Trivial nomenclature

Nomenclature, Trivial name = epichlorohydrin (ECH) ASTM name = chloromethyloxirane (CO) 1UPAC name = oxy(chloromethyl) ethylene. 

In the present state of organic chemical nomenclature trivial names are absolutely indispensable. Examples in support of this assertion are plentiful what should we do without names like glucose, saccharose, streptomycin, penicillin, quinine, and strychnine It is out of the question that in this respect the situation will become different in the near future, and it seems justifiable to question whether trivial names will ever be abandoned. 

Enzymes are classified in terms of the reactions which they catalyse and were formerly named by adding the suffix ase to the substrate or to the process of the reaction. In order to clarify the confusing nomenclature a system has been developed by the International Union of Biochemistry and the International Union of Pure and Applied Chemistry (see Enzyme Nomenclature , Elsevier, 1973). The enzymes are classified into divisions based on the type of reaction catalysed and the particular substrate. The suffix ase is retained and recommended trivial names and systematic names for classification are usually given when quoting a particular enzyme. Any one particular enzyme has a specific code number based upon the new classification. 

In chemistry, chemical structures have to be represented in machine-readable form by scientific, artificial languages (see Figure 2-2). Four basic approaches are introduced in the following sections trivial nomenclature systematic nomenclature chemical notation and mathematical notation of chemical structures. 

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. 

Neither a trivial name nor the systematic nomenclature, which both represent the structure as an alphanumerical (text) string, is ideal for computer proccs.sing. The reason is that various valid compound names can describe one chemical structure (Figure 2-6). As a consequence, the name/structure correlation is unambiguous but not unique. Nowadays, programs can translate names to structures, and. structitrcs to names, to make published structures accessible in electronic journals (see also Chapter (I, Section 2 in the Handbook). 

While the trivial and trade nomenclature in most cases has accidental character, the lUPAC Commission has worked out a series of rules [4] which allow the great majority of structures to be represented uniformly, though there still exists some ambiguity within this nomenclature. Thus, many structures can have more than one name. It is important that the rules of some dialects of the lUPAC systematic nomenclature are transformed into a program code. Thus, programs for generating the names from chemical structures, and vice versa (structures from names) have been created [5] (see Chapter II, Section 2 in the Handbook). 

Trivial nomenclature (Section 2 11) Term synonymous with common nomenclature... 

The latter nomenclature is always used for amino acids with trivial names. 

Complex linear polyamines are best designated by replacement nomenclature. These trivial names are retained aniline, benzidene, phenetidine, toluidine, and xylidine. 

Several systems of nomenclature have been used for naphthalene, and many trivial and trade names are well estabUshed. The Chemicaly hstracts Index Guide is employed in this article. The numbering of the naphthalene nucleus is shown in (1) older practices are given in (2) and (3). 

In the days of alchemy and the phlogiston theory, no system of nomenclature that would be considered logical ia the 1990s was possible. Names were not based on composition, but on historical association, eg, Glauber s salt for sodium sulfate decahydrate and Epsom salt for magnesium sulfate physical characteristics, eg, spirit of wiae for ethanol, oil of vitriol for sulfuric acid, butter of antimony for antimony trichloride, Hver of sulfur for potassium sulfide, and cream of tartar for potassium hydrogen tartrate or physiological behavior, eg, caustic soda for sodium hydroxide. Some of these common or trivial names persist, especially ia the nonchemical Hterature. Such names were a necessity at the time they were iatroduced because the concept of molecular stmcture had not been developed, and even elemental composition was incomplete or iadeterminate for many substances. 

The practice of assigning ad hoc names to organic compounds was neither avoidable, nor burdensome when only a small number of compounds were recognized. Such ad hoc names are termed "trivial" or "traditional," to indicate that they contain no encoded stmctural information. They are useful for common compounds, and many of them are retained to this day, but they are not helpful in understanding chemical relationships. As they proliferated, the number and variety of them became unmanageable. The development of systematic nomenclature was driven by this circumstance, and was made possible by advances in understanding and determining the stmcture of molecules. 

In 1981, the lUPAC-IUB Joint Commission on Biochemical Nomenclature proposed that there be a set of trivial names for the important vitamin D compounds, including calciol [67-97-0] for vitaminD, calcidiol [19356-17-3] ion 25-hydroxy-vitaminD, and calcitriol [32222-06-3] ion 1 a,25-dihydroxy-vitamin D. This nomenclature has met with varying degrees of acceptance, as has the proposal to use calcine [69662-75-5] (deoxy-vitamin D2) and ercalcine [68323-40-0] (deoxy-vitamin D ) to name the triene hydrocarbon stmcture for 9,10-j (9-cholesta-5,7,10(19)-ttiene and... 

Present-day nomenclature is partly the result of the conflict and interplay of two functions the need to communicate in speech and on the printed page on the one hand, and the need for archival storage of information and its efficient, reliable retrieval. The former function came first, and laid the basis for the nomenclature most commonly used even today, and gave birth to a wealth of trivial names (i.e. names that give little or no information on structure). These were often coined on the basis of the origin of the substance, as in the case of collidine, obtained from distillation of bones in glue factories, or were derived from a special characteristic, as in the case of skatole, which has a fecal odor. Such names are short and generally euphonious, but they must be memorized they cannot be deduced from the structure. 

Many names in common use for heteropolycycles provide little or no information about structure. Most such names were introduced long before any serious attempts were made to systematize nomenclature, and although more systematic equivalents can now be coined in many cases (for example, indole can be named benz[f)]azole or 1-azacyclopentabenzene), it is likely that the use of a substantial residue of trivial names will continue. However, one would not expect many new trivial names to be introduced in the future, except in the natural product area (see Section 1.02.4). 

The need for simple descriptions of complicated organic ligands has led to the evolution of some trivial nomenclature systems, such as those for crown ethers (e.g. 76) 72AG(E)16) and cryptands 73MI10200), which have become quite elaborate 8OMII0200). These systems are intended primarily to indicate topology, and the positions of potential donor atoms, and are not particularly appropriate for general use. 

Chemical Abstracts preferred name, which aeema to us to embody the disadvantages of both systematic and trivial nomenclature. 

The Chemical Abstracts nomenclature will be adopted, but when common trivial names are available, these will also be employed, e.g., 4-pyrone along with 4if-pyran-4-one. Unlike Chemical Abstracts, thio will be used to designate a thione and thia will imply a sulfur heteroatom. 

The nomenclature used to describe the fused benzene-pyrrole-pyridine system of the compounds under discussion has been repeatedly modified, and the compounds have been numbered in an astonishing variety of ways since Perkin and Robinson introduced the name carboline for the ring system, which was encountered for the first time in the harmala alkaloids. In the earliest version of carboline nomenclature, the parent compound of the series, whose trivial name was norharman, was referred to as 4-carboline and numbered as in 1. Harmine (2) then became ll-methoxy-3-methyl-4-carboline. 

Chemical Abstracts), and a-carboline is sold commercially under the name 1-azacarbazole. The trivial norharman nomenclature, in conjunction with numbering as in 1 or as in 6, is still to be found in recent papers. Other systems of numbering, as well as some incorrect systems of nomenclature, are to be found and add to the confusion. 

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