Yet another free chemistry database comes in the form of Sigma-Aldrich's Reaction Search. Draw your reactant and product, and let the database do the rest. Both exact and substructure matching can be used. Search results contain bibliographical references to the primary literature. And if a result's product is available from Aldrich, you'll get a link to the product summary page from where you can purchase it.
Like Sigma-Aldrich's ChemBlogs, Reaction Search matches the needs of a for-profit company to attract customers with the needs of chemists for unrestricted free access to research tools. Could this be the shape of things to come?
The parallels to Aldrich's Handbook are striking. Few bench chemists today regularly use a CRC Handbook, yet nearly all of them have a copy of the Aldrich catalog at their desks. Aldrich seems to get this simple idea like no other company. And they're quietly transferring this understanding to the Web.