Compounds of the following structure are provided, wherein n, R.sub.1-R.sub.3 and R.sub.6-R.sub.9 are defined below, as are methods of preparing and using these compounds for contraception; treating or preventing fibroids, uterine leiomyomata, endometriosis, dysfunctional bleeding, polycystic ovary syndrome, and hormone-dependent carcinomas; providing hormone replacement therapy; stimulating food intake; synchronizing estrus; and treating cycle-related symptoms.