Stereochemistry notational systems

Two-dimensional representations alternative to the molecular graph are the linear notation systems, for example, Wiswesser Line Notation system (WLN) [Smith and Baker, 1975], SMILES [Weininger, 1988, 1990, 2003 Weininger, Weininger et al., 1989 Convard, Dubost et al., 1994 Hinze and Welz, 1996], and SMARTS (SMART - Daylight Chemical Information Systems, 2004). CAST (CAnonical representation of STereochemistry) is a method that gives a linear notation that canonically represents stereochemistry around a specific site in a molecule [Satoh, Koshino et al, 2000, 2001, 2002],... 

Fischer projections and d-l notation have proved to be so helpful m representing carbohydrate stereochemistry that the chemical and biochemical literature is replete with their use To read that literature you need to be acquainted with these devices as well as the more modern Cahn-Ingold-Prelog R S system... 

Stereo-chemistry has played a large role in attempting to understand the visual process. While its role in the actual chromophores of vision appears to be negligible, the stereochemistry of other retinoids is widely discussed. However, many different systems of notation have been used over the years. Goodwin provides a broad review of this terminology39. 

To examine the stereochemistry of the SE process, we use the conformational notation. The intermediate 55 is formed by attack of an electrophile on the 77-system. Not all of the possible conformations of... 

The terminology and notation that have been used to describe coordination compounds have been derived with one notable exception from the terms and symbols developed to describe the stereochemistry of carbon compounds. The terms ois, trans endo, exo dextro, d, D, (+) and leva, l, L (-) all have been used to describe the stereochemistry of coordination compounds in a close analogy with organic compounds (see Figure 1). As the descriptions of the chemistry and structures of coordination systems have become more varied and complex, the meanings of these terms have become less precise, as in the example of a ois or trans tricarbonyl octahedral compound (see Figure 2). The terms fao and mer were coined to indicate the facial and meridional disposition of substituted octahedral structures. 

Notation to describe stereochemistry, chemical formulae or chemical structure are available in some online systems, in some instances these data can be exported directly into software packages for graphical displays and further manipulation. 

The usual chemical structure representation (CSR) of a compound in chemical information systems is the connection table, adjacency matrix, linear notation, or structural lists which describe the molecular structure. The CSR contains all the information required to characterize fully the chemical structure of a compound, i.e., the chemical nature of atoms, bonding information, stereochemistry, and geometry (see Structure Representation). 

---