The invention provides compounds of formula (I)
the stereoisomers and prodrugs thereof, and the pharmaceutically acceptable salts of the compounds, stereoisomers, and prodrugs, wherein R
1
, R
2
, and R
3
are as defined herein; pharmaceutical compositions thereof; and use thereof in the treatment of, inter alia, conditions, diseases, and symptoms such as diabetes, dementia, Alzheimer's Disease, stroke, schizophrenia, depression, hair loss, and cancer.