To search for available starting materials, similarity searches,
substructure searches, and some classical retrieval methods such as
full structure search, name search, empirical formula search, etc. have
been integrated into the system. All searches can be applied to a number
of catalogs of available fine chemicals (e.g. Fluka). In addition, compound
libraries such as in-house catalogs can easily be integrated.
searches are essential methods in WODCA to be used to generate a relationship
between the synthesis target or precursors and available starting materials.
Similarity searches in WODCA are performed on the basis of similarity criteria
that are either based on the presence of substructures or on generalized
contains a rule for the transformation of the query structure (target,
precursor). The transformed query is then compared with all transformed
molecules in the database (the transformed molecules in the database had
been computed and stored during the implementation of the catalog). If both
the transformed query and the transformed catalog compound are identical,
then the database structure is suggested as suitable starting material to
the user. The principle of similarity searches is illustrated by the criterion
‘maximum oxidation state’ in the following figure:
for identity of chemical structures is performed on the basis of a hashcode
algorithm . Hashcodes are unique integer numbers which can be calculated
for each chemical structure within the WODCA system.
W. D.; Gasteiger, J. "Hashcodes for the identification and classification
of molecular structure elements" J. Comput. Chem. 1994,