NOVEL OXA- OR AZASTEROID DERIVATIVE.

摘要

A compound represented by general formula (I), which has an aromatase inhibitory activity and is useful for preventing and treating diseases caused by hyperestrogenosis, such as mastocarcinoma, metrocarcinoma and prostatomegaly. In formula (I) A represents C=O, CH2, C=CH2 or C=CH-lower alkyl; B represents O, NH or N-lower alkyl; X is nil, or represents C=O or CH2; n is 2 or 3 when X is nil, or 1 or 2 when X represents C=O or CH2; and the broken line between the 1-position and the 2-position in the steroidal skeleton means an optional presence of a double bond therebetween.