The present invention relates to a compounds of formula I: ##STR00001## wherein A, B, D, E and F are defined herein; that are useful in treating central nervous system (CNS) diseases, disorders and conditions, such as but not limited to nicotine addiction, schizophrenia, depression, Alzheimer's disease, Parkinson's disease and ADHD. The present invention further comprises pharmaceutical compositions containing such compounds and methods of treatment comprising the use of such compounds.