A compound of formula: and salts thereof; wherein: X is O or S; Y is N or CR 2 R 1 is -H or -C 1-6 alkyl; R 2 is -H, -OH, -C 1-6 alkyl, -O-C 1-6 alkyl, -CN, -halo, -C(=O)NH 2, -C 1-6 haloalkyl, -O-C 1-6 alkyl-O-C 1-6 alkyl, -O-C 1-6 alkyl-OH, -O-C 1-6 alkyl-C(=O)NH 2, -O-C 1-6 alkyl-CN, -O-C 1-6 haloalkyl, -NH-C 1-6 alkyl, -N(C 1-6 alkyl) 2 or heteroaryl; R 3 is -C 1-6 alkyl, -C 1-6 alkyl-NH 2, or -C 1-6 alkyl-O-C 1-6 alkyl; R 4 is H, -C 1-6 alkyl, -C 1-6 haloalkyl, -C 1-6 alkyl-heteroaryl (wherein the heteroaryl group is optionally substituted by one, two or three C 1-6 alkyl groups), -C 1-6 alkyl-phenyl (wherein the phenyl group is optionally substituted by one, two or three substituents selected from the list consisting of halo, C 1-6 alkyl and -O-C 1-6 alkyl), -C 1-6 alkyl-heterocyclyl, -C 1-6 alkyl-C 3-6 cycloalkyl, -C 1-6 alkyl-OH, -C 1-6 alkyl-CN or -C 1-6 alkyl-O-C 1-6 alkyl; R 5 is -H, -C 1-6 alkyl, -O-C 1-6 alkyl, -OH, -halo, or -CN; or R 4 together with R 5 are -(R 4)-CH 2 CH 2 O-(R 5)-, -(R 4)-CH 2 CH 2 CH 2 O-(R 5)- or -(R 4)-CH(Me)CHzO-(Rs)-, wherein -(R 4)- and -(R 5)- denote the positions of attachment of the alkenyloxy chain to the respective ring atoms; R 6 is -H, -halo, -CN, -C 1-6 alkyl, -O-C 1-6 alkyl, or -OH; R 7 is -H, -halo, -CN, -C 1-6 alkyl, -O-C 1-6 alkyl, or -OH; R 8 is -H, -F or -C 1-6 alkyl; R 9 is -H or -C 1-6 alkyl; and NR 10 R 11 taken together form a 5-7 membered mono- or bi-cyclic saturated or unsaturated heterocycle containing one nitrogen atom, wherein the heterocycle is substituted by one, two or three substituents independently selected from the list consisting of -NH 2, -C 1-6 alkyl-NH 2, -NH-C 1-6 alkyl, -NHC(=NH)CH 2 Cl, -C 1-6 alkyl, - halo, -O-C 1-6 alkyl, -OH and -C NH 2; provided that the compound of formula is not or X is O or S; Y is N or CR 2 R 1 is -H or -C 1-6 alkyl; R 2 is -H, -OH, -C 1-6 alkyl, -O-C 1-6 alkyl, -CN, -halo, -C(=O)NH 2, -C 1-6 haloalkyl, -O-C 1-6 alkyl-O-C 1-6 alkyl, -O-C 1-6 alkyl-OH, -O-C 1-6 alkyl-C(=O)NH 2, -O-C 1-6 alkyl-CN, -O-C 1-6 haloalkyl, -NH-C 1-6 alkyl, -N(C 1-6 alkyl) 2 or heteroaryl; R 3 is -C 1-6 alkyl, -C 1-6 alkyl-NH 2, or -C 1-6 alkyl-O-C 1-6 alkyl; R 4 is H, -C 1-6 alkyl, -C 1-6 haloalkyl, -C 1-6 alkyl-heteroaryl (wherein the heteroaryl group is optionally substituted by one, two or three C 1-6 alkyl groups), -C 1-6 alkyl-phenyl (wherein the phenyl group is optionally substituted by one, two or three substituents selected from the list consisting of halo, C 1-6 alkyl and -O-C 1-6 alkyl), -C 1-6 alkyl-heterocyclyl, -C 1-6 alkyl-C 3-6 cycloalkyl, -C 1-6 alkyl-OH, -C 1-6 alkyl-CN or -C 1-6 alkyl-O-C 1-6 alkyl; R 5 is -H, -C 1-6 alkyl, -O-C 1-6 alkyl, -OH, -halo, or -CN; or R 4 together with R 5 are -(R 4)-CH 2 CH 2 O-(R 5)-, -(R 4)-CH 2 CH 2 CH 2 O-(R 5)- or -(R 4)-CH(Me)CHzO-(Rs)-, wherein -(R 4)- and -(R 5)- denote the positions of attachment of the alkenyloxy chain to the respective ring atoms; R 6 is -H, -halo, -CN, -C 1-6 alkyl, -O-C 1-6 alkyl, or -OH; R 7 is -H, -halo, -CN, -C 1-6 alkyl, -O-C 1-6 alkyl, or -OH; R 8 is -H, -F or -C 1-6 alkyl; R 9 is -H or -C 1-6 alkyl; and NR 10 R 11 taken together form a 5-7 membered mono- or bi-cyclic saturated or unsaturated heterocycle containing one nitrogen atom, wherein the heterocycle is substituted by one, two or three substituents independently selected from the list consisting of -NH 2, -C 1-6 alkyl-NH 2, -NH-C 1-6 alkyl, -NHC(=NH)CH 2 Cl, -C 1-6 alkyl, - halo, -O-C 1-6 alkyl, -OH and -C NH 2; provided that the compound of formula is not or