Chemical structures file conversion

The different internal and external file formats make it necessary to have programs which convert one format into another. One of the first conversion programs for chemical structure information was Babel (around 1992). It supports almost 50 data formats for input and output of chemical structure information [61]. CLIFF is another file format converter based on the CACTVS technology and which supports nearly the same number of file formats [29]. In contrast to Babel, the program is more comprehensive it is able to convert chemical reaction information, and can calculate missing atom coordinates [29]. 

The opening window of Chem3D consists of the workspace (display window where 3D structures are displayed with rotation bar, slider knob, and action buttons), the menu bar (File, Edit, View, Tools, Object, Analyze, MM2, Gaussian, MOPAC, and Window menus), tool pallette (action icons for the cursor), and replacement text box (element, label, or structure name typed in this box is converted to chemical structure). Structure hie in. mol,. pdb, or. sml can be opened and saved from the File menu. Note PDB hies saved from Chem3D do not contain residue IDs.) The accompanying program, ChemDraw, draws 2D structures (.cdx) that are converted into 3D models (.c3d) by Chem3D. The molecular sketches from ISIS Draw (. skc) have to be converted to. cdx with ChemDraw for the 3D conversion. 

Drawing 2D chemical structures. ChemWhere for searching for MPG structures in word processing documents. Datalyst II for management of databases of chemical structure in dBASE-compatible files. ConSystant for reformatting data files between software applications. Chemeleon from Exographics for data file conversions. PCs. 

Substantial attention and progress has been made in the development of procedures to effect conversion between chemical substance representations. Zamora and Davis [26] describe an algorithm to convert a coordinate representation of a chemical substance (derived from input by a chemical typewriter) to a connection table. An approach for interactive input of a structure diagram and conversion of this representation to a connection table suitable for substructure searching is discussed by Feldmann [27]. The conversion of systematic nomenclature to connection tables offers a powerful editing tool as well as a potential mechanism for conversion of name files to connection tables this type of conversion is described by Vander Stouw [28]. 

Beginning with volume 121 (1994) of CAS Chemical Abstracts, structural representation and machine registration was begim for polymers previously handled only as text terms in the CA File. Backfile conversion is not planned. 

The CAS Registry System contains not only the Registry File for structural data, but also the Nomenclature File, containing CA index names and synonyms, which may be other systematic names, common names, trade names, etc. (see Nomenclature Searching and Nomenclature Automatic Generation and Conversion) Currency, there are over 24 million chemical names in the Registry System. 

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