Nomenclature and structures

Structure and Nomenclature Search System. This system links the collection of chemical databases found in the Chemical Information System (CIS), one of the first interactive systems for stmcture and substmcture searching. References from the separate files can be retrieved by SANSS using CAS Registry Numbers, and the database of stmctures may be searched for stmctures or substmctures. An adaptation of the SANSS software for substmcture searching has been incorporated in the Dmg Information System of the National Cancer Institute for its own use (54). 

The structures and nomenclature for the common pine resin acids based on the abietane skeleton (abietic-type acids) are given in Fig. 8. The abietic, neoabietic, palustric and levopimaric acids differ only in tbe location of tbeir two double bonds. All double bonds are endocyclic, except in the neoabietic acid in which one is exocyclic. 

Figure 16-5. Chemical structure and nomenclature used for the oligol/runr-phenylcne vinylcne)s.

TABLE I. Abbreviations, Structures and Nomenclature of CMP and CMPO Extractants Employed in this Work... 

Figure 5.12 Structures and nomenclature of the ions formed in the mass spectral fragmentation of peptides which involve scission of the polypeptide backbone. From Chapman, J. R. (Ed.), Protein and Peptide Analysis by Mass Spectrometry, Methods in Molecular Biology, Vol. 61, 1996. Reproduced by permission of Humana Press, Inc.

SANSS. 1990. Structure and Nomenclature Search System. Chemical Information System (CIS)... 

From these stractural features it is interesting to note that each molecule of chlorophylls a and b consists of a hydrophilic part (tetrapyrrole macrocycle) and a hydrophobic portion (long terpenoid chain of phytol esterifying the acid group at C-17). Figure 2.1.2 shows the structures and nomenclature of chlorophylls a and b and their major breakdown derivatives. 

Basic Structures and Nomenclature of Simple and Complex Lipids.300... 

BASIC STRUCTURES AND NOMENCLATURE OF SIMPLE AND COMPLEX LIPIDS... 

ChemIDplus. Published by the U.S. National Library of Medicine, ChemIDplus [62] is a web-based search system, http //chem.sis.nlm.nih.gov/ chemidplus/, that provides free access to structure and nomenclature authority files used for the identification of chemical substances cited in National Library of Medicine (NLM) databases. ChemIDplus also provides structure searching and direct links to biomedical resources at NLM and on the Internet. The database contains over 349,000 chemical records, over 56,000 of which include chemical structures, and is searchable by name, synonym, CAS registry number, molecular formula, classification code, locator code, and structure. 

Weedon, B. C. L. and G. P. Moss (1995). Structure and nomenclature. Carotenoids, Isolation and Analysis. G. Britton, S. Liaaen-Jensen and H. Pfander, eds. Basel, Switzerland Birkauser Verlag, pp. 1A. 

Any further details concerning structure and nomenclature may be found within the body of this review, otherwise the reader is again directed to previous works <1984CHEC(5)733, 1996CHEC-II(4)127>. 

Nitrogenous base plus sugar moiety are called nucleosides. Ribonucleic acids (RNA) resemble DNA in that nucleoside monophosphates are joined through phosphodiester bonds. RNAs differ in that the sugars are p-D-ribose units and the pyrimidine uracil is found in place of thymine. Molecular structures and nomenclature for nitrogenous bases, nucleosides, and nucleotides are delineated in Table 2.2. 

An introduction to crystal structures and nomenclature is given in the Supplementary Material Section SI. 

Structures and nomenclature for the most important five-membered monocycles with one or more heteroatoms are depicted in Scheme 1. The aromaticity scale in five-membered heterocycles has been long debated.97-101 The decreasing order of aromaticity based on various criteria is (DRE values in kcal/ mol) benzene (22.6) > thiophene (6.5) > selenophene > pyrrole (5.3) > tellurophene > fur an (4.3). Pyrrole and furan have comparable ring strains (Scheme 38). The aromaticity of furan is still controversial 100 the NMR shielding by ring current estimated it at about 60% of the aromaticity of benzene, and other methods reviewed earlier102 estimated it at less than 20%. 

FIGURE 2.11 Structures and nomenclature of compounds that serve as auxiliary nucleophiles. Generation of activated esters. Substituted hydroxamic acids are sometimes added to carbodi-imides or other reactions to improve the efficiency of couplings. The additive suppresses side reactions by converting activated species into activated esters (see Section 2.10) before they have time to undergo secondary reactions, p(Me2SO) HOBt 9.30, HOAt 8.70. 

Ribbe P. H. (1983a). The chemistry, structure and nomenclature of feldspars. In Reviews in Mineralogy, vol. 2 (2d ed.), P. H. Ribbe (series ed.), Mineralogical Society of America. 

Table 6. Structures and nomenclature of proferrioxamines (pFO) (adapted from 110)Y...

Seeing the Structure and Nomenclature of Carboxiflic Acids and OeriOati(/es... 

In Chapter 9 you see the basic structure of each of the carboxylic acids and Ccirboxylic acid derivatives. In this chapter we focus on the carboxylic acids and related compounds, such as esters, acyl chlorides, and acid anhydrides, and we also include some information on amides (see Chapter 13 for an additional examination of cimides). Before you can get into synthesis and reactions, though, you need to understand the structure and nomenclature of these compounds. 

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