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Biochemistry: Substance & Reaction Searching

Substance Searching

Search for substances using a chemical identifier or by drawing the chemical structure. Below are some help resources on searching for substances in different databases.

SciFinder

Reaxys

ChemSpider

Markush Structure Searching

Markush structures are chemical structures that contain R-groups (variables). Markush structures often appear in patents, where their variable groups can be broadly defined. Below are some help resources on searching for Markush structures in SciFinder and Reaxys.

SciFinder

Reaxys

Reaction Searching

Some chemistry databases contain reactions. These can be found by searching directly for reactions. Reactions involving a particular substance can also be found from the substance details page in SciFinder and Reaxys.

SciFinder

Reaxys

About

Many chemistry databases may be searched by substance and/or by reaction. Each database handles this function differently but the principles are the same.

Chemical Identifiers

Chemical Name: Chemicals can have dozens of synonyms. Common types of chemical names include:

  • Common name

e.g. ibuprofen

  • Trade name

e.g. Advil

e.g. 2-(4-isobutylphenyl)propanoic acid

  • Other synonyms

e.g. list of synonyms for ibuprofen

Molecular Forumla: Be careful using molecular formula to search; many substances have the same molecular formula.

e.g. C13H18O2

CAS Registry Number: CAS Registry Numbers are unique chemical identifiers. CAS Numbers are proprietary identifiers maintained by Chemical Abstact Services (CAS), makers of SciFinder. Many chemistry databases make use of CAS Numbers.

e.g. 15687-27-1

International Chemical Identifier (InChI): InChI (pronounced IN-chee) is the non-proprietary IUPAC unique identifier for chemical substances. It encodes molecular information in machine and human-readable format. InChI is widely used by chemistry databases. A shorter version of InChI known as InChIKey (which is machine but not human-readable) may be more convenient for database searching.

e.g. InChI=1S/C13H18O2/c1-9(2)8-11-4-6-12(7-5-11)10(3)13(14)15/h4-7,9-10H,8H2,1-3H3,(H,14,15)

InChIKey: HEFNNWSXXWATRW-UHFFFAOYSA-N