Patent ID: 7432255

Claim:
A compound of formula I: or a pharmaceutically acceptable salt thereof, wherein: R 1 is lower alkyl or cycloalkyl; R 2 is hydrogen or halogen; R 3 is hydrogen or lower alkyl; and R 4 is —(CR 5 R 6 ) m —NR 7 R 8 or —(CR 9 R 10 ) n -heterocyclyl, wherein: (a) R 5 is hydrogen or lower alkyl; (b) R 6 is hydrogen or lower alkyl; (c) R 7 and R 8 independently from each other are selected from the group consisting of: (1) lower alkyl, (2) phenyl optionally substituted by lower alkyl, (3) lower phenylalkyl, and (4) lower hydroxyalkyl; or alternatively R 7 and R 8 together with the nitrogen atom to which they are attached form a 3-, 4-, 5-, 6- or 7-membered saturated heterocyclic ring optionally containing a further heteroatom of oxygen or sulfur, said heterocyclic ring being optionally substituted by lower alkyl; (d) R 9 is hydrogen or lower alkyl; (e) R 10 is hydrogen or lower alkyl; (f) said heterocyclyl of the —(CR 9 R 10 ) n -heterocyclyl is a N-heterocyclic ring selected from the group consisting of pyrrolidine, pyrrolidin-2-one, piperidine and morpholine, wherein the nitrogen atom of the N-heterocyclic ring is substituted by a substituent selected from the group consisting of: (1) lower alkyl, (2) cycloalkyl, (3) lower phenylalkyl, (4) lower cyanoalkyl, (5) lower halogenalkyl, (6) lower alkoxyalkyl, (7) phenyl optionally substituted by one to three substituents selected from the group consisting of lower alkyl, lower alkoxy, lower halogenalkyl and halogen, and (8) —COOR 11 ; wherein R 11 is lower alkyl; (g) m is 2 or 3, and (h) n is 0, 1, 2 or 3.