US Patent 7446129 Benzylated PDE4 inhibitors

The present invention is directed to a method for reducing the emetogenic effects of PDE inhibitors, and more particularly is directed to compounds having PDE4 inhibition activity with little or no emetogenic side-effects, and chemical methods including benzylation for preparing such compounds. A benzyl group may be attached to either a carbon or nitrogen atom of a PDE4 inhibitor. Suitable benzylation chemistry is to extract a hydrogen from a PDE4 inhibitor, preferably with a base, and then react the resulting nucleophilic PDE4 inhibitor with a benzylating agent, e.g., benzyl bromide or a derivative thereof.