Fungicidal imidazole and 1,2,4-triazole derivatives

Compounds of formula (I): and stereoisomers thereof, wherein R represents phenyl, biphenyl, naphthyl or alkyl, all optionally substituted; R , R , R and R each represents a hydrogen atom or an alkyl group containing from 1 to 4 carbon atoms; R represents a hydrogen atom, an alkyl or acyl group, or a group of formula (II): R represents an alkyl, cycloalkyl, aryl, aralkyl or heteroaryl group; or R and R , together with the nitrogen atom to which they are attached, represent an optionally substituted ring which may contain hetero atoms; R and R each represent a hydrogen atom or an alkyl group, or together with the nitrogen atom to which they are attached form a ring; X is -N= or =CH-; Y is oxygen or sulphur; and n is 0, 1 or 2; and ether and ester derivatives (of the alcohol function) and acid addition salts and metal complexes thereof have fungicidal activity.