A compound of formula wherein, R 1 is -C 1-3 alkyl or -C 1-3 haloalkyl; R 2 is selected from -NHR 4; R 3 is selected from -N(R 7, R 8), 5-12 membered heteroaryl, wherein the heteroaryl group is substituted with -X-R 10, and the heteroaryl group is optionally further substituted with one or more groups independently selected from R 9; R 4 is selected from -C 1-5 alkyl and 5-12 memebered heterocycloalkyl, which can be optionally substituted with one or more groups independently selected from R 5; R 5 is selected from -C 1-5 alkyl, -C 1-5 haloalkyl, -C 1-3 alkylene-O-C 1-3 alkyl, -C -C 1-3 alkyl, -C -H and -S 2 -R 6; R 6 is selected from -C 1-3 alkylene-N(C 1-3 alkyl) 2, -C 1-3 alkylene-NH 2 and 5-12 membered heterocycloalkyl, wherein the heterocycloalkyl can be optionally substituted with -C 1-3 alkyl; R 7, R 8 can be the same or different and are independently selected from -C 1-3 alkyl, -C 1-3 alkylene-C 6-10 aryl, -C 1-3 alkylene-(5-12 membered heteroaryl), wherein the aryl and the heteroaryl groups can be optionally substituted with one or more groups independently selected from halogen, -C 1-3 alkyl, -O-C 1-3 alkyl, -C 1-3 haloalkyl and -O-C 1-3 haloalkyl; R 9 is selected from-C 1-5 alkyl, halogen, -C 1-3 alkylene-O-C 1-3 alkyl, -C 1-5 alkylene-N(-C 1-5 alkyl, -C 1-5 alkyl), 5-12 memebered heterocycloalkyl,wherein the heterocycloalkyl group can be optionally substituted with -C 1-3 alkyl, or R 9 is selected from -C 6-10 aryl and 5-12 memebered heteroaryl, wherein the aryl and heteroaryl groups can be optionally and independently substituted with one or more groups selected from halogen, -C 1-3 alkyl, -O-C 1-3 alkyl, -C 1-3 haloalkyl, -O-C 1-3 haloalkyl, -N(C 1-5 alkyl, C 1-5 alkyl) and -NH-C 1-5 alkyl; X is -C 1-3 alkylene- or -O-; R 10 is-C 6-10 aryl or 5-12 membered heteroaryl, each of which groups can be optionally substituted with one or more groups selected from halogen, -C 1-3 alkyl, -O-C 1-3 alkyl, -C 1-3 haloalkyl, -O-C 1-3 haloalkyl; wherein the compounds of formula may be optionally be present in the form of salts. R 1 is -C 1-3 alkyl or -C 1-3 haloalkyl; R 2 is selected from -NHR 4; R 3 is selected from -N(R 7, R 8), 5-12 membered heteroaryl, wherein the heteroaryl group is substituted with -X-R 10, and the heteroaryl group is optionally further substituted with one or more groups independently selected from R 9; R 4 is selected from -C 1-5 alkyl and 5-12 memebered heterocycloalkyl, which can be optionally substituted with one or more groups independently selected from R 5; R 5 is selected from -C 1-5 alkyl, -C 1-5 haloalkyl, -C 1-3 alkylene-O-C 1-3 alkyl, -C -C 1-3 alkyl, -C -H and -S 2 -R 6; R 6 is selected from -C 1-3 alkylene-N(C 1-3 alkyl) 2, -C 1-3 alkylene-NH 2 and 5-12 membered heterocycloalkyl, wherein the heterocycloalkyl can be optionally substituted with -C 1-3 alkyl; R 7, R 8 can be the same or different and are independently selected from -C 1-3 alkyl, -C 1-3 alkylene-C 6-10 aryl, -C 1-3 alkylene-(5-12 membered heteroaryl), wherein the aryl and the heteroaryl groups can be optionally substituted with one or more groups independently selected from halogen, -C 1-3 alkyl, -O-C 1-3 alkyl, -C 1-3 haloalkyl and -O-C 1-3 haloalkyl; R 9 is selected from-C 1-5 alkyl, halogen, -C 1-3 alkylene-O-C 1-3 alkyl, -C 1-5 alkylene-N(-C 1-5 alkyl, -C 1-5 alkyl), 5-12 memebered heterocycloalkyl,wherein the heterocycloalkyl group can be optionally substituted with -C 1-3 alkyl, or R 9 is selected from -C 6-10 aryl and 5-12 memebered heteroaryl, wherein the aryl and heteroaryl groups can be optionally and independently substituted with one or more groups selected from halogen, -C 1-3 alkyl, -O-C 1-3 alkyl, -C 1-3 haloalkyl, -O-C 1-3 haloalkyl, -N(C 1-5 alkyl, C 1-5 alkyl) and -NH-C 1-5 alkyl; X is -C 1-3 alkylene- or -O-; R 10 is-C 6-10 aryl or 5-12 membered heteroaryl, each of which groups can be optionally substituted with one or more groups selected from halogen, -C 1-3 alkyl, -O-C 1-3 alkyl, -C 1-3 haloalkyl, -O-C 1-3 haloalkyl;