REVIEWS The Loglchem Organic Inference Program F. R. Burden, Chemsofl (Vic.), 109 Arnold St.. Cariton North. Victoria, 3054, Australia
Hardware: IBM PC or compatible with at least SlPK of RAM Components: 1 disk and User's Manual Level and Subject: Organic chemistry Cost: Contact F. R. Burden, Chemistry Dept.. Monash University, Clayton, Vic. 3168, Australia
Summary Ratings: categow: Ease of h: Subject m n s r Content: Pedamic Value:
Student Reaction:
Below Average Below Average Pmr Poor
Review Features The Logichem Organic Inference Program is designed to provide a data hase of reactions between organic chemicah. The program is written in Turbo Pascal for use on the IBM PC/XT/AT series of personal computers with a memory of a t least 512 kBytes. The program takes as input two molecules and lists the possible products determined by a set of reaction rules built into the program. The manual accompanying this program suggests that it is marketed for "those engaged in the teaching or learning of organic -Reviewed In This
chemistry since the program represents an easilv consulted version of a textbook." The manual adds "it may he of some interest to those engaged with expert systems and the representation of complex knowledge." The program is not intended to assist in developing synthetic strategies or pathways for multistep reaction sequences. The products of one reaction step must be used as the innut to the next reaction if a multisteo reaction is being considered. The heart of the program is a set of functional groups and ruler to determine correct reactions between functional groups. According to the manual, it is possihle for the user to enhance the program's usefulness by adding functional groups and reaction rules. The program first asks for the chemical formulas of two reactine molecules. which can b? entered from t h r keyboard br dirk using symholr given in the manual. The input iaatrarghtforward for straight chain hgdrocarbons with single functional groups and confusing for highly branched polyfunctional or cyclic molecules, since alpbanumeric characters on a single line must be used to represent three-dimensional structures. The program then ~vrerteinrthe possible reacting functional group9 and consults the list of rules to generate possible outwmea for the reaction in question. I t presents a menu from which various choices can be made. The possihle reactions can be shown sequentially, with help windows explaining the products that are shown and giving references to oaee numbers in the fifth edition of 0rganiE ?hemistry hy Morrison and Boyd for further explanaiion. Accompanying the program is a 31-page manual that attempts to describe how the program works, gives several sample reactions, and explains the functional group and rule coding.
Student Reactlon The program was given as an option to a second-year organic chemistry class near the end of their second term of study. Students used the program on several IBM PC/ XT computers and also on several IBM clones. In general, the students found the program confusing and inaccessible. Very few of the reactions they tried to input to check the program existed in the data hase, and in some cases the nroducts eiven were either misleadine for an.introductbrv,organic uhemirtry atudent or simply wrong. The students who tried the program unaminously agreed that it would not he particularly helpful in reviewing or studying organic reactions without considerable expansion of the current data base of reactions, and refinement of the mechanisms for entering reactants. Students found the colors oleasine when using a color monitor, although several atudents suggested that the programmer could have been more consistent in using certain colors for particular types of instructions. The help windows provided the students with essential elaboration of reactions, and the references to a textbook were indispensahle for the explanationof major and subtle points ahout the reactions shown. Error trapping in the program is certainly not foolproof. For example, one user noticed that when a molecule is entered from the keyboard, if t h e cursor is accidentally moved beyond the beginning of the strueture, the computer freezes and has to he rebooted. This freezing problem was tested and confirmed on several different computers. ~
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Overall Assessment There is an important place for aprogram with the stated purposes of the Logichem Organic Inference Program. As others who (Continued on page AI30)
Issue Revlewer
Computer Learning Package F. R. Burden, The Logichem Organic Inference Program
Peter G. Mahaffy
A129
Frederick A. Bettleheim and Jerry March, Introduction to General, Organic, and Biochemistry, Second Edition H Stephen Stoker, Chemistry: A Science for Today Douglas J. Raber and Nancy K. Raber, Organic Chemistry Thomas H Lowry, and Kathleen Schueller, Mechanism and Theory in Organic Chemistry, Third Edition Monographs New Volumes in Continuing Series
David E. Horn Lewis A. Walker Juan F. Villa Harold M. Bell Henry E. Baumgarten
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Volume 66
Number 4
April 1989
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have attempted to computerize data bases involving reactions between three-dimensional molecules have discovered, the prohlems of representing structures and developing suitable algorithms for reactions are formidable. Although the author of this program has made a good start a t developing some of the codes and algorithms, the program does not yet meet its stated goals. Whatever it is, it is certainly not an "easily consultedversion of s textbook". I found the program of little value for my own use in its present form, and I would not distribute it to an organic chemistry class because of ambiguities and errors in the program and accompanying documentation. Several examples illustrate the earelessness with which the documentation was put together. The manual begins with the ststement (?) "This program is designed to show you a wide range of organic chemicals react and under what conditions." Under the section entitled "Hands an," the first example given is the reaction of 2-chloropropionic acid with ethanol. Under the name 2-chloropropionic aeid is drawn the formula for 3chlorohutanoic acid with a pentavalent carbon a t C3! On the next page of the manual, the user discovers that the structure being entered is really 3-chloropropionic acid. After the two reactants (3-chloropropionic aeid and ethanol) are entered into the computer, the first product suggested by the program is 3-ethanypropionic acid, the product of a Williamson synthesis of ethers in the presence of sodium hydroxide. The students who tried this example were (rightly) confused about why the ethoxide did not simply deprotonate the carhoxylic acid. The algorithms used to determine what constitutes a "correct" reaction are simply not sophisticated enough to make this program useful pedagogically. For example: The program lists one of the