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Text editing properties In the case of chemical documents it is necessary to distinguish between two kinds of text: structural text (atomic symbols, functional groups, atom labels) and other text (captions, reaction conditions, annotations etc.). The structural text strings are connected to the atoms, the latter can be placed freely, usually into text boxes and can be edited independently. Of course, in these chemical applications only a minimal amount of text editing features can be found, like the basic manipulation of fonts, styles, sizes and colours. The technique is mostly that used in other Windows applications.  These programs are widely used all over the world. A problem of the previous ChemDraw versions, namely the support of the national character sets is now flawless, but in DrawIt and ChemSketch this should be fixed in the forthcoming version.
Templates and group abbreviations Apart from Chemistry 4-D Draw, the programs contain several ready template pages of different ring systems, amino acids, carbohydrates etc. and these can be pasted quickly into the document. Other templates, for example laboratory glassware, are also available. The programs allow the user to create custom templates. Of course, the technique of the creation and use of the templates are differing in the five programs from each other, maybe the solution and organization used by ChemSketch is the most advanced one.   ChemDraw, DrawIt and ChemSketch have another chemically intelligent method. A substituent or not very complicated side chain can be entered in text form, such as -CH2OCH2COOH, and the parser of the program interprets and expands it. The expression may contain parentheses too. The adding of new bonds to any atoms in the expression is allowed too (Figure 11. A). The expansion of a longer linear formula to the corresponding formula may lead to different arbitrary 2D conformations. The algorithm of ChemDraw seems to be the most advanced one (ISIS/Draw understands only a few basic groups: COOH, NO2). ChemDraw and DrawIt allow the use of stacked labels. It is difficult to decide which of the above methods is the better one for the addition of substituents: predefined structures or on-the-fly interpretation of linear formulas. Both of them have its own advantages and weak points. Chemistry 4-D provides its own solution. It possesses an intelligent chemical nomenclature module. Therefore it contains only a few built-in templates (the most important rings and substituents). In addition, every molecules can be saved as a fragment (like cephem in Figure 13.), and later it can by recalled by its name, even in substituted form:   Tips for ISIS/Draw users: there are a few issues regarding the entering of substituents or atoms from the keyboard, these are not covered by the program Help or are not correct.A predefined substituent or moiety (abbreviated structure) can be added to the selected atom by simply entering its name from the keyboard. You can choose whether to have the abbreviated structure appear in your sketch as text or as the full structure. The default can be set from the Preferences | General tab. However, you can control it simply from the keyboard too: Click on an empty place or select an atom, then enter from the keyboard a) *ph, b) ph. The leading asterisk reverses the default setting in Preferences. So in one case the full phenyl group is added to the drawing, the abbreviation "Ph" otherwise. Starting with the + symbol, it sprouts an additional single bond too: thus, +*ph or +ph adds a benzyl group. Similarly, OH adds a hydroxyl, +OH (or +*OH) a CH2OH group. For rings use *ring7, +*ring7, for amino acids *ALA or +*ALA (in capitals!). More tips...
Chemical intelligence, nomenclature As it was already mentioned, the programs ChemDraw, ChemSketch and DrawIt are capable of parsing the linearized forms of substituents and convert them to structures. ChemDraw Ultra, Chemistry 4-D Draw, DrawIt and ChemSketch are able to assign systematic names to structures according to IUPAC rules, and vice versa. ISIS/Draw‘s capacities can also be extended to naming by installing its AutoNom or the ACD/Name Freeware add-in. Therefore these are very convenient for generating chemical names.  These modules are very intelligent and are difficult to cheat, although not faultless, especially on slippery fields of nomenclature, such as carbohydrates. Some of their databases can be customised by adding trivial names. There are a few restrictions, anyway, for example multicomponent ionic structures will not be interpreted in DrawIt or Chemistry 4-D Draw while this is not a problem inside ChemSketch Name or ChemDraw. The presence of these usually extra features are depending on the purchased version or edition of the applications! ISIS/Draw needs Beilstein‘s AutoNom add-in; it failed in the case of several very simple compounds, such as diphenylmethane. The basic ChemSketch contains the structure-to-name feature only, the opposite is to be purchased separately or available through the online service ACD/I-Lab. ChemDraw Ultra also possesses an appropriate module (earlier based on Beilstein‘s Autonom 2.2, now a new proprietary one). In ChemDraw 9.0 a praiseworthy auto-update feature has been added that renames the structure as you modify it. However, only bicyclo condensed ring systems are assigned, higher ones not. Basic DrawIt contains only demo capabilities. If you need more, try the ACD/Name application, which wins in a canter even in the jungle of oligosaccharides. (Example) In addition, the latest versions of ChemDraw and ChemSketch are able to assign on-the-fly the stereochemistry