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.