It is important to be aware that when you use the Reaction search feature in SciFinder-n, you are searching a different database than when you search for substances. Substance searching uses the REGISTRY file of over 175 million substances (approximately 100 million of which are simple organic and inorganic substances), covering the literature from 1907 to present, plus selected earlier references.
CASREACT, on the other hand, is more focused. It covers selected journal articles in organic chemistry (1840-present) and organic chemistry patents (1982-present). It indexes EVERY single-step and multi-step reaction described in the papers, including reactants, reagents and products, with yield information where available. Recently, reaction data from the Wiley reference works, Organic Reactions, Organic Syntheses and Enccyclopedia of Reagents for Organic Synthesis were added to the file. At present Dec. 2020), over 132 million reactions are included in CASREACT, with over 150,000 new reactions added per week.
Therefore, when searching for organic reaction information, if a truly comprehensive search is needed, both Reaction Searching and the other two approaches mentioned above should be employed. Reaction Searching alone is very detailed for organic reactions, but covers selected journals and patents only. Substance Searching is less powerful, but will extend your search to a wider range of source documents. Research Topic searching may pick up some additional reactions from the 1907-1966 literature.
Finally, remember that the CASREACT database does not index reactions by "name reactions", so you can't use "Diels-Alder" or "Heck reaction" in a reaction search as such. However...you can do a reaction search, Get References and then refine the references for the "name reaction" you're looking for or you can do a Research Topic search for the desired name reaction, then Get Reactions, and Refine the resulting set of reactions by a further Substance or Reaction search.
As seen above, it is easy to work from a substance record to reactions in which that substance is a product. But you can also achieve more specificity by drawing both reacants and prodcuts in a single query. Let's say I am looking for reactions which will transform aryl amines to nitro=aryls, while preserving an unreacted amine group elsewhere in the molecule. I start be drawing the basic reactant and product molecules. Note that since I am modifying the amine group and the nitro group, I cannot use the shortcuts for these groups, but mus draw them out fully.
Now I use the Reaction Arrow tool to specify which is the reactant and which the product. Click and hold the cursor near the reactant, and drag toward the product. With the arrow drawn, note how the reaction roles are now listed below each structure. If you wanted to change a role, you could use the Reaction Role tool, click on the structure and reassign.
Now I wish to specify that the amino nitrogen in the reactant becomes the nitro nitrogen in the product, To do that, I use the Map Atoms tool. Select the tool, then click first on the reactant nitrogen, then on the product nitrogen. Note that each is now labeled with a 1. Map Atoms can be used repeadedly for multiple atoms if necessary. If my reaction had bonds being formed or broken without atoms being added or lost, as in a Dield-Alder reaction, I could use the Map Bonds tool to indicate which bonds were being changed.
Now I'm ready to search. I click OK, to transfer the rection diagram to the query box, the click the Search icon and get my initial reaction search results. Below, I have selected the Substructure answers, as I wish to take the larger answer set and Filter the reults to get some very specifc reaction information.
First, I want to get some detailed instructions right away, so I finter to reactions with MethodsNow procedures. .I also want high yield reactions, so I then select Yield 90-100%. As you see below, I'm down to 117 reactions.
I'm not quite done. I also have an amine group elsewhere in my reactant that I don't want oxidized. So I take a look at the Non-participating Functional Groups filter, look at the whole set, and search for "amine". If you check the numbers associated with each group, you will see that "Amine" includes Primary amine", "Secondary amine" and "Tertiary amine", but selecting all those groups does not hurt my results.
I select all the terms that mention "amine" and click Apply. and now I'm down to 14 reactions.
Now, if I wish, I can take a look at some of the other filters, like Catalyst ,Solvent and Reaction Notes to see if I wish to refine further. I might want to avoid expensive palladium catalysts, so I can Exclude them or I might want a reaction I can carry out in water to avoid polluting solvents, or I might find the notion of a microwave stimulated reaction interesting.
Here's the reaction detail for one of the reactions we found:
Reaction similarity searches are done in the same way as other reaction searches. Simiarity is defined in three categories:
Below is an example from a reaction similarity search:
This feature of SciFinder-n allows you to create a synthesis plan for either known or hitherto unknown molecules with tremendous control over the synthesis steps. For known substances, you may access the Retrosynthesis tool from the substance record, or, for known or predicted substances, you may draw the structure with a version of usual structure drawing tool. Note that some of the structure drawing options are unavailable, because you are drawing an exact structure, not a substructure, similarity or reaction search.
For a known molecule, all you need to do is find the substance using any of the substance search methods, then click on the structure diagram to pull up the Quick View. Below is the Quick View for the drug, glipizide.
Note the fourth option on the left, Start Retrosynthetic Analysis. You can click on that to begin the process. The first time you use the system, you'll see the pop-up message below:
After clicking Create Retrosynthesis Plan, here's the opening screen of a retrosynthetic plan for glipizide, showing only experimentally verified reaction steps.
Here are some of the significant features to note:
To create a retrosynthesis plan for a hypothetical molecule, open the Substance drawing window, draw your molecule, click OK, and then switch the query option to Reactions. You should see a screen like this:
You can click on Create Retrosynthesis Plan directly, or go to Set Plan Options first. Note that in the absence of an experimental synthesis for your molecule, the predicted syntheses may take a relatively long time to generate. However, you can log out, and the system will continue working. When the predictive retrosynthetic plan is complete, you'll get an e-mail. Log back into SciFinder-n, go into your Search History at the lower part of your home page and click on Open Plan.
Here's the result on a hypothetical trifluoromethyl derivative of glipizide.
© 2022 Charles F. Huber
This work by Charles F. Huber is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Based on a work at guides.library.ucsb.edu
SciFinder-m screenshots are copyright © 2022 American Chemical Society and are used under fair use for educational purposes only.