the chemical information instructor
edited by
ARLEENSOMERV~LLE Carisan Library University of Rochester Rochester, NY 14627
Information Sources for Organic Chemistry, 3 Arleen N. Somerville Carlson Library, University of Rochester, Rochester, NY 14627 Knowledge and understanding of the major information sources enable students and professional chemists to find needed information efficientlv and on a timelv basis. Learning to select the optimum~sourcesand use them efficiently is an integral part of chemical literacy. This article is the third in a series that provides readyto-use lecture material about organic chemistry information sources. a chart that links sources with ouestions which is suikble for distribution to students, an'd a set of practice questions. This article focusses on sources for reagents and solvents. Part 1discussed sources for name reactions and t w e s of reaction:' Part 2 covered functional group chemis&y? Future articles will describe sources especiallv of questions. - helpful - in answering- other categories Organic chemists have information questions characteristic of their research. These questions generally fall into either of two, occasionally overlapping, groups: those related to the synthesis or preparation of substances, or those related to mechanistic or physical organic chemistry The former group might include name reactions, reaction types, functional group transformations, solvents and reagents, synthesis or reactions of a class of compounds or specific compounds, and preparative techniques. Questions in the second group might include problems involving the relation of structure to kinetics, or equilibria, the structure of molecules or transition states, types of reaction mechanisms, spectroscopic aspects of organic chemistry, etc. Some questions, such as those about stereochemistry, may arise under either of the two groups, depending on the context or major thrust of the query. As in the fxst two parts of the series, this article offers a chart that lists these catemries of oreanic chemistrv " aues* tions and suggests some optimum or typical sources. The reader should be aware that such source lists are necessarily representative rather than exhaustive, that certain sources may be relevant to more than one question category, and that some degree of judgment or prioritization must be exercised in the use of these lists. While the list of sources is not meant to be comprehensive, this chart helps develop efficient searching skills and chemical information literacy. The full list is suitable for use with upper level undergraduates, graduate students, and professional chemists. For other undergraduates, the instructor will want to include selective sources relevant to their information questions. I n using this chart, chemists should identify the various ways that their questions can best be answered using the tabulated categories as guides. One could thus ask about a synthesis question, is a specific functional group transformation involved? Would the use of a name reaction be
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'Somewde. A. S. J. Chem. Educ. 1991.68.553-561 2S~mew#l e. A. S J Cnem €dm. 1991.68.842-853.
helpful? Is a general type of reaction likely to be required? What reagent would be best? Has a similar substance been synthesized? From such a n analysis one can proceed to the chart to determine which sources to examine first. In certain cases more than one category should be wnsulted. For example, for a functional group interconversion, one can start a search under functional transformations, but one might supplement this search using sources listed under reaction type or possibly under class of wmpounds. Specific features of manv sources are described andillustrated here, g o that the information can be used for lectures. Complete h i h l i o m ~ h i cinformation is 'provided in an alphabetic list atiheAendof the article. Searching by Reagent A major category of common questions asked by synthetic organic chemists involves reagents used to achieve specific reactions and products. Chemists may ask: Has dimethyl sulfoxide been used as a reagent in oxidation reactions similar to the reaction we are working on? or Where can 1 find information ahnut rhe commercial availability and use of ethyl vinyl cthcr for thc synthesis of alde hydw hy the Clmsen Renrrangement? or Where can I find a discussion of the use of hydrogen peroxide as a reagent in the Baeyer-Wliger oxidation of ketones?
