The present invention discloses and claims compounds of formula (I) and formula (II) ##STR00001## as inhibitors of human casein kinase I.epsilon., and methods of using the compounds of formula (I) and formula (II) for treating central nervous system diseases and disorders including mood disorders and sleep disorders. The R-group substituents are defined herein and pharmaceutical compositions comprising compounds of formula (I) or formula (II) are also disclosed and claimed.