The fact that Friedel-Crafts acylation in bromoalkylaromatics usually proceeds para to the bromine substituent has been considered to be an anomaly. The acetylation of the isomeric bromo-m-xylenes has been carried out, and product identification has confirmed this type of orientation. However, by a consideration of partial rate factors and competitive reactions, it is shown that these results may be
Disclosed is a triazole derivative(s) represented by the general formula (1) below or a pharmacologically acceptable salt(s) thereof. Also disclosed are a prodrug(s) of such a triazole derivative(s) and an HSP90 inhibitor(s) containing any one of them as an active constituent. (1) (In the formula, X represents a halogen atom, an optionally substituted alkyl group, an optionally substituted alkynyl group or the like; Y represents a mercapto group, a hydroxyl group, an optionally substituted sulfonyl group, an optionally substituted amino group or the like; and R represents an optionally substituted aryl or alkyl group or the like.)