Structure-based separation databases

The AGD/LogP algorithm [54, 55] is based on logP contributions of separate atoms, structural fragments and intramolecular interactions between different fragments. These contributions have been derived from an ACD/Labs internal database of over 18 400 structures for which one or more experimental log P values have been published. The log P increments are stored in the internal databases of logP contributions ... 

Structure-based separation databases integrated with other analytical and pharmaceutical information provides a basis for a significant increase of development efficiency. 

Structure-based tools such as applications databases and physicochemical prediction will not replace chromatographers, but rather allow them to use their knowledge of chromatography, relating it to the analyte functionality and making excellent choices of initial conditions that reap faster, better separations in less time. 

The functions of a model base management system (MBMS), a structure for which is illustrated in Figure 10, are quite analogous to those of a DBMS. The primary functions of a DBMS are separation of system users, in terms of independence of the apphcation, from the physical aspects of database structure and processing. In a similar way, a MBMS is intended to provide independence between the specific models that are used in a DSS and the apphcations that use them. The purpose of a MBMS is to transform data from the DBMS into information that is useful for decision making. An auxiliary purpose might also include representation of information as data such that it can later be recalled and used. 

A strict separation of these three types of databases is difficult hence most databases contain a mixture of data types. Therefore the classification given here is based on the predominating data type. For example, the major emphasis of a patent database is on hterature, whereas it also comprises numeric and structural data. Another type is the integrated database, which provides a supplement of additional information, especially bibhographic data. Thus, different database types are merged, a textual database and one or more factual databases. 

More than 100 CSPs are commercially available nowadays, which should make the separation of any pair of enantiomers feasible. However, the enantiorecognition mechanisms involved in the chiral recognition between the analytes and the CSPs are complex and therefore the selection of the appropriate CSPs, depending on the structure of the analyte, is a difficult task. A common approach to develop a new enantioseparation is the stepwise trial-and-error approach based on detailed consideration of the enantiorecognition mechanisms between the chiral selector and the analyte, or on the analyst s experience, or on the consultation of literature or databases. However, this approach is time-consuming and often unsuccessful owing to the fact that achieving enantioresolution is often purely empirical... 

Atkinson (1987) developed very reliable fragment additivity SARs for estimating kHO(air) from molecular structure using more than 400 compounds in the database (Chapter 14 describes procedures for using these SARs). SARs for HO are based on the premise that rate constants for each of the several different classes of reactions of HO with organic compounds — abstraction of H- atom (kH), addition to double, triple or aromatic bonds (kE), and reaction with S or N atoms (kA) — can be estimated separately and then summed to give the total molecular rate constant, kHO ... 

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