Finding a Method of Synthesis for the CH224 literature searching lab
Sources of information on Preparation or Synthesis
Finding syntheses is a central task in organic chemistry. For simple, common chemicals, numerous synthesis methods have already been discovered. You wouldn’t want to spend costly time in the lab developing a new method until you knew what was already out there. The good news is that there are some really great tools for this task. The bad news is that they require a bit of effort to learn how to use them.
The sources in this section cite scholarly journal articles about methods of preparation (also known as synthesis) of your compound. You need to locate the article itself to learn about the method of synthesis. (What is a "scholarly journal"?) The NCSU Libraries will have most of the journal articles you need to refer to. The steps below outline the process of finding these journals.
Two outstanding databases for this task are Reaxys or SciFinder. Either works, both have a learning curve. (Chemistry majors will find these more and more useful in later classes or when doing research and should definitely take the time to try one or both out.) Reaxys does not require a user account and synthesis results are easy to find, so it is recommended.
Using Reaxys to locate a synthesis reference
Reaxys is a recommended database for finding synthesis references.
First, search for your compound:
- Make sure the Substances and Properties tab is selected.
- In the Properties (Form-based) tab, expand "Substance Data".
- Expand "Identification Data".
- Type the CAS number into the box labeled "CAS Registry number". The form provides an autocomplete function to help find values.
- Click Search.
In the search results, you will see a column of data related to preparation methods. Reaxys will report the number of preparations found, among total reactions.
Click the number of preparations to list them. Reaxys provides details, sometimes including a detailed reaction, yield, solvents, and references to the original source articles. Click Get Full Text or the FindText@NCSU link to find the article.
Understanding search results
Reaxys is presenting us with a list of journal articles that contain reaction information in which our selected chemical was a product (in other words, it was synthesized using this reaction). Reaxys also diagrams the reaction of interest with any reactants, reagents, catalysts, steps, solvents, and stages.
Tip: Older methods might be easier to work with.
- Since the lab assignment requires ANY synthesis method (not, say, a research question where you want the latest method, or one involving a particular reagent), you can scan through the results to find one that will be a little easier to work with. Journal articles can be long, difficult reads, so it can be helpful to look for older methods (sort the list by Publication Year and jump to the last page of results). Older articles may describe the method in a more straightforward manner. Obviously the older the method, the greater chance the synthesis has been superceded by newer methods--but we're not worrying about that for this lab. You can also avoid non-English articles for the purposes of this lab.
Tip: You may need to look through a few different articles before you find one that is clear.
- You will find articles where the actual methodology used might not be clear for one specific chemical. The synthesis method may only be implied, speaking for a more general class of chemicals. Depending on the nature of your research, this could be fine or you may want to look for alternate articles that are easier to follow.
Click Get Full Text or the FindText@NCSU link to find the article. You will be able to get to it if (1) the Libraries subscribe to the journal, and (2) full text is online. This will be true for most (but NOT ALL) chemistry research, regardless of the age of the article. If you don't find it, try another, or note as much of the citation as you can see: article title, authors, journal title/source, volume/year, issue, page (or print or save it) and look for it manually. (Also feel free to ask a librarian for help locating the article you want.)
Other possible sources
The Dictionary of Organic Compounds, accessible through CHEMnetBASE (more information on CHEMnetBASE), is reliable for locating methods of synthesis.
- In CHEMnetBASE, select the Combined Chemical Dictionary (which includes the Dictionary of Organic Compounds). Search for your compound by CAS number.
- Click on the entry for your chemical, scroll to the end of the information page to see a bibliography of sources. Note any journal citations ending in (synth)—these are research articles which published a method of synthesis.
- You will want to find the Journal cited in step 2*. Search for journals by title. (Searching by abbreviation might work fine, but check the tip on abbrevations below if it doesn't).
- You should see any subscriptions we have to this journal. The citation you found in step 2 should have, at minimum, a volume number and page number. (It might also have a year, issue, author, or more.) Locate the article through the online subscription by browsing to the volume/year, issue if available, and page specified by the reference. Ask a librarian if you need help!
*Two things to look out for:
- Journal abbreviations. Many sources abbreviate journal titles and if you're not familiar with the journals the abbreviation can be difficult to decipher. Check this FAQ for common abbreviations, or look up others in CASSI.
- Reference to Organic Syntheses (abbreviated Org Syn). These are particularly easy to find and understand – skip steps 3 and 4 above. The citation will either be from the Collective or Annual volumes of Organic Syntheses. These can be looked up online at http://www.orgsyn.org/ --a free compendium. (Don’t start your search there. The search is very inexact and can be frustrating. But definitely use the site if you have a reference to these from steps 1-2 above. You can browse right to the volume and page number in that case.)
You may find that the Dictionary of Organic Compounds has few references, or they are not in English, or are otherwise proving difficult to find. You may also find that the article you find doesn't ultimately discuss your specific compound in a straightforward manner (the authors might be discussing a more general method of synthesis, for example.) SciFinder or Reaxys are more reliable sources--turn to them or try one of these other sources:
Other sources of syntheses:
- SciFinder - see especially the section on doing a search for methods of synthesis.
- Merck Index. Online via NCSU Libraries subscription. Also available in library print reference.
- Organic Syntheses. Freely available online. Collective Volumes I-X, also in print reference. Annual Volumes also in the bookstacks. Warning: searching directly in the online interface can be challenging! Search results will often seem unrelated to your search terms. This is a good lesson about poor search engines and interfaces. This resource IS very useful if you already know the volume and page you need from steps 1 & 2 above--you can browse right to it.
- Handbook of Reagents for Organic Synthesis. Some are online, all in print reference. (More information.)
- Other chemistry databases Available online through NCSU Libraries.
Try Web of Science (also known as Science Citation Index Expanded) or another chemistry database. Try searching for your chemical and synthesis (or preparation ) as search terms.
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