Representation of Chemical Compounds

Representation of Chemical Compounds 21 Structure diagram Condensed formula... 

Representation of Chemical Compounds 29 Table 2-3. Basic SLN syntax without description of attributes and macro atoms. 

The DARC notation (see, for example, ref. 228) is a system of computer representation of chemical compounds rather than a system for the input of molecules into the computer. It will thus not be discussed here. 

IUPAC-like expressions, true IUPAC nomenclature names, and InChl and SMILES representations of chemical compounds are well suited for detection by machine learning approaches. Conditional random fields (CRFs)41 and support vector machines have been used for the detection of IUPAC expressions in scientific literature 42 Other approaches are based on rules sets43 44 or combinations of machine learning with rule-based approaches 45 All these approaches have in common that they face one significant problem the name-to-structure problem. 

There are no formal rules for the representation of chemical compounds, although a few special cases such as steroids and carbohydrates have evolved a preferred style. This chapter will outline the revised drawing conventions used in the Combined Chemical Dictionary (CCD) (see Section 1.2.1), which other chemists may wish to follow. (CCD diagrams have, however, been added continuously over a period of nearly thirty years. This description is of best current practice.) These rules, when followed, will result in a drawing style that is consistent and unambiguous to the reader. 

In contrast to Dalton s system, Berzelius —which predated Dalton s and is the basis for the representation of chemical compounds by their molecular formulas that... 

An algorithm for extracting useM information from the topological and geometrical representation of chemical compounds was developed and integrated to calculate molecular descriptor family (MDF) members [55]. The activity is predicted based on a learning set, a preciously obtained MDF SAR model and a molecule submitted as HIN file by the user. 

In this book, we shall describe algorithms for solving these problems. The techniques are based on the representation of chemical compounds as molecular graphs, i.e. they are mainly applied to constitutional isomers. 

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