Abstract: New 4(5)-imidazole derivatives of formula (Ia) and (Ib) wherein one of R.sub.1 and R.sub.2 is CN and the other one is H, CH.sub.3, OCH.sub.3, NO.sub.2, NH.sub.2, CN, CF.sub.3, CHF.sub.2, CH.sub.2 F or halogen; R' is H or (II) where R.sub.3 is H, CH.sub.3 or halogen; R.sub.4 is H and R.sub.5 is H or R.sub.4 and R.sub.5 together form a bond, n is 1 or 2 and y is 0 to 2, their stereoisomers and their non-toxic pharmaceutically acceptable acid addition salts exhibit selective aromatase inhibiting properties, compared with their desmolase inhibiting properties. The compounds of the invention are valuable in the treatment of estrogen dependent diseases, e.g. breast cancer or benign prostatic hyperplasia (BPH).

Abstract: Novel 4(5)-imidazole derivatives of specified formula and their non-toxic salts possess selective aromatase inhibiting properties, which are valuable in the treatment of estrogen dependent diseases e.g. breast cancer.

Abstract: Imidazole derivatives of the formula: ##STR1## wherein R.sub.1, R.sub.2, R'.sub.1 and R'.sub.2 which can be the same or different, are H, CH.sub.3, C.sub.2 H.sub.5, OCH.sub.3, OH, CH.sub.2 OH, NH.sub.2 or halogen; R' if H or ##STR2## where R.sub.3 is H, CH.sub.3, or halogen; R.sub.4 is H and R.sub.5 is H or OH and R.sub.6 is H or OH or one of R.sub.5 and R.sub.6 is H and the other, together with R.sub.4, forms a bond and X and Y, which can be the same or different, are a bond, a straight C.sub.1-2 -alkyl or the corresponding alkenyl, and pharmaceutically acceptable salts thereof exhibit valuable pharmacological properties, especially aromatase inhibiting effects and are useful in the treatment of estrogen dependent diseases, e.g. breast cancer. Anti-mycotic and antifungal properties have also been found.