The invention relates to a fungicidally active compound of formula (I): where Het is a 5- or 6-membered heterocyclic ring containing one to three heteroatoms, each independently selected from oxygen, nitrogen and sulphur, the ring being substituted by the groups R6, R7 and R8； R1 is hydrogen, C1-4 alkyl, C1-4 haloalkyl, C1-4 alkoxy, C1-4 haloalkoxy, CH2 C&equiv；CR9, CH2 CR10&boxH；CHR11, CH&boxH；C&boxH；CH2 or COR12； R2 and R3 are each, independently, hydrogen, halo, C1-4 alkyl, C1-4 alkoxy, C1-4 haloalkyl or C1-4 haloalkoxy； R4 and R5 are each independently selected from halo, cyano and nitro； or one of R4 and R5 is hydrogen and the other is selected from halo, cyano and nitro； R6, R7 and R8 are each, independently, hydrogen, halo, cyano, nitro, C1-4 alkyl, C1-4 haloalkyl, C1-4 alkoxy(C1-4)alkyl, C1-4 haloalkoxy(C1-4)alkyl or C1-4 haloalkoxy, provided that at least one of R6, R7 and R8 is not hydrogen； R9, R10 and R11 are each, independently, hydrogen, halo, C1-4 alkyl, C1-4 haloalkyl or C1-4 alkoxy(C1-4)alkyl； and R12 is hydrogen, C1-6 alkyl, C1-6 haloalkyl, C1-4 alkoxy(C1-4)alkyl, C1-4 alkylthio(C1-4)-alkyl, C1-4 alkoxy or aryl； to the preparation of these compounds, to novel intermediates used in the preparation of these compounds, to agrochemical compositions which comprise at least one of the novel compounds as active ingredient, to the preparation of the compositions mentioned and to the use of the active ingredients or compositions in agriculture or horticulture for controlling or preventing infestation of plants by phytopathogenic microorganisms, preferably fungi.本發明係有關一種式(I)之殺真菌活性化合物：；(I)；其中Het為包含一至三個各自獨立地選自氧、氮和硫的雜原子之5－或6－員雜環，該環經基團R6、R7和R8取代；R1為氫、C1－4烷基、C1－4鹵烷基、C1－4烷氧基、C1－4鹵烷氧基、CH2C≡C－R9、CH2CR10＝CHR11、CH＝C＝CH2或COR12；R2和R3各自獨立地為氫、鹵基、C1－4烷基、C1－4烷氧基、C1－4鹵烷基或C1－4鹵烷氧基；R4和R5各自獨立地選自鹵基、氰基和硝基；或R4和R5之一為氫和另一個選自鹵基、氰基和硝基；R6、R7和R8各自獨立地為氫、鹵基、氰基、硝基、C1－4烷基、C1－4鹵烷基、C1－4烷氧基(C1－4)烷基、C1－4鹵烷氧基(C1－4)烷基或C1－4鹵烷氧基，其條件為R6、R7和R8之至少一個不為氫；R9、R10和R11各自獨立地為氫、鹵基、C1－4烷基、C1－4鹵烷基或C1－4烷氧基(C1－4)