productsof the reaction between chlorohenzene and benzene in the presence of aluminum chloride as biphenyl and refers the user to the appropriate page in Morrison and Boyd, which states unequivocally that Friedel-Crafts alkylation does not work on aryl halides. In the addition of HBr to l-propene in the absence of peroxides, the first product given by the program is l-hromopropane. After the product is shown, a help window appears which explains that inMarkovnikov Addition, "the hydrogen of the acid attaches itself to the carbon that already holds the greater number of hydrogens". The second possible reaction that is shown is the correct one, 2-hromoprapane. In the addition of bromine to 2-hutene, the organic product is shown as 2,3-dihromohutane, with no mention of the stereochemistry of addition involving an intermediate cyclic hramonium ion. I could find no way of specifying cis- or tram-2-hutene as a starting material. The addition of bromine in water to an olefin makes no mention of either the regiochemistry or stereochemistry involved in the reaction. The addition of hydrogen to l-pentyne gives l-pentene as a product with the necessary "environment" requiring Pt,
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Journal
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Pd, or Ni. No differentration is made between the catalysts used fm hydrugenation of olefins and alkynes. Sodium ethoxide and many other ionic reagents are not included in the data hase, making it very difficult for an introductory organic student to practice nucleophilic substitution and elimination reactions. Users could, of course, add such reagents to the data hase. In summary, I cannot recommend this program in its present form. If the data hase were considerably expanded, and if some mechanism far taking into account the stereochemistry of reacting molecules could he introduced, the program would serve a useful purpose. Tremendous advances have been made in the last five years in the computer representation of three-dimensional chemical structures. Perhaps an attempt could he made to couple some of the useful algorithms contained in this program with a more sophisticated approach to entering and graphically representing the three-dimensional structures of reacting molecules. Peter G. Mahaffv
The chapters on organic and hiochemistry cannot he faulted as to the choice of material or the coverage of the material. The coverage of the general chemistry material is not as well done. Chapters 1(Matter, Energy and Measurement) and 9 (Nuclear Chemistry) seemed especially well written for a tent of this type. If there is a weak chapter, then it must he chapter 7 (Reaction Rates and Equilibrium). If there is a topic that was relatively neglected, then it would he thermodynamics which, in general terms, would he useful to students. Does this text attain the goals its authors set forth in the orefaee? We think it does. It especially attains the goal of msintn~ning student interert while cwering n, many ditierent chemical topics. We assume thnt the text will he used for a two-semester sequence. We heartily recommend this text for its intended audience. David E. Horn and Lewis A. Walker Goucher College, Towson. MD 21204
Chemistry: A S c i e n c e for Today H. Stephen Stoker. MacMillan: New York, NY, 1989. xi 884 pp. Figs. and tables. 20.8 X 23.9 cm.
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Iniroduction to General, Organlc, a n d Blochemlstry, S e c o n d Edltion Frederick A. Benelheim and Jerry March. SaundersCollege Publishing: Philadelphia, PA. 1988. xxix 633 pp. Figs. and tables. 20.5 X 26 cm.
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Writing a text for such a broad range of chemical topics is an ambitious undertaking. Overall, we would say that the authors did a tremendous job with this text. In any such hroad-ranging text there must he choices of what to include and what to omit of the material usually covered in standard courses assigned to this range of topics. The choices of one teacher would not he the same as those of another The choice- these au. rhors have made would appear tu be about deal, especially for a c l a r ~ o highly f talented students. The physical appearance and first impression made by the text is excellent. The text is easy toread. The photographs are not only handsome hut also they are appropriate teachine tools as are the comments made in the attractive wide mareins of na~er. -- the .-~. r-m... The boxed sections of material are well done and helpful to student understanding. Review and key term sections a t the end of each chapter are another plus. The prohlems at the end of the chapters are well arranged according to the material covered in the chapter, and there is asection of starred problems that are more difficult and arranged randomly according to materialwell done! There is a good index. The answer section is necessary, hut the authors resisted the temptation to answer all the questions and left some to test the confidence of the students. There is a good index, hut a few appendices containing tables of data would he a welcome improvement.
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Chemistry: A Science for Today is divided into three sections and 24 chapters. The first section consists of seven chapters and is dedicated to the classical inorganic topics such as handing, balancing of equations and mole problems. The second section, with three chapters, deals with the properties of the states of matter, including gases, eolligative properties and acid-base behavior. The last section has 15 chapters and is dedieated to the "chemistry in the modern world", including four chapters in inorganic descriptive chemistry, one chapter in nudear chemistry, three in organic chemistry, two in hiochemistrv. .. and two in oollution. Given the topics presented in the third section and itz magnitude compared tcr the frrst two RCCtioni, it seems hrical to have divrded it into two sections, one dealing with organic and biochemistry, and one dealing with deseriptive topics in general. The author achieved his objective of writing a text "primarily designed for a oneterm course.. .for nonscience majors". This hook is well written, at the correct level for a beginning student, is very clear in the concepts and ideas presented, and is not verbose. The author's apparent secondary oh.to provide a foundation for furjective, ther study in chemistry"is also achieved. To do this, he covers the topics to a greater depth than necessary in a one-semester terminal course hut does not burden the student with superfluous material. This reviewer feels that an instructor can easily adapt the hook to either of the objectives by skipping sections or by slightly supplementing the material. I t should he mentioned, though, that some of the concepts in this hook are presented in a very succinct fashion, such as dynamic equilibrium, which only takes six lines p. 239. But, even this brevity is
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