Numbering and Nomenclature

The nomenclature and numbering of formulas for berberine and its derivatives is based on the system adopted by Buck, Perkin and Stevens for the parent substance of the series, protoberberine (XXIV). Awe has suggested that tetrahydroproioberberine should be called berbine and used as the basis of a system of names for these alkaloids. 

The pyridopyrimidines discussed in this review are derived by the ortho fusion of the pyridine and pyrimidine rings through ring carbon atoms. There are four such compounds for which the nomenclature and numbering of Chemical Abstracts (1-4) will be used. Alternative names used in the literature are 1,3,8-triazanaphthalene (1), 1,3,5-tri-azanaphthalene (2), 1,3,7-triazanaphthalene or copazoline (3), and 1,3,6-triazanaphthalene (4). There has been no previous review of the... 

The nomenclature and numbering system adopted in this article is the one currently widely used in the literature and corresponds closely to the one suggested by Shaw (13,17). Only the chemistry of chlorocyclo-phosphazenes is dealt with in this review. The structural and bonding aspects are not considered here. 

The nomenclature and numbering used above are recommended by lUPAC (1998PAC143), and they can be further applied to the other cyclic systems with one or more heteroatoms on the heteropine ring using the order of preference rules. Thus, fusion of pyrrole (54), furan (71) or thiophene (78) with azepine (43), oxepine (67) or thiepine (78) results in chemical names in which the parent heterocycle has the lowest preference number and is cited last in the name (preference numbers from Appendix II (1998PAC143) are in brackets). Explanation of the fusion descriptors can be found in the lUPAC recommendations (1998PAC143) and were exemplified in CHEC-I (1984CHEC-1(1)7). 

Nomenclature is not a static subject. It changes as new kinds of compound are synthesised and new procedures and devices have to be invented. Fullerenes are a case in point, and their detailed nomenclature and numbering are currently (1997) under discussion. Even established procedures are continuously being reviewed and revised, but the principles established in this survey are likely to remain recommended for the foreseeable future. 

In this review the nomenclature and numbering originally given by Newman 1( will be used. As an example the numbering of hexahelicene is given. In the example the quaternary carbon atoms are not numbered, but on addition of a group at these carbon atoms they are numbered as usual in polycondensed aromatic systems. For the x-ray analyses (and also i3C-NMR etc), the quarternary carbon atoms are numbered separately. 

The Pesticide Index (ref. 14) lists the following categories of pesticides acaricides, attractants, chemosterilants, defoliants, fungicides, herbicides, insecticides, molluscicides, nematicides, plant regulators, repellents, and rodenticides. Listings are in alphabetical order with structural and molecular formulae for single chemical entities. Other data include CAS nomenclature and number Wiswesser Line Notation LD-50 and test animal data when available physical appearance and safety information. Also provided are a CAS nomenclature index separate molecular (line) formulae of chemicals identified by their common names a separate section of Wiswesser line notations, also with common names an appendix of manufacturers, and an appendix of recent publications dealing with pesticide names. 

Nomenclature and numbering of atoms in molecules used for calculations in Tables 5 to 14... 

The Chemical Abstracts nomenclature and numbering system will be used throughout the discussion. 

If there is only one functional group, this takes precedence in nomenclature and numbering. 

Nomenclature and numbering according to Ehmann and Ballschmiter [235] and in order of elution. 

The nomenclature and numbering follow Chemical Abstracts. b System has not been synthesized. c Parent compound has not been synthesized. 

Ligands considered as neutral molecules are given a name according to the rules of Ref. 3, including the special nomenclature and numbering applied to fused polycyclic or unsaturated heterocyclic ligands (see Section P-25 of Ref. 3). 

I Its nomenclature and numbering of carbon atoms may be different from that used for the simple furantrione. 

A few typical examples of steroidal drugs together with their nomenclature and numbering are illustrated below ... 

The nomenclature and numbering adopted are those used in Chemical Abstracts. The parent, 1-benzo, and dibenzo[6/]systems are numbered as shown in compounds (I) to (4). The name for the saturated monocyclic sulfide (4) is thiepane, not hexahydrothiepine. Since the lUPAC recommendation for the nomenclature for monocyclic heterocycles in 1983 <83PAC409>, thiepine is optionally used for the unsaturated system however, thiepin is favored by Chemical Abstracts, throughout this chapter thiepine is used. 

Several authors, however, prefer non-CAS nomenclature and numbering. 

Fig.2. Ring nomenclature and numbering of the carbon atoms in the steroid molecule. The lUPAC-lUB Joint Commission on Biochemical Nomenclature recommended in 1989 ur. J. Biochem. 186 (1989) 429-458] that the numbers shown within the ellipses should replace the numbers shown in bold type the latter were assigned in the 1969 recommendations lEur. J.Biochem. 10 (1969) 1-19] and the amendments to them lEur. J.Biochem. 25(1972) 1-3] all other numbers are unchanged.

Fig. 1 Nomenclature and numbering for indenofluorene isomers. Italicized numbers denote numbering for methylene bridge orientation, non-italicized numbers denote atom...

CgHioOs 130.143 Care needed with nomenclature and numbering. Shown here numbered as pyrans. If named as carbohydrates, it is preferable to consider all stereoisomers as hex-l-enitols, in which case positions 2,3,4 become 5,4,3 respectively. Strict application of the lUPAC special rules for carbohydrates would mean that some of the stereoisomers would be named as hex-5-enitols not hex-l-enitols (e.g. 2,6-anhydro-l, 5-dideoxy-arafeino -hex-5-enitol is preferred over 1,5-anhydro-2,6-dideoxy-/> xo-hex-l-enitol), in which case 2,3,4- remain 2,3,4- but with the Me group not the O atom numbered 1. 

Last, but by no means least, our system of nomenclature and numbering can be applied not only to lignans and neolignans (i.e. Cg-Cs-dimers) but also to Cg-C3-oligomers without any change of concept. Several trimers (Fig. 7.3.8) and tetramers (Fig. 7.3.9) have already been isolated and it is easy to foresee that many more will be described in the future. 

Thus although based on biogenetic reasoning, supported at times by biomi-metic interconversions or even only by mechanistic speculations, we consider the nomenclature and numbering proposed in the present work to constitute the best classificatory criterion in the lignan-neolignan domain of secondary metabolites. 

---