Described are compunds of formula (I), wherein W is O or S; X is NR8; Y is CR9R10—(CH2)n wherein R9 and R10 are independently of each other hydrogen or lower alkyl, and n is an integer of from and including 0 to and including 3; or Y is SO2; R1 is aryl; R2 is a mono- or bicyclic heteroaryl group comprising one or more ring nitrogen atoms with the exception that R2 cannot represent 2-phthalimidyl, and in case of Y═SO2 cannot represent 2,1,3-benzothiadiazol-4-yl; any of R3, R4, R5 and R6, independently of the other, is H or a substituent other than hydrogen; and R7 and R8, independently of each, other, are H or lower alkyl; or a N-oxide or a pharmaceutically acceptable salt thereof for the preparation of a pharmaceutical product for the treatment of a neoplastic disease which responds to an inhibition of the VEGF receptor tyrosine kinase activity. The compounds of formula (I) can be used for the treatment e.g. of a neoplastic disease, such as a tumor disease, of retinopathy and age-related macular degeneration.