Microbiocidal oxadiazole derivatives

1. A compound of formula (I):

wherein

R 1 and R 2 are independently selected from hydrogen, chloro, fluoro, methyl, methoxy and trifluoromethyl; and

R 3 and R 4 are independently selected from hydrogen and halogen;

wherein at least two of R 1 , R 2 , R 3 and R 4 are hydrogen;

R 5 and R 6 are independently selected from hydrogen and C 1-4 alkyl;

R 7 is C 1-4 alkyl or C 1-4 alkoxy; and

R 8 is hydrogen, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, cyanoC 1-6 alkyl, C 1-6 haloalkyl, C 1-6 haloalkenyl, hydroxyC 1-6 alkyl, C 1-4 alkoxyC 1-6 alkyl, C 1-4 haloalkoxyC 1-6 alkyl, C 1-4 alkoxyC 1-4 alkoxyC 1-6 alkyl, C 2-4 alkynyloxyC 1-6 alkyl, aminoC 1-6 alkyl, N—C 1-4 alkylaminoC 1-6 alkyl, N,N-diC 1-4 alkylaminoC 1-6 alkyl, C 1-6 alkylcarbonylC 1-6 alkyl, C 1-6 alkylcarbonylC 2-6 alkenyl, C 1-6 alkoxycarbonylC 1-6 alkyl, C 1-6 alkylcarbonyloxyC 1-6 alkyl, N—C 1-4 alkylaminocarbonylC 1-6 alkyl, N,N-diC 1-4 alkylaminocarbonylC 1-6 alkyl, C 1-6 alkylsulfanylC 1-6 alkyl, C 1-6 alkylsulfonylC 1-6 alkyl, C 1-6 alkylsulfonylaminoC 1-6 alkyl, C 1-6 alkylsulfonylaminoC 2-6 alkynyl, or C 2-6 alkynyloxycarbonylaminoC 1-6 alkyl; or

R 8 is C 3-8 cycloalkylC 0-6 alkyl, wherein the cycloalkyl moiety is optionally partially unsaturated, phenylC 0-6 alkyl, phenylC 2-6 alkenyl, naphthylC 0-6 alkyl, heteroarylC 0-6 alkyl wherein the heteroaryl moiety is a 5- or 6-membered monocyclic aromatic ring which comprises 1, 2, 3 or 4 heteroatoms individually selected from N, O and S, heterodiarylC 0-6 alkyl wherein the heterodiaryl moiety is a 9- or 10-membered bicyclic aromatic system which comprises 1, 2, 3 or 4 heteroatoms individually selected from N, O and S, heterocyclylC 0-6 alkyl wherein the heterocyclyl moiety is a 4-to 6-membered non-aromatic ring which comprises 1, 2 or 3 heteroatoms individually selected from N, O and S, or C 3-6 cycloalkylcarbonylaminoC 1-6 alkyl,

wherein for R 8 , any of C 3-8 cycloalkylC 0-6 alkyl, phenylC 0-6 alkyl, phenylC 2-6 alkenyl, naphthylC 0-6 alkyl, heteroarylC 0-6 alkyl, heterodiarylC 0-6 alkyl, heterocyclylC 0-6 alkyl and C 3-6 cycloalkylcarbonylaminoC 1-6 alkyl moieties are optionally substituted by 1, 2 or 3 substituents, which may be the same or different, selected from R 9 ; wherein

R 9 represents cyano, halogen, hydroxy, C 1-4 alkyl, C 2-4 alkenyl, C 2-4 alkynyl, C 1-4 haloalkyl, C 2-4 haloalkenyl, C 1-4 alkoxy, C 1-4 haloalkoxy, C 3-4 alkynyloxy, N—C 1-4 alkylamino, N,N-diC 1-4 alkylamino, C 1-4 alkylcarbonyl, C 1-4 alkoxycarbonyl, carbonylamino, N—C 1-4 alkylaminocarbonyl, N,N-diC 1-4 alkylaminocarbonyl or C 1-4 alkoxycarbonylamino, and wherein when R 8 is substituted C 3-8 cycloalkylC 0-6 alkyl or heterocyclylC 0-6 alkyl, R 9 may also represent oxo on the C 3-8 cycloalkyl or heterocyclyl moiety; or

wherein for R 8 , any of C 3-8 cycloalkylC 0-6 alkyl, phenylC 0-6 alkyl, phenylC 2-6 alkenyl, naphthylC 0-6 alkyl, heteroarylC 0-6 alkyl, heterodiarylC 0-6 alkyl, heterocyclylC 0-6 alkyl and C 3-6 cycloalkylcarbonylaminoC 1-6 alkyl moieties are optionally substituted by 1 substituent selected from R 10 ; wherein

R 10 represents C 3-8 cycloalkylC 0-2 alkyl, phenylC 0-2 alkyl, heteroarylC 0-2 alkyl wherein the heteroaryl moiety is a 5- or 6-membered monocyclic aromatic ring which comprises 1, 2, 3 or 4 heteroatoms individually selected from N, O and S, heterocyclylC 0-6 alkyl wherein the heterocyclyl moiety is a 4- to 6-membered non-aromatic ring which comprises 1, 2 or 3 heteroatoms individually selected from N, O and S, and wherein any of said cycloalkyl, phenyl, heteroaryl and heterocyclyl moieties are optionally substituted by 1, 2 or 3 substituents, which may be the same or different, selected from R 11 ; wherein

R 11 represents hydrogen, cyano, fluoro, chloro, bromo, methyl, trifluoromethyl, methoxy and ethoxy; or

a salt or an N-oxide thereof.