Certain reference handbooks, books, and computer databases answer these questions very well. General Sources
1.Fieser. Reagents for Organic Synthesis. The long-rimr premier anurcr for infnrmntion nbout rragcnts. An important source for all chemists, from undergraduates to professional chemists. In most cases it is efficient to check Fieser first, because it is the most comprehensive and up-to-datesource. The first and most extensive volume in this continuing series was published in 1967. Fifteen volumes have appeared since then. Entries are arranged alphabetically by reagent name. Entries list reaction scheme(s),along with brief, concise comments about preferred methods of preparation and examples of significant uses. References are given to journal articles that provide additional experimental details. Each volume includes an "Index of Reagents According to Type" of reaction, such as ene reactions, fluorination, and Diels-Alder. A new Collective Index far Volumes 1-12 (1990) includes an extensive "Reaeents Index" (an al~habetieallist of reagents). Only v & n e and page nuiben are listed in the Reagents Index, so each volume and page number at a reagententrymustbe checked. Volume 69 Number 5 May 1992
379
F~gureI. Entry for pertrifl~oroacet~c acid in Collect ve ndex. Fieser's Reagents lor OrganC Synfhesrs (Reproduced w th permission of Wiley)
emrv*,
d n . emmom a d ~ u u s 'found lhnt psrmn~omaee8ic m i d i m most acyclic ketones smoothly and acid. in convast to olher -ids, rapidly to n l c n in uccllcnt yicldr in initial V i a ram= J-LOP. ofmstensl v- lost
1. PmtaeUng grovp t--
I.T n n s ~3nylaUU 3. Bynthemis
d ddehydes by'
........................................................................... PRKP*PbROW:
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-s-t on be ~ m - d by r+acUw acetalddehydr. emmol and HCI 1 C. snd D. ~ottemn.J. *I. C L ~ . a,. (1846). 88, IZW I .
1. Thr
mra
........................................................................... PnBC*URO":
v r c n f in ihc reaction mixture had to bc m m v d wilh Cinrd's p e n t P. and the yield M not high. Howcver. mclhyl cyelopmpyl ketone is mmplccdy incn to p(*nroic acid. Trinvomssais acid pmbably fvnclions a cstnlys$ because of ita Itmngacidily:
........................................................................... RBPBRBNCm 1. L. Paquette. H. Sehostaraz and 0 . An-.
J.
Am. D-.%., (1981). 103.
6515.
High yields are obtained alm in the oxidation dcyclic LctoneloUlc ring.cxpmdcd lael~"~~.'
311
Figure 2. Information about use of pertrifluoroacetic acid in the Baeyer-Villiger reaction found in Vol.1, Fieser's Reagents for Organic Synthesis. (Reproduced with permission of Wiley.)
Figure 3. First of two pages on ethyl vinyl ether from Mundy, Name Reactions and Reagents in Organic Chemistry (Reproduced with permission of Wiley.)
To find out how to prepare and use pertrifluomacetic acid (peroxytrifluoroaeetic acid) in the Baeyer-Villiger reaction, cheek peroxytrifluoroacetic acid in the "Reagents Index" of the Collective Index. A"= reference" specifies that the information is found under Trifluoroperacetic Acid. (See Fig. 1)This reagent is found in 10 entries. The entry in Volume 1on DD . . 823-24 (Fie. 2) is a useful answer to the question. References R and 9 refer to a n ~ r l e sin Journal of the A m n m n Chemtcai S m & , Tetrahedron, and Joummi of Organic Chemishy.
2. House. Modern Synthetic Reactions Written for advanced undergraduates and beginning graduate students. Arather detailed survey of many important syntheticmethods commonly used. An essential reference hook for all new synthetic chemists, limited only by its 1912 publication
date.
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Information provided: reaction mechanism, stereochemistay; reaction conditions, including choice of reagents; and examples of the reaction. For detailed experimental pmcedures, readers are referred to journal articles and other handbooks. Multiple references to the same reaction are usually provided. Chapters discuss reactions, such a s metal hydride reduction, oxidation, halogenation, alkylation, aldol condensation, acylation. An extensive subject index provides quick access to information.
380
Journal
of Chemical Education
lure 4. Second page on ethyl vinyl ether from Mundy, Name ReacIns and Reagents in Organic Chemistry (Reproduced with permism of Wiley.)
To find information on dimethyl sulfoxide in oxidation reactions, check in the index under its name. This refers to an extensive discussion on pp 415-21.
