Heteroatom containing tetracyclic derivatives as selective estrogen receptor modulators

The present invention is directed to novel heteroatom containing tetracyclic derivatives, pharmaceutical compositions containing them, their use in the treatment and/or prevention of disorders mediated by one or more estrogen receptors and processes for their preparation. The compounds of the invention 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.