Substances are at the heart of chemistry and of SciFinder.
Chemical Abstracts (SciFinder) has always placed a priority on identifying substances in the chemical literature.
SciFinder applies Roles to the substances it finds in the chemical literature. This helps researchers find articles in which the substance played a particular "role" such as Preparation, Uses, or Analytical Study.
Limiting a substance to the references in which it plays a particular Role can be a powerful way to focus a search. Preparation, Uses, and Analytical Study are the most useful Roles.
Substance Roles: Analytical Study; Biological Study; Combinatorial Study; Formation (Nonpreparative); Occurrence; Preparation; Process; Properties; Prophetic in Patents; Reactant or Reagent, and Uses.
Roles have been assigned to all substances in SciFinder since 1966.
Unlike other Roles, the Preparation Role has been consistently been assigned for all substances for all years. This makes finding literature reference to preparations fairly easy in SciFinder..
There are a few exceptions to these generalizations – all Roles for all years have assigned for a few major chemicals such as benzene, ethanol, and formaldehyde.
Three ways to search for preparations.
Explore reactions ... use the reaction drawing window
Explore substances ... choose references for Preparation role <= This is the best!!!
Explore references ... type in "preparation of [insert the CAS Registry Number] <= Usually just as good!
Entry points -- For Substances
SciFinder provides several ways to locate substance records. From a substance record you can quickly find literature in which the substance appears, often in specific Roles such as Preparation or Analytical Study.
Chemical structure -- Use the drawing window to search for a structure or a substructure
Name (under Substance Identifier) -- An excellent way to find a substance record. Usually you only get the substance you want, not isotopes or multicomponent substances. Compare an exact structure search for chlorobenzene with a name search in the Substance Identifier -- the latter finds only one substance while the former finds >1,000 substances..
CAS Registry Number (under Substance Identifier) -- This is quick way to find a substance record if you know the CAS Registry Number of a substance. Find up to 50 substances at one time using the Substance Identifier.
Molecular Formula -- This is the least helpful way to find a substance because many substances have the same MF.
Links from other parts of SciFinder -- Anytime a link is associated with a substance, it will take you to the substance record.
Markush structure -- Use the drawing window to search for more general structures that resemble the claims made in patents
What is a substance? This question is not as easy to answer as it might seem. SciFinder places substances in six general categories.
Bonds to metals are often ignored in structure searches.
To get more precise answers, Analyze Substances by Precision.
Incompletely defined substances
Reference lacks sufficient information
SciFinder treats sequences different than it does substances – even though the distinction is somewhat arbitrary. Most sequences consist of amino acids or nucleic acids.
Precision Analysis -- Check the box called "Precision Analysis" when you do substructure searches.
This is extremely valuable for inorganic substance substructure searches.
Inorganic substances -- SciFinder has a generous view of what might constitute a bond, especially in inorganic substances. SciFinder substructure searches often imagine a bond between atoms in different components of a multi-component substance (which frequently make little sense chemically). Precision Analysis allows you to restrict the search to "Conventional Structures" which will give you what was drawn in the structure search.
Why does SciFinder include "Non-conventional Structures" in substructure searches? SciFinder prefers to find "false hits" and have you remove them from an answer set rather than to miss results that might be helpful to you.
Organic substances -- SciFinder substructure searches of organic substances can find substances in which the a ketone migrates into enol and then into a double bond. Choosing "Conventional Structures" in Precision Analysis will focus on structures that more closely match what was drawn.
Use SciFinder's Analyze tool when you want to know more about the results of a Structure Search. Use the Refine tool when you know how you want to limit the Structure Search.
Analyze => When you want to know more before you apply search limits
Substance role (the default sort}
Refine => When you know how you want to limit a search
Atom attachment => Click on an atom in a structure to see which elements are attached