Semisystematic name

Trivial name Systematic or semisystematic name Structure... 

Table 7.2. Trivial and semisystematic names of common food carotenoids (Rodriguez-Amaya...

The IUPAC nomenclature system recognizes that most of the common (commercial) polymers have source-based or semisystematic names that are well established by usage. IPUAC does not intend that such names be supplanted by the IUPAC names but anticipates that such names will be kept to a minimum. The IUPAC system is generally used for all except the common polymers. The IUPAC names for various of the common polymers are indicated below the more established source or semisystematic name in the following ... 

The classic (if not classical) metal sandwich species bis(cyclopentadienyl)iron has the formula [(CH)5]2Fe (CpaFe) and the semisystematic name ferrocene, and so the related magnesium-containing species [(CHfsJaMg (CpaMg) is often accompanied by the name magnesocene. We commence our discussion with this species. 

Trivial name Semisystematic name Type Vitamin A activity (%)a... 

Goodwin has provided a useful summary of the structural chemistry applicable to the retinoids of vision36. However, the book is not as comprehensive as needed to address all of the types of Vitamin A. He also refers to a separate essay on the structural notation he uses37. Taylor Ikawa have provided additional nomenclature, more semisystematic names and excellent information on laboratory evaluation techniques38. 

Semisystematic names. Examples of semisystematic parents are corynoxan and labdane. DNP makes widespread use of semisystematic names for terpenoids and steroids (where skeletons such as labdane have not been used in CAS nomenclature since 8C1). lUPAC gives tables of recognised semisystematic parent skeletons and directions for introducing new ones, but in view of the discovery of ever more structurally complex types of natural products, most authors have avoided this route. Semisystematic parents can be modified by operators such as nor-, abeo. 

Special cases. There are a few cases where trivial, nonsystematic or semisystematic names are still allowed. Some particular examples are shown. 

Persistence of trivial and semitrivial (or semisystematic) names—e.g., nitrotoluidine, aminocresol, etc.—which, though convenient, are not systematic and may be confusing, as, for example, the nitroanisidines, where o-nitro-p-anisidine is an ambiguous form. 

Because this combination of trivial common names and semisystematic names was found to be inadequate, the International Union of Biochemistry (lUB) appointed an Enzyme... 

We give what we trust is a generally intelligible semisystematic name and often accompany it with another name, prefaced by ON that has been used elsewhere, often by the original authors of the original calorimetric study and/or the thermochemical archive from where we obtained the cited enthalpy of formation. 

Semisystematic names proposed by the IXJPAC Committee for nomenclature could well be applied to Verairum alkaloids with the exception of veramine. The C-16 hydrogen in veramine is /S-oriented, whereas the side chaiit at C-17 is a-oriented hence tomatanine, which has a C-16 a- and a C-17 a-hydrogen, could not be taken for the fundamental skeleton. Some other Veratrum alkaloids (e.ff., veralkamine, veralinine) having the C-17 side chain a-oriented are entered among the C-17 )S-methyl-18-nor-epiminocholestanes. 

Glycosyl units Semisystematic name Generic name Abbreviation Molecular weight Aqueous solubility [g/lOOmL] Surface tension (mN/m) Specific rotation [ Id Half life of ring opening (h) Radius of gyration (A)... 

The traditional demarcation of the chemistry of natural products from, e.g., the rest of organic chemistry, physics, biosciences and, in particular, biotechnology, molecular biology, and research on active principles is no longer possible. Thus the entire field of the extensively widened topic of natural products chemistry is now often referred to as bioorganic chemistry . The nomenclature principles of natural products - use of semisystematic names - are discussed in Section F of lUPAC rules. The Compendium of lUBMB, Biochemical Nomenclature, London Portland Press 1992, and in the Chemical Abstracts Index Guide. 

Carotenes are hydrocarbons with the basic carbon skeleton of I. Acyclic carotenes have the end group ifi on both ends of the molecule, whereas cyclic carotenes have one or two cyclic end groups of the type shown in Fig. 1 (fi, e, K, double bonds with respect to the normal pattern of I. Examples of acyclic and cyclic carotenes are shown as II-VII. The common and semisystematic names of these compounds are given. 

In 1972 tentative rules for the nomenclature of carotenoids were adopted by the lUPAC Commission on the Nomenclature of Organic Chemistry and the lUPAC-IUB Commission on Biochemical Nomenclature. These were revised in 1975. The names given to carotenoids are based on the stem name carotenes, and the numbering of the carbon atoms is as shown in (I). In this chapter the appropriate semisystematic names are given, along with the common names for carotenoids. 

It has been suggested (212) that semisystematic names based on parent structural types be used whenever possible. The name of the parent structure is derived from the trivial name of the member first isolated. This name, when used for such derivations, besides indicating the carbon skeleton, implies, without further specification, the absolute configuration at all chiral centers of the parent. Carbon skeletons closely related to a parent structure are often named by using prefixes such as cyclo , nor , homo , seco , abeo etc. with the parent name, as indicators of modification. The prefix ent (short for enantio ) is used to indicate inversion at all chiral centers implied in the parent structure. 

Three naming systems are in use for steroids trivial names (cholesterol, cholestanol, etc.), semisystematic names (use of trivial name such as cholesterol as a parent), and truly systematic names with commonly accepted saturated hydrocarbons as parents. The most often encountered steroids are derivatives of the parent, 5a-cholestane (2 lacking the HO-group) where 5a refers to the presence of an a-H-atom on C-5. Thus, cholestanol (2) is systematically 5a-cholestan-3yff-ol and cholesterol is cholest-5-en-3yff-ol. Cholestanol could also be described semi-systematically as 5a-dihydrocholesterol. 

Trivial and Semisystematic Names for Some Carotenes and Xanthophylls... 

The names of the monomers are those common or semisystematic names that are encountered most often in the literature of polymer science. The order of citation of monomers in cqpotymer names is aibitraiy. 

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