Substituted quinolines as antitumor agents

A compound of Formula (Ia),

• or a pharmaceutically acceptable salt thereof
• wherein:
• n is 0 or 1;
• Y is selected from —NH— or —NR7— where R7 is alkyl of 1–6 carbon atoms;
• R5 is cyano, fluoro, chloro or bromo;
• R6 is a group —R8—X—R9 where
• R8 is a phenyl ring;
• wherein the phenyl ring may be optionally further substituted with one or more groups selected from halogen, alkyl of 1–6 carbon atoms, alkenyl of 2–6 carbon atoms, alkynyl of 2–6 carbon atoms, azido, hydroxyalkyl of 1–6 carbon atoms, halomethyl, alkoxymethyl of 2–7 carbon atoms, alkanoyloxymethyl of 2–7 carbon atoms, alkoxy of 1–6 carbon atoms, alkylthio of 1–6 carbon atoms, hydroxy, trifluoromethyl, cyano, nitro, carboxy, carboalkoxy of 2–7 carbon atoms, carboalkyl of 2–7 carbon atoms, phenoxy and phenyl;
• and where
• X is selected from —NH—, —S—, CH2 or —NR7′ — where R7′ is alkyl of 1–6 carbon atoms, and
• R9 is a group (CH2)mR10 where m is 0 or an integer of from 1–3 and R10 is an optionally substituted aryl or optionally substituted cycloalkyl ring of up to 10 carbon atoms, or R10 is a optionally substituted heterocyclic ring or an N-oxide of any nitrogen containing ring;
• or where
• X is —O—, and
• R9 is a group (CH2)mR10 where m is 0 or an integer of from 1–3 and R10 is aryl, a cycloalkyl ring of up to 10 carbon atoms, a heterocyclic ring or an N-oxide of any nitrogen containing ring wherein each R10 group bears at least one substituent group;
• R1, R2, R4 are independently selected from hydrogen, hydroxy, halogeno, cyano, nitro, trifluoromethyl, C1-3alkyl, —NR11R12— (wherein R11 and R12, which may be the same or different each represents hydrogen, or C1-3alkyl), or a group R13—X1—(CH2)x wherein x is 0 or an integer of from 1 to 3, X1 represents —O—, —S—, —SO—, —SO2—, or —NR18—(wherein R18 is hydrogen, C1-3alkyl or C1-3alkoxyC2-3alkyl)), and R13 is an optionally substituted hydrocarbyl;
• and
• R3 is a group of formula —X1—Rx′—X1a (C3-6cycloalkyl) where X1 is as defined above, R1a is as defined for X1 above and Rx′is an alkylene.