Microbiocidal heterobicyclic derivatives

1. A compound of formula I:

wherein

each of A 1 , A 2 , and A 3 independently represents a nitrogen atom or CR 7 ;

Y—X represents a radical selected from G1, G2, G3 and G4:

R 1 and R 2 are each independently selected from hydrogen, halogen, cyano, C 1 -C 6 alkyl, C 3 -C 7 cycloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, in which the alkyl, cycloalkyl, alkenyl and alkynyl groups may be optionally substituted with 1 to 3 substituents independently selected from halogen, C 1 -C 6 alkoxy, C 1 -C 6 alkylthio and phenoxy; or

R 1 and R 2 together with the carbon atom to which they are attached represent a C 3 -C 10 cycloalkyl group (which may be optionally substituted with 1 to 3 substituents independently selected from the group consisting of halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy and phenoxy);

R 3 and R 4 are each independently selected from hydrogen, halogen, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 3 -C 7 cycloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, in which the alkyl, alkoxy, cycloalkyl, alkenyl and alkynyl groups may be optionally substituted with 1 to 3 substituents independently selected from halogen, C 1 -C 6 alkoxy, C 1 -C 6 alkylthio and phenoxy; or

R 3 and R 4 together with the carbon atom to which they are attached represent C═O, C═CH 2 or C 3 -C 10 cycloalkyl (which may be optionally substituted with 1 to 3 substituents independently selected from the group consisting of a halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy and phenoxy);

R 5 is hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or hydroxyl;

R 6 is hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or hydroxyl;

each R 7 independently represents hydrogen, cyano, halogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, C 3 -C 7 cycloalkyl, C 2 -C 6 alkynyl, or hydroxyl;

each R 8 independently represents hydroxyl, halogen, cyano, amino, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 3 -C 7 cycloalkyl, C 2 -C 6 alkenyloxy, C 3 -C 6 alkynyloxy, C 1 -C 6 alkylthio, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, C 1 -C 6 alkylcarbonyl, NH(C 1 -C 6 alkyl), N(C 1 -C 6 alkyl) 2 , CO 2 H, CO 2 (C 1 -C 6 alkyl), C(O)N(C 1 -C 6 alkyl) 2 , C(O)NH(C 1 -C 6 alkyl), C(O)NH 2 , NH(C 1 -C 6 alkylcarbonyl), N(C 1 -C 6 alkylcarbonyl) 2 , aryl, heteroraryl, aryloxy or heteroraryloxy, in which the alkyl, cycloalkyl, alkenyl, alkynyl, alkoxy groups may be optionally substituted with 1 to 3 substituents independently selected from the group consisting of halogen, C 1 -C 6 alkoxy, hydroxyl, C 1 -C 6 alkylthio, C 1 -C 6 alkoxycarbonyl and phenoxy, and the aryl or heteroaryl groups may be optionally substituted with 1 to 5 substituents independently selected from the group consisting of halogen, C 1 -C 6 alkyl (which itself may be optionally substituted with 1 to 3 halogen atoms), C 1 -C 6 alkoxy, amino (which itself may be substituted with 1 or 2 groups independently selected from C 1 -C 6 alkyl, C 1 -C 6 alkylcarbonyl), nitro, cyano, hydroxyl, mercapto and C 1 -C 6 alkylthio; n is 0, 1, 2, 3 or 4;

R a is hydrogen, C 1 -C 6 alkylcarbonyl or C 1 -C 6 alkyl, which may be optionally substituted with 1 to 3 substituents independently selected from the group consisting of halogen, C 1 -C 6 alkoxy, C 1 -C 6 alkylthio and phenoxy; or a salt or N-oxide thereof.

2. A compound according to claim 1 wherein one or more of A 1 , A 2 , and A 3 represents CR 7 .

3. A compound according to claim 1 wherein each R 7 independently represents hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 2 -C 6 alkynyl, or hydroxyl.

4. A compound according to claim 1 , wherein Y—X is G1, G2 or G4.

5. A compound according to claim 1 , wherein R 1 and R 2 are each independently selected from hydrogen, cyano, C 1 -C 6 alkyl, C 3 -C 7 cycloalkyl, in which the alkyl and cycloalkyl groups may be optionally substituted with 1 to 3 substituents independently selected from halogen, C 1 -C 6 alkoxy, and C 1 -C 6 alkylthio; or R 1 and R 2 together with the carbon atom to which they are attached represent a C 3 -C 6 cycloalkyl group.

