1,3,4-oxadiazoles

A 1,3,4-oxadiazole of the formula:

• ##STR122## wherein R.sup.1 is an alkyl group, a phenyl group optionally having a lower alkoxy group, a hydroxy group, a lower alkyl group, optionally having a halogen substituent, a halogen atom or an anilino group, optionally substituted on the phenyl ring with 1-3 lower alkyl groups optionally having a halogen substituent or a halogen atom, an adamantyl group, a naphthyl group, a phenyl(lower)alkyl group, optionally having a phenoxy group as a substituent on the phenyl ring, or an unsaturated 5-membered to 11-membered heteromonocyclic or heterobicyclic group having 1-4 heteroatoms selected from the group consisting of a nitrogen, an oxygen and a sulfur atom, said heterocyclic group being optionally substituted with a phenyl group, a phenoxy group or a lower alkyl group;
• R.sup.2 is a phenyl group, optionally having 1-3 lower alkyl groups or hydroxyl groups, a phenyl(lower)alkyl group, ##STR123## wherein R.sup.3 is a hydrogen atom, or a lower alkoxy group, a quinolyl group or a lower alkyl group substituted by an unsaturated 5-membered to 11-membered heteromonocyclic or heterobicyclic group having 1-4 heteroatoms selected from the group consisting of a nitrogen, an oxygen and a sulfur atom, said heterocyclic group being optionally substituted with a phenyl group having optionally a lower alkyl substituent on the phenyl ring, a phenyl(lower)alkyl group, a lower alkoxy group, an oxo group, a lower alkyl group or a phenoxy group and n is 0 or 1;
• with the provisos that R.sup.1 is not a 4H-pyranyl group or a 1,4-dihydropyridyl group;
• when R.sup.1 is a lower alkyl group or phenyl group, R.sup.2 is not a pyrazyl-substituted lower alkyl group having a lower alkyl group, a lower alkoxy group or an oxo group;
• and R.sup.2 is not a 1,1,3-trioxo-1,2-benzisothiazolylmethyl group;
• or a salt thereof.