Nomenclature bases, 668

Implicit ia the base names are the absolute configurations at carbons 8 and 12 and the iadicated numbering systems. Derivatives of these parent stmctures are named according to terpene and steroid nomenclature rules (see Steroids Terpenoids). The lengthy and awkward nature of the chemical abstract systematic nomenclature (12) for these compounds has resulted ia the development (13) and use of simplified nomenclature based on common names. 

In addition to the nomenclature based on ISO and ASTM recommendations several other abbreviations are widely used. Those most likely to be encountered are shown in Table 4. 

In all types of nomenclature based on triazine the numbering of the substituents is shifted by one as compared with the nomenclature of 6-aza analogs of pyrimidines. 

Ten specific mammalian calcium channel subtypes have been identified based on the sequence of their membrane pore-forming oq subunit. As illustrated in Table 1, calcium channels may be individually identified by their oq subunit, or more commonly using a systematic nomenclature based on a gene subfamily (Cavl-Cav3) and the order of discovery of the oq subunit (e.g., Cavl.l-Cav 1.4) [7]. 

Four isoforms of PLC ((3, y, 8 and e Fig. 20-3) have been identified in the brain, with the nomenclature based upon the chronology of their discovery. The a isoform was subsequently identified as a proteolytic fragment of PLC8 (for reviews, see [10,11]). Because the lower eukaryotes such as yeast and slime molds possess only the 8 isoform, it has been suggested that the other isoforms evolved... 

Quite often, we find nonsystematic nomenclature used in the literature dealing with organophosphorus compounds. This results in unnecessary confusion, as systematic nomenclature is easy to use and understand. Nomenclature based on the oxidation state of the phosphorus center eliminates the confusion and helps to promote understanding of the chemistry as well as to facilitate communication. Table 1.1 shows structures for tricoordinate and tetracoordinate phosphorus compounds related to oxyacids with their English general names. Also noted are the names for simple esters of the parent acids. They are organized based on oxidation state and the number of bonds of the carbon-phosphorus type. 

Table 3.2 Effect size calculation and corresponding nomenclature based on two cases...

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. 

Nebert, D.W. and Nelson, D.R. (1991) P450 gene nomenclature based on evolution. Methods in Enzymology, 206, 3—11. 

The cytochrome P450 system is the principal enzyme system for the metabolism of lipophilic xenobiotics. It is a heme-containing, membrane-bound, multi-enzyme system which is present in many tissues in vivo but is present at the highest level in liver. A coenzyme, cytochrome P450 NADPH oxidoreductase (OR), is essential for P450 catalytic function and cytochrome bs may stimulate catalytic activities of some enzymes. In human liver, it is estimated that there are 15-20 different xenobiotic-metabolizing cytochrome P450 forms. A standard nomenclature, based on relatedness of the amino acid sequences, has been developed (Nelson et al., 1993). The most recent... 

At present a less complicated nomenclature, based on the average number of (ON02)-groups attached to one anhydroglucose ring, is accepted ... 

Scheme 9 Topological arrangements possible for a linear Ns polyamine in an octahedral complex. The

Nomenclature based upon the process of formation of a particular adsorbate is to be discouraged. Thus, H may be dissociatively adsorbed hydrogen but the same species is formed in dissociative adsorption of... 

The mixture was next quenched with water and the resulting precipitated oil taken up in pentane, dried with sodium sulfate, and distilled under vacuum. The product was collected at 100° to 110°C at 0.001 mm/Hg, nD24-5 1.50 60. The infrared and ultraviolet spectrum corresponded to 10,ll-didehydro-9-ethoxy-9,12-dihydroretinol acetate, using carotenoid nomenclature based on the parent compound retinol. 

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. 

In order to circumvent this difficulty, the simplest way is to resort to nomenclature based on pentalene and name structure 10 1,6,6a SIV-trithiapentalene. This name brings out the abnormal valency of the sulfur atom numbered 6a (6aS1V) and permits us to apply the rule stating that such fusion names are related to the structure containing the greatest number of noncumulative double bonds. 

Named incorrectly as a 12-aza- -carboline derivative in Ghem. Abstr. 64, 19584 (1966). According to Ghem. Abstr., numbered as a carboline derivative it should be 7-aza-a-carboline. Since Ghem. Abstr. does not index carbolines, but does carbazoles, 1,7-diazacarbazole would be a more appropriate aza name. The correct nomenclature based on the Ring Index system would be 4,8-dimethyl-9-phenyl-9H-pyrrolo[2,3-6 5,4-c ]dipyridine. 

Since the chemistry of organic polysulfanes is closely related to their oxidized derivatives, Table 2 presents the well-characterized species with up to three sulfur atoms in the chain. The systematic nomenclature based on the lUPAC recommended name sulfanes is also given in Table 2. In addition, conventional names for some of these compounds are shown in brackets. 

This nomenclature-based CAS policy has now been replaced by a structure-based policy for selecting the preferred tautomer, giving a closer relationship with physical reality. 

The nomenclature reform of the French chemists was of fundamental importance, replacing the old body-spirit terminology with new terms, based on oxygen. The calx was now termed the oxide, and the spirit of vitriol became sulfuric acid. The assumption that oxygen was the acid generator, as its name implied, was flawed, but the systematic nomenclature based on the increase of acidity with increase of oxygen content lived on, e.g. the acidic component of the sulfides, sulfites, and sulfates. The definition of a chemical element as the latest term whereat chemical analysis has arrived ... 

Since this is in part an historical sketch, mention is made here of the interesting nomenclature suggestions of E. C. Franklin (10) for his liquid-ammonia work. We are accustomed to a so-called water world as far as chemical nomenclature and almost everything else are concerned. Franklin built up a corresponding nomenclature based on a liquid-ammonia world. 

Chapter VI deals with the mainly juridical matter of Nomenclature, The aim ie to have relative stability of scientific namesi One accepted taxonomic classification leads to only one correct name per accepted taxon. The internationally accepted principles are priority and the type-method, and in this chapter it is explained how to apply the 75 articles of the International Code of Botanical Nomenclature, based on these principles. 

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