| abstract |
A condensed pyrimidine derivative of the formula (I): ##STR1## wherein the ring A stands for an optionally substituted 5-membered ring; B stands for an optionally substituted divalent 5- or 6-membered homo- or hetero-cyclic group; X stands for, among others, amino group; Y stands for, among others, hydrogen atom, halogen atom or amino group; Z stands for a divalent aliphatic group having five or less atoms forming straight chain, optionally having nitrogen, whose chain portion may optionally have a hetero-atom; W stands for, among others, --NH--CO-- or --CO--NH--; R 1 stands for an optionally substituted cyclic or chain-like group; COOR 2 stands for an optionally esterified carboxyl group; and p denotes an integer of 1 to 4, provided that when --W--R 1 denotes a moiety represented by the formula: ##STR2## wherein COOR 16 and COOR 17 are, independently, an optionally esterified carboxyl group and n denotes an integer of 1 to 5, p denotes 1, 3 or 4, or a salt thereof, exhibiting highly specific toxicities to various tumor cells and excellent therapeutic effects on methotrexate-resistant tumor cells as well. |