Nomenclature Naming Compounds

The systematic lUPAC nomenclature of compounds tries to characterize compounds by a unique name. The names are quite often not as compact as the trivial names, which are short and simple to memorize. In fact, the lUPAC name can be quite long and cumbersome. This is one reason why trivial names are still heavily used today. The basic aim of the lUPAC nomenclature is to describe particular parts of the structure (fi agments) in a systematic manner, with special expressions from a vocabulary of terms. Therefore, the systematic nomenclature can be, and is, used in database systems such as the Chemical Abstracts Service (see Section 5.4) as index for chemical structures. However, this notation does not directly allow the extraction of additional information about the molecule, such as bond orders or molecular weight. 

Nomenclature. The compound on which the enzyme acts is known as the substrate. The name of the enzyme is now usually obtained by adding the termination ase to the name of the substrate. Thus an enzyme which hydrolyses an ester is known as an esterase. Nevertheless the older names of many enzymes still persist owing to their early disco ieiy. In some cases the name of the enzyme indicates the reaction w hich it catalyses, e.g. oxidase. 

Halogen Derivatives. Using substitutive nomenclature, names are formed by adding prefixes listed in Table 1.8 to the name of the parent compound. The prefix perhalo- implies the replacement of all hydrogen atoms by the particular halogen atoms. 

UPAC system of nomenclature (Section 3.4) Rules for naming compounds, devised by the International Union of Pure and Applied Chemistry. 

There it is. A lot of rules. No one ever said nomenclature would take 10 minutes to learn, but with enough practice, you should get the hang of it. Let s now take everything we have learned and practice naming compounds ... 

The naming of these three heterocyclic fused (5 5 5) ring systems has been carried out according to the IUPAC system of nomenclature. Some examples are given as follows compound la (Table 1) is named (3-hydroxy-4-methoxyphenylthieno[2,3-3]pyrrolizin-8-one. Compound 15a (Table 2) is dithieno[3,2-3 2, 3 - 1thiophene. Compound 23a (Table 2) is dithieno[3,2-3 2, 3 - 1pyrrole. Compound 20a (Table 2) is dithicno[3,2-3 2, 3 -r/]thiophene-4,4-dio ide. Compound 13b (Table 2) is 3,4-dimethyldithieno[3,2-3 2, 3 -i/]thiophene-7,7-dioxide. Compound 38 (Table 4) is fM, r, r-10-azatricyclo[5.2.1.01 10]deca-2,5,8-triene. Compound 39 (Table 4) is cis,cis, m-10-azatricyclo[5.2.1.01 10]deca-2,8-diene. The nomenclature of compound 40 (Table 4) is 1,4,7 triaza tricy-clo[5.2.1.01,10]decane. 

Nomenclature is the term referring to the naming of compounds. In this section, we will investigate how to name inorganic compounds. We will see how to name organic compounds in Chapter 21. In order to name compounds correctly, you will need to memorize certain elements and ions, and you will need to apply a few rules. 

Specialists in nomenclature recognise two different categories of nomenclature. Names that are arbitrary (including the names of the elements, such as sodium and hydrogen) as well as laboratory shorthand names (such as diphos and LithAl) are termed trivial names. This is not a pejorative or dismissive term. Trivial nomenclature contrasts with systematic nomenclature, which is an assembly of rules, themselves arbitrary. The function of specialists in nomenclature is to codify such rules so that everyone can use them to identify pure substances, rather like many of us use an alphabet to represent words. There may be more than one way to name a compound or species, and no one way may be superior to all the others. Names also vary in complexity, depending upon how much information needs to be conveyed. For example, a compositional name conveys less information than a structural (or constitutional) name, because this includes information about the arrangement of atoms in space. 

Atoms rarely exist as individual units. Atoms combine with each other to produce the familiar substances of everyday life. Chemistry is largely the study of how atoms combine to form all the different forms of matter. The reason atoms combine involves the subject of chemical bonding, which is explored in Chapter 7. In this chapter, the grouping of atoms into different types of compounds is examined. In the first half of the chapter, chemical nomenclature is discussed. Some of the basic rules for naming compounds are presented. Atoms combine and are rearranged through chemical reactions. The last half of the chapter examines the basic process of chemical reactions and classifies several different types of reactions. 

Two older systems of nomenclature name aliphatic azo compounds diazenes or diimines, as in structure VII. 

IUPAC - standard guidelines for naming compounds Nomenclature Strategy - find longest carbon chain, identify and note location of functional groups and substituents by chain position number. 