3. Mundy. N a m e Reactions a n d Reagents in Organic
1991 includes several entries. Figure 5 shows the entry from Vol. 42, No. 554. Additional experimental details are foundin articles listed in Tetrahedron Letters and Journal of the American Chemical Society.
Chemistry.
An excellent, concise, easy to scan reference source. The hook is divided into two main sections: name reactions. and most commonly used reagents in organic chemistry Far each reagent, two pagcs provide the care mfurmation. To locate relevant pages, check the Index under the reagent name, or the reaction name. To locate reagents used in the Claisen Rearrangement, look under "Claisen Rearrangement" in the Index. Figures 3 and 4 show the two pages for ethyl vinyl ether. Figure 3 provides: the structure; selected physical data such as melting paint and molecular weight; references to Fieser's Reagents for Organic Synthesis and to March's textbook Advanced Organic Chemistry; some of the major uses (note that synthesis of aldehydes by the Claisen Rearrangement is listed); preparation; some precautions; notes; and references to examples of uses. Figure 4 lists five examples where ethyl vinyl ether is used a s a reagent, using reaction diagrams. The triangles, which refer to notes on the previous page, indieate Claisen Rearrangement reactions. The squares refer to two types of major uses: trans vinylation, and synthesis of aldehydes hy Claisen Rearrangement. The circled numbers link the examples to the references on the previous page.
4. Comprehensiue Organic Chemistry A reference guide for students and professional chemists puhlished in 1979. Five volumes describe the properties and reactions of the important classes of organic compounds. Volume 6 includes several indexes, one of which is the Reagent Index. Sometimes Reagent Index entries refer to pages in Volumes 1 4 and sometimes entries list journal articles, which should he checked for experimental details. To locate information about a specific reagent, such a s dimethylformamide (DMF) used in the synthesis of acid chlorides, check the Reagent Index in Volume 6. Because DMF is a commonly used reagent, the several pages of subheadings should he checked to locate the correct entry. The acid chloride synthesis application is found under "Dimethylformamide-thionyl chloride". Three references to journal articles are listed, which should he read for experimental details. When checking for use of hydrogen pemxide in the hydmlysis of nitriles, the index refers to Volume 2, p 542 of this set. Several sentences d i m s the use of HzOz Two journal references are given if more detail is needed.
5. Theilheimer. Synthetic Methods of Organic Chemistry. A reference source for locating information about substances used as reagents, as well as starting materials, products, and solvents. Published annuallv since 1946. Rinted in English. Quick evaluation oirelevance is facilitated hy intries that p m vide: structures of starting materials, intermediates, products, reagents and catalysts, text and cade description of reaction; brief description of experimental canditions a n d yield; and journal reference for full experimental details. Information is selected mostly fmm 180 major chemistry journals. Since 1975, information in the annual Theilheimer volumes is derived from monthly issues of Journal ofSynthetic Methods. A full description of Theilheimer's use is found in Part 2'. Information about a reaeent is located hv checking the index. Each annual volume h a i a detailed index, which iscumulated aRer five years. To locate articles about triethylhorane a s a reagent, check the name in the indexes, starting with the most recent volumes and working backward. The 5-year index for 1987-
Figure 5. Entry that shows a use of triethylborane a s a reagent, found
in Theilheimer, SyntheticMethodsof Oganic Chemistry, Vol. 42. (Reproduced with permission of Karger.)
6. 100 Modern Reagents Servesasareferencesoureefor 100reagentsusedinorganic synthesis. (Note: These 100 reagents are a small selection of the manv commonlv used reaeents.) Entries list chemical a n i physical'bata isuch a s molecular weight, boiling and melting paints, density and refractive index); safety and handling information; commercial availability; preparative methods; types of reactions in which it is used; selected examples of recent applications, along with journal references: and Chemical Abstracts service Registry Number. To locate information about tert-hutvl hvdrooeroxide as a r e agent, check the dphahetlc lwmg on pp 35-36. Ftgure 6 shows p 35 Not shown 1s p 36, whwh provrdes three re cent examples of its use as a reagent by graphically displaying t h e reaction a n d providing t h e literature reference.