to all asymmetric tetrahedral atoms and double bonds according to Cahn-Ingold-Prelog (CIP) priority rules:  Of the five programs only in Chemistry 4-D is possible to define and add full structures with trivial names to the nomenclature database, as mentioned above. The commercial version of ChemSketch includes an integrated dictionary of more than 100000 names which can be searched by name, structure and a series of abbreviations, drug code numbers, therapeutic categories or inhibited enzymes. Similarly, if you have ChemFinder, it can be used to browse and retrieve structures by their commercial names and paste into ChemDraw. For a brief subjective name-to-structure test see the ACD home page. As a whole, the structure-to-name service is a very useful feature for every organic chemist; conversion of name-to-structure is usually less practical: long and complicated names are difficult to enter without typo or syntax error, short names are usually quicker to enter immediately as graphics, this concerns the extension of atom labels (substituents) too, as discussed above. Apart from of ISIS/Draw, all of the programs can perceive aromaticity and replace double bonds with aromatic (delocalised ) rings.
Spectra and chromatograms A novelty in these programs is the spectral data publishing feature, spectrum interpretation and database management tools. UV, IR, NMR, MS spectra and chromatograms can be embedded into the documents and join with structures etc. The most versatile are DrawIt and ChemSketch, a lot of filters are available, respectively (available only when purchasing the appropriate ACD/Labs modules), thus, a wide range of formats arising from different instruments can be imported. ChemDraw supports JCAMP and Galactic files. The curves can be resized, zoomed, scaled, corrected, annotated, and peak list and tables are easy to create. Finally they can be embedded into the final document. Of course only formation and editing of the curves are possible and not basic manipulations, such as Fourier transformation of the FID signals. Full processing capabilities are available using the ACD/SpecManager product suite which is integrated into ChemSketch. All of the three applications enables the user to assign structures to spectra. One can then display the structure associated with a specific peak by placing the pointer on that peak. Before making any decisions, it is highly recommended to check that what spectrum and database formats are supported by the current versions. With the freely available NMR- or SpecViewer add-ons ChemSketch‘s capacity can be also extended to the handling of NMR, UV etc spectra of different origins: 
Different chemical and other adds It is not easy for the reviewer to decide what and how to include, because these extras are changing quickly and depending on the owned version (freeware or standard vs. pro vs. ultra versions etc.), sometimes add-ins can be installed only into the purchased version, sometimes they are free, sometimes they are to be purchased separately or available as an Internet-based service (see table 1. too). It is highly recommended to look for information at the home pages of the manufacturers before making decisions.Molecular weight, and constitution %: All of the programs. NMR:13C: KnowItAll, ChemDraw, ChemSketch (to be purchased or via I-Lab), ISIS/Draw (with ACD/Labs Add-ins for ISIS ) 1H: KnowItAll, ChemDraw, ChemSketch (to be purchased or via I-Lab), ISIS/Draw (with ACD/Labs Add-ins for ISIS ) 19F, 31P and 15N NMR: ChemSketch (to be purchased or via I-Lab) The chemical shifts are not ab initio calculated, but determined with the aid of the applied databases, therefore the precision of the results is a function of the included molecules. The 13C NMR module of the DrawIt/KnowItAll (if the full suite is installed) and ACD/CNMR can show molecules possessing analogue chemical environment to those of the carbons in question. ChemSketch has also developed this scheme into their NMR prediction modules through their "calculation protocol" environments. MS Fragmentation tools:
The MS fragmentation tool mimics the molecular fragmentation in a mass spectrometer, it allows the user to break existing structures across one or more bonds. ChemDraw, DrawIt, ChemSketch and Chemistry 4-D Draw have this tool; the first twoapplications have the most advanced one, it allows to fragment in zigzags and calculate the mass resulting from multiple fragment losses (if you need more, use ACD‘s MS Fragmenter or a similar package). IR: KnowItAll, ChemSketch (with UV-IR Manager add-on):Manipulation and comparison of IR spectra. Other chemical property prediction tools:ChemDraw: logP, CLogP, critical pressure, temperature and volume, Henry‘s constant, Gibbs energy, heat of formation, MP, BP, molrefraction. Some of these are available in the ultra version only ChemSketch: free macroscopic properties (molar refractivity and volume, parachor, surface tension, index of refraction, density, polarizability), logP, pKa, Hammett σ etc. Some of the features are available through ACD/I-Lab. Consult ACD-Labs home page for current details. DrawIt/KnowItAll: logP, logD, pKa, Rule of Five. These calculated properties are to be handled with critic.ChemBasic Goodies of ChemSketch: A bunch of handy utilities can be found in these extensions, among others handling of multipage documents, conversion to HTML, VRML or SDF formats, peptide, carbohydrate and nucleic acid builder. ACD/ChemPalm, ACD/ChemPocket of ChemSketch: These are applications for Pocket PC and Palm© OS-based PDAs (Personal Digital Assistants). They allow to view chemical structures and browse and search chemical databases containing structures.
