Advanced Chemistry Development database

Advanced Chemistry Development Inc. has built a sizeable proton chemical shift database derived from published spectra (most commonly in CDCI3 solution). Their H NMR predictor programme accesses this database and allows the prediction of chemical shifts. Whilst this software takes account of geometry in calculating scalar couplings, in predicting chemical shifts it essentially treats the structure as planar. It would therefore seem doomed to failure. However, if closely related compounds, run at infinite dilution and in the same solvent, are present in the database, the conformation is implied and the results can be quite accurate. Of course, the results will not be reliable if sub-structures are not well represented within the database and the wide dispersion of errors (dependent on whether a compound is represented or not) can cause serious problems in structure confirmation (later). ACD are currently revising their strict adherence to HOSE codes for sub-structure identification and this will hopefully remove infrequent odd sub-structure selections made currently. 

In addition to the published literature, a chemical shift database is being developed by Advanced Chemistry Development (AC D/Labs) that can be used interactively by an investigator both to predict chemical shifts for a molecule being investigated and to search the database by a multitude of parameters, including structure, substructure, and alphanumeric text values. This database is accessible in the NNMR software package offered by ACD/Labs and presently contains data on more than 8800 compounds with over 20 700 chemical shifts. Examples of the use of the NNMR database will be presented later in this chapter. 

When applied to the MDDR and CMC databases, this filter classified almost 70% of molecules as drug-Uke, while in the Advanced Chemistry Development (ACD) database only 36% of molecules were found to be drug-Uke. The advantage of this filter is that it provides a detailed structural reason for classifying molecules as drugs or non-drugs. 

Fig. 19 Metabolic pathway of fluoxetine in humans, physicochemical descriptors, and toxicity model. Physicochemical properties are from (a) [66] (b) Physprop database www.syrres.com, (c) estimated with fragment method according to [11], (d) calculated using Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris...

The Advanced Chemistry Development (ACD) presents a toolset of PC and web-based software for NMR prediction, processing, and database management also for F (>11500 spectra), P NMR (> 18 500 spectra) and for MS, IR, UV-Vis and chromatographic databases. The operation of an actual NMR spectrometer can be simulated here, allowing to choose among different spectra modes (off-resonance, y-modulation, DEPT) just as the operating frequency, the solvent and the concentration of the solute. 

In certain situations, a computational chemistry approach may be useful. The procedure just described for estimating pKa from similar known compounds has been turned into an algorithm in the program ACD/pKa DB from Advanced Chemical Development (www.acdlabs.com). The program performs reasonably well (average accuracy of 0.2 pKa units for common organic compounds), and its database can be supplemented with pK l values of compounds studied in-house. 

This is a rapidly developing subject. There is an increasing number of on-line databases readily available to the organic chemist. It is likely that all organic chemists will require skills to conduct searches of such databases in future. Any advanced course in organic chemistry should therefore provide an introduction to on-line searching techniques in order to provide the basis for development later in the student s career. A detailed account of this field is beyond the scope of this appendix and would in any case date rapidly. The reader is referred to recent monographs for further information.4,7... 

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