Stereochemical notation

Our major objectives m this chapter are to develop a feeling for molecules as three dimensional objects and to become familiar with stereochemical principles terms and notation A full understanding of organic and biological chemistry requires an awareness of the spatial requirements for interactions between molecules this chapter provides the basis for that understanding... 

We mentioned in Section 7 6 that the d l system of stereochemical notation while outdated for most purposes is still widely used for carbohydrates and amino acids Likewise Fischer projections find their major application m these same two families of compounds... 

A Macromolecular Division of lUPAC was created in 1967, and it created a permanent Commission on Macromolecular Nomenclature, parallel to the other nomenclature commissions. The Commission over the years has issued recommendations on basic definitions, stereochemical definitions and notations, stmcture-based nomenclature for regular single-strand organic polymers and regular single-strand and quasisingle-strand inorganic and coordination polymers, source-based nomenclature for copolymers, and abbreviations for polymers. AH of these are coUected in a compendium referred to as the lUPAC Purple Book (99). 

Glycerolipids are derivatives of glycerol and fatty acids. Most brain glycerolipids are derivatives of phos-phatidic acid (PtdOH), which is diacylated sn-glycerol-3-phosphate. The notation sn refers to stereochemical... 

Sloan, T. E., Stereochemical Nomenclature and Notation in Inorganic Chemistry, 12, 1. 

In order to understand this concept, we need to learn some basic stereochemical principles and notations (optical activity, chirality, retention, inversion, racemisation, etc.). 

In the third model (finite chain with different terminal groups) no reflection symmetry element exists in the Fischer projection. The individual macromolecules are, therefore, chiral and all the tertiary atoms are asymmetric and different. The stereochemical notation for a single chain, depending on the priority order of the end groups, can be R, R2, R. . . R -2, R -i, Rn or R, R2, R3... 

Basie definitions of terms relating to polymerization reactions [1,2] and stereochemical definitions and notations relating to polymers [3] have been published, but no reference was made explieitly to reaetions involving the asymmetric synthesis of polymers. It is the aim of the present doeument to recommend classification and definitions relating to asymmetrie polymerizations that may produce optically active polymers. 

Stereochemical definitions and notations relating to polymers (Provisional), Pure Appl. Chem. 51, 1101-1121 (1979). Superseded by Ref 14. 

Most of the stereochemical arrangements found in these complexes are based oil the octahedron or on the tetrahedron, and may be derived from these configurations by a suitable distortion. Both basic systems have cubic symmetry and d-orbital energies are split into a triplet and a doublet. The group-theoretical notation will be used for their description. ... 

Figure 2.11 Some plausible confoimations of (2/f, 4Y )-l-hydroxy-2,4-dimethylhex-5-ene. How many different torsional isomers might one need to examine, and how would you go about generating them [Note that the notation 2/f, 45 implies that the relative stereochemical configuration at the 2 and 4 centers is R,S - by convention, when the absolute configuration is not known the first center is always assigned to be R. However, the absolute conformations that are drawn here are S,R so as to preserve correspondence with the published illustrations of Stahl and coworkers. Since NMR in an achiral solvent does not distinguish between enantiomers, one can work with either absolute configuration in this instance.]...

A general method of stereochemical notation based on the ligand priority sequence rule of Cahn, Ingold, and Prelog (CIP),8,9 developed at Chemical Abstracts Service,0 1 has been in use in Chemical Abstracts Chemical Substance Indexes for mononuclear coordination compounds since 1972. 

The structures in Figures 2-6 illustrate the utility of a ligand index-based stereochemical notation for coordination compounds. 

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