6. A compound according to claim 1 , wherein R 3 and R 4 are each independently selected from hydrogen, halogen, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, in which the alkyl and alkoxy groups may be optionally substituted with 1 to 3 substituents independently selected from halogen, C 1 -C 6 alkoxy, and C 1 -C 6 alkylthio; or R 3 and R 4 together with the carbon atom to which they are attached represent C═O, or C 3 -C 7 cycloalkyl, which may be optionally substituted with 1 to 3 substituents independently selected from halogen.

7. A compound according to claim 1 , wherein R 5 is hydrogen, halogen, or C 1 -C 6 alkyl.

8. A compound according to claim 1 , wherein R 6 is hydrogen, halogen, or C 1 -C 6 alkyl.

9. A compound according to claim 1 , wherein each R 8 independently represents hydroxyl, halogen, cyano, amino, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 3 -C 7 cycloalkyl, C 2 -C 6 alkenyloxy, C 3 -C 6 alkynyloxy, C 1 -C 6 alkylthio, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, C 1 -C 6 alkylcarbonyl, phenyl, heteroraryl (wherein heteroaryl is pyridyl, thiophenyl, thiazolyl, imidazolyl, or oxazolyl), phenoxy or heteroraryloxy (wherein heteroaryl is pyridyl, thiophenyl, thiazolyl, imidazolyl, or oxazolyl), in which the alkyl, cycloalkyl, alkenyl, alkynyl, alkoxy groups may be optionally substituted with 1 to 3 substituents independently selected from the group consisting of halogen, C 1 -C 6 alkoxy, hydroxyl, and the phenyl, phenoxy and heteroaryl groups may be optionally substituted with 1 to 5 substituents independently selected from the group consisting of halogen, C 1 -C 6 alkyl (which itself may be optionally substituted with 1 to 3 halogen atoms), or C 1 -C 6 alkoxy; n is 0, 1, 2, or 3.

10. A compound according to claim 1 , wherein R a is hydrogen or C 1 -C 6 alkyl when Y—X is G2.

11. A compound according to claim 1 wherein two or more of A 1 , A 2 , and A 3 represent CR 7 ; each R 7 independently represents hydrogen, halogen, C 1 -C 6 alkyl, or hydroxyl; Y—X is G1; R 1 and R 2 are each independently selected from C 1 -C 6 alkyl, in which the alkyl group may be optionally substituted with 1 to 3 substituents independently selected from halogen, and C 1 -C 6 alkoxy; or R 1 and R 2 together with the carbon atom to which they are attached represent a C 3 -C 6 cycloalkyl group; R 3 and R 4 are each independently selected from hydrogen, halogen, C 1 -C 6 alkyl; or R 3 and R 4 together with the carbon atom to which they are attached represent C═O, or cyclopropyl; R 5 is hydrogen, or halogen; R 6 is hydrogen, or C 1 -C 6 alkyl; each R 8 independently represents halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, phenyl, heteroraryl (wherein heteroaryl is pyridyl, thiophenyl or thiazolyl), phenoxy or heteroraryloxy (wherein heteroaryl is pyridyl, thiophenyl or thiazolyl), in which the alkyl and alkoxy groups may be optionally substituted with 1 to 3 substituents independently selected from the group consisting of halogen, and the phenyl, phenoxy and heteroaryl groups may be optionally substituted with 1 or 2 substituents independently selected from the group consisting of halogen, or C 1 -C 3 alkyl (which itself may be optionally substituted with 1 to 3 halogen atoms); n is 0, 1, or 2; and R a is hydrogen, or C 1 -C 2 alkyl; or a salt or N-oxide thereof.

12. A method of combating phytopathogenic diseases which comprises applying to a phytopathogen, to the locus of a phytopathogen, or to a plant susceptible to attack by a phytopathogen, or to propagation material thereof, a fungicidally effective amount of a compound of formula (I) as defined in claim 1 or a composition comprising a fungicidally effective amount of said compound.

13. A composition comprising a fungicidally effective amount of a compound of formula (I) as defined in claim 1 .

14. A composition according to claim 13 , wherein the composition further comprises at least one additional active ingredient and/or a diluent.