IUPAC nomenclature names ethers as alkoxy alkanes, alkoxy alkenes, or alkoxy alkynes. The group in the chain that has the greatest number of carbon atoms is designated the parent compound. In the case of aromatic ethers, the benzene ring is the parent compound. 

Furthermore, the use of special subgroup names such as fenchenes, which applies to a series of synthetic compounds to indicate their derivation from fenchyl and iso-fenchyl derivatives and reportedly (33) to distinguish them from closely related naturally occurring terpenes, obviously complicates the problem of systematizing nomenclature. Names such as cyclofenchene and /8-difenchene are two additional memory exercises. Such irregularities in nomenclature have, of course, been carried over into the nomenclature of derivatives of these bicyclic hydrocarbons. 

The modem system of nomenclature uses ONs directly in naming compounds. Thus in FeO and Fe203,... 

An example of the systematic nomenclature for compounds in this group is cyclobuta[l,2-Z> 3,4-//jdipyridine in this review this compound will be named as an aza analogue of biphenylene, that is, 1,8-diazabiphenylene. The only structural types found in the literature are those described below although there seems no reason why other variants are unknown. No record of unsuccessful attempts at synthesis were revealed. 

So far, we have just looked at hydrocarbons that are straight chains. There are many compounds where central carbon atoms are bonded to three or four carbon atoms or other non-hydrogen atoms. For branched-chain hydrocarbons, there are special procedures for naming compounds. To start with, we will only consider saturated hydrocarbons. Once you understand some of the basic rules of nomenclature, we can begin to look at unsaturated hydrocarbons and atoms other than carbon and hydrogen. 

The point of naming a compound is to be able to communicate with other chemists. Most chemists are happiest communicating chemistry by means of structural diagrams, and structural drawings are far more important than any sort of chemical nomenclature. That s why we explained in detail how to draw structures, but only gave an outline of how to name compounds. Good diagrams are easy to understand, quick to draw, and difficult to misinterpret. 

When writing a chemical formula, you learned that you write the metal element first. Similarly, the metal comes first when naming a chemical compound. For example, sodium chloride is formed from the metal sodium and the non-metal chlorine. Think of other names you have seen in this chapter, such as beryllium chloride, calcium oxide, and aluminum oxide. In each case, the metal is first and the non-metal is second. In other words, the cation is first and the anion is second. This is just one of the rules in chemical nomenclature the system that is used in chemistry for naming compounds. 

The International Union of Pure and Applied Chemistry (IUPAC) was formed in 1919 by a group of chemists. The main aim of IUPAC was to establish international standards for masses, measurement, names, and symbols used in the discipline of chemistry. To further that aim, IUPAC developed, and continues to develop, a consistent and thorough system of nomenclature for compounds. 

IUPAC-like expressions, true IUPAC nomenclature names, and InChl and SMILES representations of chemical compounds are well suited for detection by machine learning approaches. Conditional random fields (CRFs)41 and support vector machines have been used for the detection of IUPAC expressions in scientific literature 42 Other approaches are based on rules sets43 44 or combinations of machine learning with rule-based approaches 45 All these approaches have in common that they face one significant problem the name-to-structure problem. 

The three-dimensional structure is the most unique description of a chemical compound. That is why chemical entities should be compared on the basis of their structure as represented in a connection table, not on their common or nomenclature name. Comparison of structures, however, requires that mentions of chemical entities in text are translated into connection tables this is typically done by name-to-structure (N2S) tools. On a conference on chemical information in Sitges (International Chemistry Information Conference [ICIC]) 2007), preliminary data on attempts at benchmarking N2S tools were reported 46 Although this analysis is preliminary and care should be taken to avoid drawing conclusions that are not supported by the analysis, these data suggest that the N2S tools currently available are correctly converting only between 30% and 50% of all named entities. 

The nomenclature of compounds listed in this index follows the usage of the authors of the chapters and not necessarily the strict lUPAC or Chemical Abstracts style. However, when a chemical name as used by the authors is widely divergent from accepted usage, the more appropriate name has been marked with an asterisk to alert the user that the index entry may not appear in the text on the page indicated. To keep entries brief, "obvious" details, such as indicated hydrogen in its usual or only possible place, have been omitted. 

Carbohydrate nomenclature impacts on stereochemistry, and on the nomenclature of compounds other than mainstream carbohydrates (e.g., hydroxylactones), often named as modihed carbohydrates in Chemical Abstracts Service (CAS) and elsewhere. For further stereochemical information on carbohydrates, see Chapter 7. 

Systematic Nomenclature.—That compound which by synthesis or decomposition is shown to have the structure represented by the straight chain formula is always known as the normal. In strictly systematic nomenclature this name is often omitted, but implied, so... 

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