This invention relates provides novel substituted 1, 4-dioxa-8-azaspiro[4,5 ]decanc of general formula (1), wherein R1 is selected from phenethyl, 4, 6-dimethoxypyrimidin- 2-yl and (2-chloro-5-thiazolyl) methyl and R2 is selected from the group consisting of hydroxy, 4-bromo-2-chlorophenoxy, morpholin-4-yl, (2-chloro-5-thiazolyl) methyloxy, benzyloxy, phenylsulfanyl, benzotriazol- 1 -yl and 5-chloro-2-fluoroanilino. The present invention also relates to a process for the preparation of novel substituted l,4-dioxa-8- azaspiro[4,5]decanes of general formula (1). The novel substituted l,4-dioxa-8- azaspiro[4,5]decane of general formula ( 1) has fungicidal activity.