Novel heteroatom containing tetracyclic derivatives as selective estrogen receptor modulators

Disclosed are heteroatom containing tetracyclic derivatives. The compounds are useful in the treatment and/or prevention of disorders associated with the depletion of estrogen such as hot flashes, vaginal dryness, osteopenia and osteoporosis hormone sensitive cancers and hyperplasia of the breast, endometrium, cervix and prostate endometriosis, uterine fibroids, osteoarthritis and as contraceptive agents, alone or in combination with a progestogen or progestogen antagonist.