Chemical reactions like
Reactant → Intermediate → Product
are of great interest. There are special reaction databases for this purpose, such as CASREACT® available from Chemical Abstract Services.
In addition to the classical preparations of products from corresponding educts, general chemical reactions with specific reactants, e.g. catalysts, can also be researched.
Furthermore, the individual reaction participants / compounds can also be searched in combination with corresponding database codes, so-called roles for starting materials or reaction products.