2. The compound according to claim 1 , wherein R 8 represents hydrogen, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, cyanoC 1-6 alkyl, C 1-6 haloalkyl, C 1-6 haloalkenyl, hydroxyC 1-6 alkyl, C 1-4 alkoxyC 1-6 alkyl, C 1-4 haloalkoxyC 1-6 alkyl, C 1-4 alkoxyC 1-4 alkoxyC 1-6 alkyl, C 2-4 alkynyloxyC 1-6 alkyl, C 1-6 alkylcarbonylC 2-6 alkenyl, C 1-6 alkylcarbonyloxyC 1-6 alkyl, C 1-6 alkylsulfonylaminoC 2-6 alkynyl, C 2-6 alkynyloxycarbonylaminoC 1-6 alkyl; or

C 3-8 cycloalkylC 0-2 alkyl, wherein the cycloalkyl moiety is optionally partially unsaturated, phenylC 0-2 alkyl, heteroarylC 0-2 alkyl wherein the heteroaryl moiety is a 5- or 6-membered monocyclic aromatic ring which comprises 1, 2, 3 or 4 heteroatoms individually selected from N, O and S, or heterocyclylC 0-2 alkyl wherein the heterocyclyl moiety is a 4- to 6-membered non-aromatic ring which comprises 1, 2 or 3 heteroatoms individually selected from N, O and S; wherein any of said C 3-8 cycloalkylC 0-2 alkyl, phenylC 0-2 alkyl, heteroarylC 0-2 alkyl and heterocyclylC 0-2 alkyl moieties are optionally substituted by 1, 2 or 3 substituents, which may be the same or different, selected from R 9 ; and

R 9 represents cyano, halogen, hydroxy, C 1-4 alkyl, C 1-4 haloalkyl, C 1-4 alkoxy, C 2-4 haloalkenyl, C 3-4 alkynyloxy, C 1-4 alkylcarbonyl and C 1-4 alkoxycarbonyl.

3. The compound according to claim 1 , wherein R 8 represents C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 1-6 fluoroalkyl, C 1-6 chloroalkyl, C 1-4 alkoxyC 1-6 alkyl, C 1-4 alkoxyC 1-4 alkoxyC 1-6 alkyl, C 1-6 alkylcarbonylC 2-6 alkenyl, C 1-6 alkylcarbonyloxyC 1-6 alkyl, C 1-6 alkylsulfonylaminoC 2-6 alkynyl or C 2-6 alkynyloxycarbonylaminoC 1-6 alkyl.

4. The compound according to claim 1 , wherein R 8 represents C 3-8 cycloalkylC 0-6 alkyl, phenylC 0-6 alkyl, or heterocyclylC 0-6 alkyl, wherein any of said cycloalkyl, phenyl, and heterocyclyl moieties are optionally substituted by 1, 2 or 3 substituents which may be the same or different, selected from R 9 , wherein R 9 is cyano, halogen, hydroxy, C 1-4 alkyl, C 1-4 haloalkyl, C 2-4 haloalkenyl, C 3-4 alkynyloxy, C 1-4 alkylcarbonyl, C 1-4 alkoxycarbonyl; or wherein any of said cycloalkyl, phenyl, and heterocyclyl moieties are optionally substituted by 1 substituent selected from R 10 which is a phenyl.

5. The compound according to claim 4 , wherein R 8 represents C 3-6 cycloalkylC 0-1 alkyl, phenylC 0-1 alkyl or heterocyclylC 0-1 alkyl, wherein any of said cycloalkyl, phenyl, and heterocyclyl moieties are optionally substituted by 1, 2 or 3 substituents which may be the same or different, selected from R 9 , wherein R 9 is cyano, fluoro, chloro, hydroxy, methyl, ethyl, trifluoromethyl, 2,2-dichloroethenyl, propynyloxy, acetyl, methoxycarbonyl; or wherein any of said cycloalkyl, phenyl, and heterocyclyl moieties are optionally substituted by 1 substituent selected from R 10 which is a phenyl.

6. The compound according to claim 1 , wherein R 1 and R 2 are independently selected from hydrogen and fluorine.

7. The compound according to claim 1 , wherein R 3 and R 4 are independently selected from hydrogen and fluorine.

8. The compound according to claim 1 , wherein R 5 and R 6 are hydrogen, or R 5 is hydrogen and R 6 is methyl.

9. The compound according to claim 1 , wherein R 7 represents methoxy, propoxy or sec-butyl.

10. The compound according to claim 1 , said compound being selected from:

11. An agrochemical composition comprising a fungicidally effective amount of a compound of formula (I) according to claim 1 .

12. A composition according to claim 11 , further comprising at least one additional active ingredient and/or an agrochemically-acceptable diluent or carrier.

13. A method of controlling or preventing infestation of useful plants by phytopathogenic microorganisms, wherein a fungicidally effective amount of a compound of formula (I) according to claim 1 , or a composition comprising this compound as active ingredient, is applied to the plants, to parts thereof or the locus thereof.