Databases Chemical -. Merck

OtherD t b ses. Available from different vendors (Table 8). For example, the researcher can obtain physical properties by usiag the Merck Index Online or the Dictionary of Organic Compounds available by Chapman and Hall Chemical Database. In DIALOG, numeric databases are collected under the name of CHEMPROP. 

The examples from SciFinder and the Merck Index are not intended to question the quality of these products, which we consider to be outstanding. They are invaluable resources to many chemists worldwide, and the error rate in these two databases is insignificant if one takes into account the enormous volume of indexed data. One of us has published a structure-activity paper on HIV-protease inhibitors [31] where a modified peptide was present in both the training set and the test set. Al Leo of Pomona College has recently [32] detected 100 chemical and name errors in the printed version of the sixth edition of Burger s Medicinal Chemistry [33], errors that will be corrected in the on-line edition [34]. One can never be too careful in verifying the available information, in particular if one is to invest a significant amount of resources in that area. 

Specialized properties that are not covered in these standard databases can be found in specialized books. The properties of food can be found in Physical Properties of Foods (Peleg and Bagley 1983). The properties of many petroleum products can be found in Petroleum Products Handbook (Guthrie 1960). The Merck Index (1996) lists chemicals, drugs, and biologicals. 

Chemical Databases ChemACX Database, ChemSAR Properties, The Merck Index, Chemical Databases... 

In-house chemical information management systems began to emerge at some of the larger chemical and pharmaceutical firms. These included CONTRAST and SOCRATES at Pfizer, SYNLIB at SmithKline, COUSIN at Upjohn, MSDRL/CSIS at Merck, and CROSSBOW at ICI (27). The Chemical Abstracts database was made available online in 1967 (28). In 1980 this became CAS ONLINE. A compre-... 

An identical approach was used by Branca et al. [16] at Merck and led to the identifcationofanovel inhibitor of poly(ADP-ribose) polymerase-1 (PARPl). The 2D descriptors were similar to the CATS all the two-point pharmacophores in each molecule were derived from all possible atom pairs and described in terms of atom types, number of Jt electrons, number of heavy atoms attached, and number of covalent bonds separating the two atoms along the shortest path. Known PARPl inhibitors were collected from patents, publications, and publicly available databases and used to train a support vector machine (SVM) classifier. A SVM constructs the plane that best separates active and inactive compounds in the multidimensional space defined by the molecular descriptors. The results of the SVM were used to classify the compounds in the Merck collection and those predicted to be active were screened. One compound was particularly potent and was chosen as the starting point for a structure-activity relationship (SAR) exploration of this chemical class. Docking studies on the PARPl crystal structure were used to guide the synthetic efforts. 

Many chemical databases are available, usually through your school The CRC Handbook of Chemistry and Physics is the standard reference for many types of data and is available in libraries. The Merck Index is a standard reference for the properties of many small organic compounds, especially ones of biological interest. WebEle-ments (http //www.webelements.com) is a good Web site for looking up the properties of the elements. 

Table 13.1. Lethal dose and relative classification of some substances (Source The Merck Chemical Products Database Chemdat and NTP, National Toxicology Program, USA)...

Technique 29, Section 29.11). You may need to search a computerized database to get the necessary information, or you may be able to find it in the Aldrich Catalog Handbook of Fine Chemicals, issued by the Aldrich Chemical Company. Current issues of this catalogue include listings of substances by CAS number. In your report, you should also report the relative percentage of the substance in the tablet extract. Finally, your instructor may also ask you to include the "quality" parameter from the "hit list." If possible, determine which components have antihistamine activity and which ones are present for another purpose. The Merck Index may provide this information. 

---