This paper describes classification and prediction for pharmacologically active classes of drugs under the presence of noise chemical compounds. Dopamine D1 receptor agonists (63 compounds), antagonists (169 compounds) and other drugs (696 compounds) were used for the work. Each drug molecule was characterized with Topological Fragment Spectra (TFS) reported by the authors. TFS-based artificial neural network (TFS/ANN) and support vector machine (TFS/SVM) were employed and evaluated for their classification and prediction abilities. It was concluded that the TFS/SVM works better than TFS/ANN in both the training and the prediction.
Relationships between the HOMO energy, the ν(C=O) stretching band, basicity(pKa), and σ(p) in phosphorus ylides have been studied. A linear relationship between the HOMO energies obtained by the AM1, HF/3-21G, and HF/6-31G methods and pKa was found. The same linear relationship was found between the HOMO energies obtained by these methods and σ(p)(indicated p-position). Thus, the HOMO energy can be adopted instead of pKa and σ(p) for choosing the ylide as the donor in organic reactions. In addition, a linear relationship between the ν (C=O) stretching bands obtained by these methods and the parameters described above was found. Hence, as for the electron donation of the ylide, it is noted that the HOMO energy can be used instead of pKa as a new method for showing the basicity of ylides. Furthermore, the ν(C=O) stretching bands obtained by these methods can be estimated by the HOMO energy obtained by the same methods.
The XyMTeX2PS system for typesetting chemical documents having structural formulas has been developed to cover both traditional printing and Internet communication. The system is capable of providing chemical documents as PostScript files of high quality. The PostScript files can be converted into PDF files, which serves as a key to cover both of the fields, where more elaborate stereochemical expressions such as wedged bonds are available.
The XyM2Mol system, which consists of the XyM2Mol application and the XyM2Mol applet, is developed to convert XyM-notation codes into connection tables. Thereby, the structural data by XyM Notation become applicable to a wide variety of chemical applications through such connection tables.