Documentation An ample amount of printed documentation is included with ChemDraw (it is available in pdf format on the program CD as well). DrawIt and Chemistry 4-D Draw, ISIS/Draw and ChemSketch have no printed documentation (but are available in pdf and/or doc formats of the latter). The available on-line documentation (Help) is good in the case of ISIS/Draw, ChemSketch and Chemistry 4-D Draw, it is practically the same as the printed one in the case of ChemDraw. The Chemistry 4-D Lite Help documentation is incomplete, several modules have no descriptions at all, no information could be found about the so-called Plasmid modul even from the web site of the program.
Drawing programs and the Web Nowadays there are more and more applications (better to say browser plug-ins or Java applets), which can be used for the entering chemistry directly into the browser, for example to search an on-line database. A Java applet version of ChemSketch is available at no cost from the ACD website (via the ACD/Structure Drawing Applet). This is a full featured Java-based structure drawing editor including templates and periodic table. The afore-mentioned I-Lab add-on to ChemSketch is also an Internet-based service. The ChemDraw Plugin automatically turns the web browser into ChemDraw whenever a page containing an embedded ChemDraw document is encountered. However, we do not deal with this theme this time. Several Java applet versions are found among the programs mentioned in the next What else out there section, too.On browsing the different chemistry-related forums or lists, it turns out that many user faces the problem how to create an image from a chemical sketch to publish it on the web. It takes a few second for an advanced user, but problematic for the novice. Apart from ISIS/Draw and DrawIt, all of the reviewed programs support this. As a rule of thumb, never use the jpg format for sketches, but the gif format (or png) instead! To know more about the gif and jpg (jpeg) formats, read this sidebar.
Summary Apart from small corrections, no new features can already be added to the drawing functions of pure chemistry. Little additions and corrections are continuously made of course, especially database functionality, such as support for Markush structures, polymers etc. is enhanced – this in mind the developers are recently concentrating on the intelligent to-and-fro chemical naming modules, and tools for viewing and representing spectra of different formats.
What else out there? Beyond these five drawing software applications there are several others to be considered or for experimentation. They are freewares or can be purchased for a shareware category price. Some are highly sophisticated, some are simple, some are only in beta-phase or are not bug-free. Here are a few of them (no extensive tests were done): WinPLT 7.1   In the first part of the 90s the DOS based PLT was the masochists‘ drawing program with its dozens of dozens of keyboard shortcut combinations. It concentrates on drawing without the many bells-and-whistles of the above five programs. Advanced users could absolutely master the drawing. For example, the height, breadth, slant, and rotation of text could be freely and continuously changed, as well as the fine adjustment of the bond crossings and many other parameters. The Windows version is already more user-friendly, but unfortunately, some of the uniqueness of the original PLT had to sacrifice. Even so, beyond the standard Windows fonts allowing only italic and bold formattings a graphics font is available for free formatting (similarly to ChemDraw, WinPLT supports the rotation of atom labels and symbols). The technique and conception of drawing in PLT differs considerably from those in the above programs, this may feel odd for the new user (the program comes with ample help and tutorial). The presence of vector graphics strongly feels (the other programs try to conceal it by chemistry; the original PLT produced HPGL plotter files), but this allows unusual solutions, such as direct embedding of keto or sulfone groups to rings or text labels, or creating special bonds by dismantling bonds into lines and reformatting them (such as the up/down double bonds in the image) etc. It reads/writes only its own file format, can export to WMF, EMF, BMP, GIF, smoothed GIF and EPS graphical files or to the clipboard. Several other formats, e.g. MDL mol or rxn files can be converted to PLT format by Mol2Mol. In addition to chemical drawing, in the Windows version modules for incorporating NMR spectra and producing X-Y graphs have been included. Some unique features: on-click addition of several common moieties, such as carbonyls, CH2 