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18. terkBulyl hydmpemxide (TBHP) 75-91-2 Hydmproridg I.ldi&ylahyl
MoCOOH 90.12
89% (k.) 6=c as01& I , " '
13969 Flnvnabb. hidim.Humful. IniaIinx a cyw and stin. S t m e bClDx 792. Liabk mcrpladc when &-
lillcd
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F~gure6. One of two pages of mformauon about 1-o~tyl nydroperox. ~ d founa e n 100 Modern Reagents (ReprW~cedwltn permasson of Roya Soclely of Chem sty I
Volume 69
Number5 May 1992
381
7.Pizey. Synthetic Reagents An on-going series of bwks, each of which provide extensive chapters on reactions and uses of reagents. Volume 6 (most recent volume) covers: chloramine-T hydro gen peroxide, and polyphosphoric acid. Other volumes include, for example, dimethylformamide, lithium aluminum hvdride, diborane,. magnesium dioxide. lead tetraacetate.and s&urvl chloride. The deThe hvdmeen chaoier in Volume 6 is tvoical. . .. n&oxide , , tailed tsble-of-contentsfor the chapter clearly and qu~ekly shmvi the coverage and helps select relevant pages quickly. Sections cover resctmns wlth alkenes, aldehydes, ketones, carboxylie acids, alcohols, amines, sulfur compounds, nitriles, aromatic compounds, heteraromatic compounds, and natural products. An extensive bibliography of 425 articles accompanies the text.
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8. Aldrich CataloglHandbook of Fine Chemicals "Aldrich" is an examole of a cataloe of commerciallv available chemicals that include* proprnres data and references to major sources of infonnation. This book is usually kept close at hand in many laboratories. Chemicals, including reagents, are arranged alphabetically; there are many cross references, including from acryonyms commonly used for reagents, solvents, etc. Includes a molecular formula index, if a check for the substance bv name is not oroductive. Provides: property data such as melting and boiling points; density; safety and tcrnc information such as RTECS no.. terms that describe toxicity, and references to safety compendia; molecular formula; Chemical Abstracts Service No.; and structures for more comulicated subRegistry stances. Provides references to such sources as Merck Znder, IR and NMR spectra, Beilstein, Fieser's Reagents for Organic Synthesis, and toxicity compilations. To locate information about dimethyl sulfoxide, look under the name in the alphabetic listing. AYseereference" sends the reader to methyl sulfoxide. The entry under methyl sulfoxide is shown in Figure 7. This quick check provides a number of references to Fieser's series, a s well as to Beilstein and the Merck Index. ~
*Y".".rrri>ans*,.n"L* mJID ra a
A,"',
u 1 I., ds, look in the Reakwnt Index under benzyl rhlorlde and cheek the reaction schemes on the pages listed. An example that might answer the question occurs on p 93 (Fig. 8).
12. Hase. Umpoled Synthons An excellent, thorough survey far research chemists who needto find umpoled Le., polarity-reversed) building blocks inorganic synthesis. Provides a catalog of "actual" reagents which are reactive equivalents of such synthons as T H O , -RC=O, ROC-=O +C-C=O, and-C-C-CO. There are six descriptive chapters and a tabular survey listing approximately 50 types of synthons (Figure 9 shows the tahle-of-contents for a portion of the synthon listing). Each entry in the tabular survey specifies a particular synthon equivalent, types of reaction partner, yields, reaction conditions, and literature references. Figure 10 shows a typical entry (MeS)3CH is the actual compound which serves as the equivalent of the synthon TOOH. Column 2 lists the type of reaction partner, which in this case is designated by #62. (Note: a table a t the beginning of the tabular survey defines #62 as C=C-COOR (1,4 addition to).) The letter A indicates a hieh reaction vield. . , i.e..,
