FIELD: chemistry.SUBSTANCE: invention relates to compounds of formula (I), their racemic mixture, enantiomers, diastereomers and pharmaceutically acceptable salts, possessing properties of Syk inhibitor, pharmaceutical composition and medication based thereof, thereof application, methods of inhibiting and method of treatment with thereof application. In general formula (I) R1 represents hydrogen or C1-C6alkyl, R2 represents phenyl, benzo[d][1,3]dioxolyl, 2,3-dihydrobenzo[b][1,4]dioxinyl, or 5-10-membered heteroaryl, containing 1-2 heteroatoms, selected from N and O, which is optionally substituted with one or several groups, selected from halogen, -NR5R6, -OR7, -S(O)nR8, -C(O)R9, -CN, -C(O)NR5R6, -NR5C(O)R9, -NR5S(O)nR8, -S(O)nNR5R6, C1-C6alkyl, optionally substituted with one, two or three groups, selected from halogen, -OH, -OC1-C4alkyl, -NH2, -NH(C1-C4alkyl), -N(C1-C4alkyl)(C1-C4alkyl), -C(O)N(C1-C4alkyl)(C1-C4alkyl), or 5-8-membered heterocycle, containing 1-2 heteroatoms, selected from N, O, and S, optionally substituted with -SO2(C1-C4alkyl), C3-C6cycloalkyl, 5-8-membered heterocycle, containing 1-2 heteroatoms, selected from N, O and S, optionally substituted with one, two, or three groups, selected from halogen, -OH, C1-C4alkyl, -C1-C4alkyl-OH, ketogroup(oxo), -C(O)C1-C4alkyl, -C(O)C3-C6cycloalkyl, -C(O)C3-C6cycloalkyl-CN, -C(O)C3-C6cycloalkylhalogen, -C(O)NH2, -C(O)NH(C1-C4alkyl), -C(O)N(C1-C4alkyl)(C1-C4alkyl), -C(O)(C1-C4alkyl)-OH, -C(O)(C1-C4alkyl)-O(C1-C4alkyl), -C(O)C1-C4halogenalkyl, -C(O)(C1-C4alkyl)-CN, -C(O)(C1-C4alkyl)-C(O)NH2, -C(O)(C1-C4alkyl)C3-C6cycloalkyl, -C(O)(C1-C4alkyl)-oxetane, C(O)-furanyl, -C(O)-tetrahydrofuranyl, -C(O)(C1-C4alkyl)-SO2(C1-C4alkyl), -O(C1-C4alkyl)-OH, -SO2(C1-C4alkyl), -SO2NH(C1-C4alkyl), -SO2(C1-C4alkyl)(C1-C4alkyl), -SO2C3-C6cycloalkyl, -N(C1-C4alkyl)C(O)(C1-C4alkyl), and 5-6-membered heteroaryl, containing 1-2 nitrogen atoms, optionally substituted with C1-C4alkyl, R3 and R4 are independently selected from hydrogen
