ch sub 3 ch sub 3 4 cl ch a 186 187114 ch sub 3 ch sub 3 ch sub 3 4 cl ch b 157 158__________________________________________________________________________ the azole derivatives useful in the practice of this invention can each be prepared by reacting an oxirane compound which is represented by the following formula ii str5 wherein x r 1 r 2 r 3 and n have the same meanings as defined above with a compound represented by the following formula iii str6 wherein m means a hydrogen atom or alkali metal and a has the same meaning as defined above in the presence of a diluent incidentally the oxirane compound represented by the formula ii can be obtained by reacting a cyclopentanone represented by formula iv below for example with dimethyloxosulfonium methylide or dimethylsulfonium methylide in the presence of a diluent for example in light of the process described in organic synthesis 49 78 1968 and journal of american chemical society 1353 1965 still more as a different method there is a method by which a methylenecyclopentane represented by the formula v is obtained from a cyclopentanone represented by the formula iv through the witting reaction refer to org syn 40 66 1966 and j org chem 28 1128 1963 and then the oxirane derivative represented by the formula ii can be obtained from the thus prepared compound by the epoxidation refer to org syn coll vol 4 552 1963 and org.