However, when large numbers of struc tures must be handled, switching back and forth between the editor and spreadsheet can become tedious. Fortunately, if an OLE 1.0-enabled drawing package such as ISIS/Draw is available, the chemical structure editor can be activated directly from the spreadsheet by double-clicking a cell. In addition to manipulating single structures, it is also possible to import/ export complete chemical tables in the SD or SMD file format. The evaluated package was clearly de veloped for Excel 4.0. To use it with Excel 5.0, adjustments are required as described in the accompanying help files. One of the major drawbacks here is that the Excel 5.0 workbook format is not fully sup ported under Accord for Excel; although multiple spreadsheets can be added to the workbook, only the Accord for Excel spreadsheet is stored during the save op eration. Documentation The software package comes with an ex tensive manual describing all the func tions in detail. In general, the descrip tions are clear and accompanied by illus trative examples that are also available in the form of Accord for Excel data files. A shorter description of all functions is also provided through online help. For more advanced functions, such as looking up substituent property values, as well as the application of the functions in Excel mac ros, the user needs to have a good under standing of the basics of Excel functions and macro language. Using the software After the chemical structures have been entered into the spreadsheet, either through importing individual structures or a complete table, a variety of activities is possible. Most functions can be accessed
through either a pull-down menu or a but ton on a separate toolbar, and some spe cialized functions are accessed through the Excel function wizard. A number of simple functions are provided, including calculation of molecular weight, derivation of molecular formula, calculation of the percentage elemental composition, and display of the corresponding SMILES string. Copying, deleting, or moving struc tures is easily accomplished through the normal spreadsheet procedures. The real power of the package, how ever, comes into play in analyzing tables of chemical data. Chemical tables can be searched for structures containing a speci fied substructure, either as an exact match or by ranking in terms of similarity, and can also be sorted on the basis of de rived properties. After replacing substituents in a structure by either R or X desig nations to define a generic structure, it is possible to perform a so-called R-group analysis: Accord for Excel expands the ta ble to include additional columns listing the R-groups that have been identified in the examined structures. This in turn en ables retrieval of specific properties of these substituents such as log Ρ values or electronic substituent coefficients, pro vided they are contained in a substitu ent library. Accord for Excel comes with a small library of its own, but for specific ap plications or collections of compounds, the user can define a dedicated library. In our application, the R-group analy sis of the selected group of compounds was followed by sorting according to mo lecular weight of the substituents, which provided an easy screen for duplicate structures. These activities were easily ac complished, and resulted in organized ta bles of structures and substituents. We were then able to implement a specific li brary for the examined set of compounds and perform automatic retrieval of the log
Ρ contributions of the substituents con tained in this library. The instructions in the manual for these more advanced activ ities were not straightforward, however, and required some improvisation. The fi nal step consisted of the correlation of the property values with the retention times observed for the various compounds, which resulted in a model that could be used to predict the retention of other deriv atives of the generic structure. Reviewed byJoostStrasters, Nycomed R&D
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[email protected]; internet http://www.softshelt.com Version 1.0; $599, $399 government/ academic, $99 student
Entropy is a database manager used to store, search, and organize ChemWindow and ChemIntosh documents, structures, and other chemical information. Unlike traditional databases that store informa tion in tables, Entropy stores data by the page; the database window shows thumb nails of the data pages, but data can be edited, forms built, or query structures drawn only in ChemWindow or Chem lntosh. Common uses include archiving structure drawings, tracing samples and test results, storing routinely used forms, or managing an inventory of chemicals. Entropy requires either a 386-based PC with 4 MB RAM running Windows and ChemWindow 3.1.3 or a Macintosh with 4 MB RAM running System 7 or later and Chemlntosh 3.4.3. Entropy Lite, a re duced version that does not support forms or views and cannot do structure searches, is also available.
Analytical Chemistry, December 1, 1995 717 A
