Compounds of structural formula (I) are disclosed as useful for modulating the androgen receptor (AR) in a tissue selective manner in a patient in need of such modulation, and in particular for antagonizing AR in the prostate of a male patient or in the uterus of a female patient and agonizing AR in bone and/or muscle tissue. These compounds are useful in the treating conditions caused by androgen deficiency or which can be ameliorated by androgen administration, including: osteoporosis, periodontal disease, bone fracture, bone damage following bone reconstructive surgery, sarcopenia, frailty, aging skin, male hypogonadism, female sexual dysfunction, post-menopausal symptoms in women, atherosclerosis, hypercholesterolemia, hyperlipidemia, aplastic anemia and other hematopoietic disorders, pancreatic cancer, renal cancer, prostate cancer, arthritis and joint repair, alone or in combination with other active agents. In addition, these compounds are useful as pharmaceutical composition ingredients alone and in combination with other active agents.