The present invention provides a compound of formula I: ##STR00001## or a pharmaceutically acceptable salt or mixtures thereof. These compounds are inhibitors of protein kinases, particularly inhibitors of GSK mammalian protein kinase, and more particularly inhibitors of GSK-3 mammalian protein kinase. The invention also provides pharmaceutically acceptable compositions comprising the compounds of the invention and methods of utilizing those compounds and compositions in the treatment of various protein kinase mediated disorders.