literature. Much of the literature of chemistry, biology, and medicine uses common names such as methyl ethyl ketone, isovaleric acid, methyl tert-butyl ether, -y-aminobutyric acid, and e-caprolactam. This book emphasizes why systematic nomenclature is often preferred, yet it encourages familiarity with common names as well. 

Names like this are fine for familiar compounds that are widely used and referred to by chemists, biologists, doctors, nurses, perfumers alike. But there are over 16 million known organic compounds. They can t all have simple names, and no one would remember them if they did, For this reason, the IUPAC (International Union of Pure and Applied Chemistry) have developed systematic nomenclature, a set of rules that allows any compound to be given a unique name that can be deduced directly from its chemical structure. Conversely, a chemical structure can be deduced from its systematic name. 

Rule-based or systematic nomenclature (e.g., International Union of Pure and Applied Chemistry [IUPAC] or CAS nomenclature) is based on a set of linguistic rules that apply to its structure. For example, the IUPAC and CAS names for mandelic acid are 2-phenyl-2-hydroxyacetic acid and benzeneacetic acid, a-hydroxy-, respectively. The number of possible systematic names is practically endless. A small, but not nearly exhaustive, set of other systematic names includes phenylglycolic acid, phe-nylhydroxyacetic acid, ( )-a-hydroxybenzeneacetic acid, ( )-a-hydroxyphenylacetic acid, ( )-2-hydroxy-2-phenylethanoic acid, ( )-Mandelic acid, (RS)-Mandelic acid, DL-Amygdalicacid,DL-Hydroxy(phenyl)aceticacid,DL-mandelicacid,paramandelic acid, a-hydroxy- a-toluic acid, a-hydroxyphenylacetic acid, a-hydroxybenzeneacetic... 

Newly discovered elements may be referred to in the scientific literature but until they have received permanent names and symbols from IUP AC, temporary designators are required. Such elements may be referred to by their atomic numbers, as in element 120 for example, but IUPAC has approved a systematic nomenclature and series of three-letter symbols (see Table II).2... 

IUPAC IUB nomenclature recommendations (1983), reproduced in full in Amino Acids, Peptides, and Proteins, 1985, Vol. 16, The Royal Society of Chemistry, p. 387 and in Eur.J.Biochem., 1984,138, 9, encourage the retention of trivial names for the common a-amino acids, but systematic names are relatively straightforward thus, L-alanine is 2S-aminopropanoic add and L-histidine is 2S-amino-3-(imidazol-4-yl)-propanoic add (the name for the predominant tautomer). 

Systematic nomenclature Nomenclature following IUPAC or Chemical Abstracts rules to reflect a molecule s structure. 

As the science of organic chemistry slowly grew in the 19th century, so too did the number of known compounds and the need for a systematic method of naming them. The system of nomenclature we ll use in this book is that devised by the International Union of Pure and Applied Chemistry (IUPAC, usually spoken as eye-you-pac). 

Chlorophyll a, the green photosynthesis pigment, is the prototype of the chlorin (2,3-dihydro-porphyrin) class of products. It was first isolated by Willstatter1 at the turn of the century. The common structural unit in this class is the chlorin framework named after chlorophyll. The chromophore with a partially saturated pyrrole ring, which is formally derived from the completely unsaturated porphyrin, is less symmetric than the latter and systematically named according to IUPAC nomenclature as 2,3-dihydroporphyrin. 

The bacterioehlorin structural-type is formally derived from porphyrin by saturation of two peripheral C —C double bonds in oppposite pyrrole rings and therefore systematically named according to IUPAC nomenclature as 7,8,17,18-tetrahydroporphyrin. 

The replacement of an electrofugic atom or group at a nucleophilic carbon atom by a diazonium ion is called an azo coupling reaction. By far the most important type of such reactions is that with aromatic coupling components, which was discovered by Griess in 1861 (see Sec. 1.1). It is a typical electrophilic aromatic substitution, called an arylazo-de-hydrogenation in the systematic IUPAC nomenclature (IUPAC 1989c, see Sec. 1.2). 

The majority of the names for chemicals in this alphabetically arranged index conform to one of the systematic series permitted under various sections of the IUPAC Definitive Rules for Nomenclature. Where there is a marked difference between these names and the alternative names recommended in the IUPAC-based BS2472 1983 or ASE 1985 nomenclature lists, or long established traditional names, these are given as synonyms in parentheses after the main title. These synonyms also have their own index entry, cross-referenced back to the IUPAC-based names used as bold titles in the text of Volume 1. 

Some of the rigidly systematic names selected by the Association for Science Education for their nomenclature list in 1985 from the IUPAC possibilities, and some of the systematic indexing names used by Chemical Abstracts since 1972, are given as synonyms in the Index of Chemical Names (Appendix 4). This should assist those coming into industry and research with a command of those nomenclature systems but who may be unfamiliar with the current variety of names used for chemicals. The inclusion where possible of the CAS Registry Number for each title compound should now simplify the clarification of any chemical name or synonym problems, by reference to the Registry Handbook or other CAS source. 

According to the IUPAC-IUB Enzyme Nomenclature,11 pectinesterase belongs to the carboxyl ester hydrolases (EC 3.1.1.11) and has the systematic name pectin pectyl-hydrolase. The literature also contains the expressions pectin methylesterase, pectin demethoxylase, and pectin methoxylase for the same enzyme. The old name pectase,... 

All enzymes already mentioned, except oligo-D-galactosiduronate hydrolase, are included in the Enzyme Nomenclature of the IUPAC-IUB Enzyme Commission,11 and their code numbers and suitably modified, systematic names are used herein. 

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