The present invention relates to compounds of the formula I in which substituents R.sup.2 and R.sup.3 are arranged in trans-configuration: ##STR00001## wherein: R.sup.1 is H or C1-C6 alkyl; C3-C7 cycloalkyl; R.sup.2 is phenyl, optionally substituted with 1 to 5 substituents independently selected from the group comprising OH, C1-C6-alkyl, halogen, nitro, cyano, SH, SR.sup.4, trihalo-C1-C6-alkyl, C1-C6-alkoxy and phenyl, wherein R.sup.4 is C1-C6 alkyl; R.sup.3 is phenyl substituted with OR.sup.5 wherein R.sup.5 has the formula (II), (III) or (IV) ##STR00002## wherein Y is chosen from NHR.sup.4, NR.sup.4.sub.2, NHCOR.sup.4, NHSO.sub.2R.sup.4, CONHR.sup.4, CONR.sup.4, CONR.sup.4.sub.2, COOH, COOR.sup.4, SO.sub.2R.sup.4, SOR.sup.4, SONHR.sup.4, SONR.sup.4.sub.2, a C3-C7 heterocyclic ring, saturated or unsaturated, containing one or two heteroatoms independently selected from the group consisting of O, S and N, optionally being substituted with 1 to 3 substituents independently selected from the group comprising H, OH, halogen, nitro, cyano, SH, SR.sup.4, trihalo-C1-C6-alkyl, C1-C6-alkyl and C1-C6-alkoxy, preferably NHR.sup.4, NR.sub.2.sup.4, or a nitrogen heterocycle, wherein R.sup.4 is as defined above, and the esters, ethers, and salts of the compounds of formula I, optionally along pharmaceutically acceptable excipients, a process for the preparation of the same, and a method of preventing and/or treating estrogen-related disease conditions in a subject using compounds of formula 1, or its salts, optionally along with pharmaceutically acceptable excipients.