Patent ID: 7501425

Claim:
A compound of formula I or a pharmaceutically acceptable salt thereof, wherein: R 1 and R 2 are independently selected from the group consisting of H, (CH 2 ) n Ar, COR 4 , (CH 2 ) n heteroaryl, (CH 2 ) n heterocyclyl, C 1 -C 10 alkyl, C 3 -C 10 cycloalkyl, C 2 -C 10 alkenyl, and C 2 -C 10 alkynyl, wherein n is 0, 1, 2, or 3, and the (CH 2 ) n Ar, (CH 2 ) n heteroaryl, alkyl, cycloalkyl, alkenyl, and alkynyl groups are optionally substituted by up to 5 groups selected from NR 4 R 5 , N + (O)R 4 R 5 , N + R 4 R 5 R 6 Y − , alkyl, phenyl, substituted phenyl, (CH 2 ) n heteroaryl, hydroxy, alkoxy, phenoxy, thiol, thioalkyl, halo, COR 4 CO 2 R 4 , CONR 4 R 5 , SO 2 NR 4 R 5 , SO 3 R 4 , PO 3 R 4 , aldehyde, nitrile, nitro, heteroaryloxy, T(CH 2 ) m QR 4 , C(O)T(CH 2 ) m QR 4 , NHC(O)T(CH 2 ) m QR 4 , T(CH 2 ) m C(O)NR 4 NR 5 , or T(CH 2 ) m CO 2 R 4 wherein each m is independently 1-6, T is O, S, NR 4 , N + (O)R 4 , N + R 4 R 6 Y − , or CR 4 R 5 , and Q is O, S, NR 5 , N + (O)R 5 , or N + R 5 R 6 Y − ; R 4 and R 5 are each independently selected from the group consisting of hydrogen, C 1 -C 6 alkyl, substituted alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, N(C 1 -C 6 alkyl) 1 or 2 , (CH 2 ) n Ar, C 3 -C 10 cycloalkyl, heterocyclyl, and heteroaryl, or R 4 and R 5 together with the nitrogen to which they are attached optionally form a ring having 3 to 7 carbon atoms and said ring optionally contains 1, 2, or 3 heteroatoms selected from the group consisting of nitrogen, substituted nitrogen, oxygen, and sulfur; when R 4 and R 5 together with the nitrogen to which they are attached form a ring, the said ring is optionally substituted by 1 to 3 groups selected from OH, OR 4 , NR 4 R 5 , (CH 2 ) m OR 4 , CH 2 ) m NR 4 R 5 , T—(CH 2 ) m QR 4 , CO—T—CH 2 ) m QR 4 , NH(CO)T(CH 2 ) m QR 4 , T—(CH 2 ) m CO 2 R 4 , or T(CH 2 ) m CONR 4 R 5 ; R 6 is alkyl; and Y is a halo counter-ion.