Page 119 - Chiral Separation Techniques

96 4 CHIRBASE: Database Current Status and Derived Research Applications using …

The need for an overall and combined chemical structure and data search system
became clear to us some time ago, and resulted in the decision to build CHIRBASE,
a molecular-oriented factual database. The concept utilized in this database approach
is related to the importance of molecular interactions in chiral recognition mecha-
nisms. Solely a chemical information system permits the recognition of the molecu-
lar key fingerprints given by the new compound among thousands of fingerprints of
known compounds available in a database.
The first system designed to perform these basics was developed in 1989 [2]. In
early 1990, a first version of 5000 entries was made available to the scientific com-
munity on an IBM PC DOS-based program: ChemBase. Now, some 10 years later,
the database has increased to several tens of thousands of entries, and the entire sys-
tem can be searched with the powerful ISIS software [3] as rapidly as it was searched
on the old computer systems.
Since the original version was released, there have been significant changes [4] and
improvements following the advent of new generations of computers and chemical
substructure systems [5], but the main goal of the project has not changed: to gather
together comprehensive structural, experimental and bibliographic information on suc-
cessful or unsuccessful chiral separations which have been obtained on CSPs by liq-
uid chromatography, and with an emphasis on molecular structures searches.
Besides the rapidly growing accumulation of data, the need to systematize and
analyze the data becomes correspondingly ever more demanding. Hence today, the
challenge resides not only in the management of this huge quantity of information,
but also in its investigation in order to reveal the knowledge implicit within the data.
It must be emphasized here that CHIRBASE data can be directly exported from ISIS
under various formats; consequently, a number of different computational methods
and tools to handle and analyze these data can be readily employed.
In this chapter, we will discuss the present status of CHIRBASE and describe the var-
ious ways in which two (2D) or three-dimensional (3D) chemical structure queries can
be built and submitted to the searching system. In particular, the ability of this infor-
mation system to locate and display neighboring compounds in which specified molec-
ular fragments or partial structures are attached is one of the most important features
because this is precisely the type of query that chemists are inclined to express and
interpret the answers. Another aspect of the project has been concerned with the inter-
disciplinary use of CHIRBASE. We have attempted to produce a series of interactive
tools that are designed to help the specialists or novices from different fields who have
no particular expertise in chiral chromatography or in searching a chemical database.
Finally – and previously defined as a long-term goal of our development effort –
data collection has reached the point where meaningful data mining studies are
beginning to emerge. The extraction of implicit, previously unknown, and poten-
tially useful patterns from data is facilitated by the link between 2D or 3D database
searching, automated molecular property calculation, data analysis and visualization
tools (Fig. 4-1). These developments will certainly play an important role in our
objective to build an information system that provides not only a data collection but
also some knowledge about the processes of the chiral separation, and also help to
identify the research that is needed to fill the gaps in our knowledge.