groups with up/down bonds, etc; Bezier, sine, cosine, parabola, circle, Gaussian and Lorenzian curves are available; chemical slide-show (without Powerpoint) etc. Worth trying. URL: http://www.chem./areas/reich/plt/winplt.htm (Hans J. Reich) ChemPen A very useful application, different versions are available (NMR prediction, fast force field based geometry optimisation and 2D → 3D conversion). Worth trying.URL: http://www./ (Hilton Evans) XDrawChem 1.9.5 URL: http://xdrawchem./ (Bryan Herger) JChemPaint 2.0 Java based multiplatform, simple 2D drawing program, worth trying. Java applet version is available as well. Among others supports CML, SVG, Smiles and MDL MOL/SDF formats, and 13C NMR prediction.URL: http:///projects/jchempaint/ (JChemPaint Project)
MarvinSketch 3.5 MarvinSketch is an interesting Java based multiplatform application. Although it is only a basic 2D drawing software, it includes some features characteristic only on modelling softwares, for example coloring of the atoms by type or display in ball-and stick and CPK models. It is possible to import 3D molfiles (ISIS, Sybyl, PDB, xyz) or to use the 3D clean-up module. Only pure molecules can be drawn and saved/exported as molfiles. MarvinSketch is available as Java applet or application (bean) for developers and may serve as the graphical input module for example on-line databases (therefore query bond and atom types á la ISIS are also supported). It contains several calculation options (pKa, logP, logD, partial charge, H-bond donor-acceptor, topology analysis, polarizability etc). Sister program: MarvinView. Compared to the other drawing applications, it is unique in MarvinSketch that the image on the screen is slightly antialiased (eliminating of stair-step appearance of sloping or curved lines). Therefore MarvinSketch is excellent to draw molecules intended as images for web pages. It‘s unfortunate that practically no options can be found for styling (size and type of fonts, bond width etc.) - by adding more functionalities and options it would be a very useful editor for web images as well.URL: http://www./products.html (ChemAxon Ltd)
JME Editor 2004.10 
The simple and user friendly JME Molecular Editor is a free Java applet which allows to draw, edit and display molecules and reactions directly within an HTML page. The editor can generate or input SMILES, MDL mol/rxn or proprietary own formats of the created molecules. Its JME Professional version is not an applet, but a stand-alone Swing application. Only pure molecules, query structures, and reactions can be drawn and saved/exported as molfiles. Creation of substructure queries is also supported. JME is an excellent tool for developers and may serve as the graphical input module for example on-line databases or property calculation services.
The applet may be used also in a depiction mode to visualise molecules:  URL: http://www./jme (Peter Ertl, Novartis Pharma AG)
BKChem 0.9 BKChem is a free chemical 2D drawing program in developing phase, written in Python, therefore it is a multiplatform application (GNU/Linux, Windows). It has the basic drawing features. Supports CML and Adobe SVG graphics. The latter allows to embed good quality antialiased graphics into web pages (needs the Adobe SVG plugin).URL: http://www./bkchem/index.html (B. Kosata)
References 1) ISIS/Draw 2.5, MDL Informations System, 14600 Catalina Street, San-Leandro, California 94677, USA. URL: http://www.
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The editing of structural text is by far the least convenient in ISIS/Draw: the formation of structural text resembles to the era of Commodore and Sinclair Spectrum. Greek and Latin characters cannot be used mixed (for example in a substituent like "-O-α-D-arabinofuranosyl"). ChemSketch suffers also from the similar problem. Of course, the solution is simply to create a caption text, to position and group it with the parent structure. When in ISIS/Draw the font type or size is changed during the creation of a document, the program tries to remember what kind of font was used in the structures previously – as a result, sometimes two or even three different font-types or -styles are used automatically for the heteroatoms within the same structure. This constant bug is difficult to reproduce, but sometimes appears seemingly without any reason. In spite of ISIS/Draw, the parameters of structural and caption texts are not used globally in the other applications: five independent settings in DrawIt, two in the others are used instead, which is a much more user-friendly solution. The caption text editing properties are the best in ChemSketch and ChemDraw in the second place. 
