Physiologically active substance TAN-931, its derivatives, their production and use

摘要

A novel compound of the formula (I): <IMAGE> (I) wherein R1 is esterified carboxyl; R2, R3 and R4 are the same or different and are hydrogen or alkyl; A is formyl, hydroxyiminomethyl or carboxyl; and X is hydrogen or halogen, or a salt thereof, which is useful as an aromatase inhibitor or an intermediate of its production. Processes for producing the compound of the formula (I) and an aromatase inhibitor containing as an active component the compound of the formula (I) wherein A is formyl and X is hydrogen or, a salt thereof as well as Penicillium funiculosum capable for producing the compound (I) wherein R1 is carboxyl, R2, R3 and R4 are hydrogen and X is formyl are also disclosed.