Triazole derivatives

A compound of the formula (I): ##STR1##

wherein R¹ is lower alkyl which is optionally substituted with

• halogen, cyano,
• N,N-di(lower)alkylcarbamoyl,
• phenyl optionally substituted with halogen, or heterocyclic group,
• cyclo(lower)alkyl,
• lower alkynyl, or
• N,N-di(lower)alkylcarbamoyl;
• R² is lower alkyl, lower alkoxy, cyano, or 1H-pyrrol-1-yl;
• R³ is lower alkyl, lower alkoxy, or cyano;
• X is O, S, SO or SO₂;
• Y and Z are each CH or N; and
• m is 0 or 1;

  or salts thereof, which are useful as a medicament.