Compounds of formula: and pharmaceutically acceptable salts, esters and solvates thereof, where variables are defined in the specification, useful generally as inhibitors of protein kinases and particularly useful for inhibition of GSK-3. Pharmaceutically compositions and medicaments containing a compound of the invention are provided. The invention provides methods of treatment of protein kinase-related disease, disorders or conditions. The invention provides methods of treatment of GSK-3-related diseases, disorders or conditions. More specifically, methods of treatment of bipolar disorder, including mania, schizophrenia, stroke, epilepsy, motor neuron disease, cranial or spinal trauma, neurodegenerative disorders, including multiple sclerosis (MS), Alzheimer's disease, Fragile X syndrome, autism, Huntington's disease, Parkinson's disease, amylotrophic lateral sclerosis (ALS), AIDS-associated dementia, diabetes, particularly type II diabetes, cardiomycete hypertrophy, reperfusion/ischemia, cancer, particularly colorectal cancer, pancreatic cancer, allergies and/or asthma and hair loss or baldness.