Chiral substructure searching

Using simple rules, a structure is represented by a string of characters unique to that structure. It can also be used to specify stereochemistry at double bonds and chiral centres. SMARTS is a further extension that allows substructure searching. 

In order to address the problem of performing substructure searches for chiral moieties, a method of designating both absolute and relative configuration in molecular structures was developed. Then a small chemical structure database containing 25 mono and disaccharides was created in order to test the concept. Results from tests show this method to be viable and expandable to other types of compounds. 

Different problems for substructure searching on chiral compounds arise in two-dimensional structure databases compared with three-dimensional databases. The two-dimensional case is the worse of the two, because two-dimensional databases... 

In order to achieve precise and accurate substructure searches for chiral moieties, at least two conditions must be met there should be a standard method of... 

Similarly, in creating a stereochemical designation for each chiral centre, every molecule in the database must first be oriented according to the same rules, and the same method of designating the attachments must be used for every chiral centre. In addition, the program must be able to access specific atomic information for every chiral substituent, allowing for more flexible substructure searching. 

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