A compound of Formula B: wherein: R 1 is -C(=O)NHOH; X 2 is a bond, -C 1 -C 6 alkylene-, -C 2 -C 6 alkenylene-, -C 2 -C 6 alkynylene-, -C 1 -C 6 heteroalkylene-, C 1 -C 6 fluoroalkylene, C 2 -C 6 fluoroalkenylene, C 1 -C 6 haloalkylene, C 2 -C 6 haloalkenylene, -C 1 -C 6 alkylene-O-, -C 1 -C 3 alkylene-O-C 1 -C 3 alkylene-, -C 1 -C 6 alkylene-NH-, -C 1 -C 3 alkylene-NH-C 1 -C 3 alkylene -, -C 1 -C 6 alkylene-C(=O)NH-, -C 1 -C 3 alkylene-C(=O)NH-C 1 -C 3 alkylene -, -C 1 -C 6 alkylene-NHC(=O)-, -C 1 -C 3 alkylene-NHC(=O)-C 1 -C 3 alkylene-, -C 1 -C 6 alkylene-S-, -C 1 -C 3 alkylene-S-C 1 -C 3 alkylene-, -C 1 -C 6 alkylene-S(=O)-, -C 1 -C 3 alkylene-S(=O)-C 1 -C 3 alkylene, -C 1 -C 6 alkylene-S(=O) 2 -,-C 1 -C 3 alkylene-S(=O) 2 -C 1 -C 3 alkylene,-C(=O)-, or -C(=)-C 1 -C 6 alkylene; R 2 is a substituted or unsubstituted group selected from aryl, heteroaryl, C 3 -C 10 cycloalkyl, and C 2 -C 10 heterocycloalkyl; where if R 2 is substituted, then R 2 is substituted with 1, 2, or 3 groups selected from among halogen, C 1 -C 6 alkoxy, C 1 -C 6 fluoroalkoxy, aminoC 1 -C 6 alkoxy, C 1 -C 3 alkylaminoC 1 -C 3 alkoxy, hydroxyC 1 -C 3 alkylaminoC 1 -C 3 alkoxy, C 2 -C 8 heterocycloalkylC 1 -C 3 alkoxy, C 2 -C 8 heterocycloalkylC 1 -C 2 alkyl, -CN, -NO 2, -CO 2 R 10, -C(=O)R 11, -S-R 11, -S(=O)-R 11,-S(=O) 2 -R 11, -NR 10 C(=O)-R 11, -C(=O)N(R 10) 2, -S(=O) 2 N(R 10) 2, -NR 10 S(=O) 2 -R 11, OC(=O)N(R 10) 2, -NR 10 C(=O)O-R 11, -OC(=O)O-R 11, -NHC(=O)NH-R 11, -OC(=O)-R 11,-N(R 10) 2, -C 1 -C 2 alkylN(R 10) 2, C 1 -C 6 alkyl, C 1 -C 6 fluoroalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 heteroalkyl, C 3 -C 8 cycloalkyl, substituted or unsubstituted C 2 -C 10 heterocycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl; R 10 is hydrogen, or a substituted or unsubstituted group selected from among C 1 -C 6 alkyl C 1 -C 6 fluoroalkyl, C 1 -C 6 heteroalkyl, C 3 -C 8 cycloalkyl, C 2 -C 8 heterocycloalkyl, aryl, and heteroaryl; R 11 is a substituted or unsubstituted group selected from among C 1 -C 6 alkyl, C 1 -C 6 fluoroalkyl, C 3 -C 8 cycloalkyl, C 2 -C 8 heterocycloalkyl, aryl, and heteroaryl; each R 3 is independently hydrogen, substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted C 2 -C 6 alkenyl, substituted or unsubstituted C 2 -C 6 alkynyl, substituted or unsubstituted C 1 -C 6 alkoxy, substituted or unsubstituted C 1 -C 6 fluoroalkoxy, substituted or unsubstituted C 1 -C 6 heteroalkyl, substituted or unsubstituted phenyl, or C 1 -C 6 aminoalkyl; or a pharmaceutically acceptable salt, or pharmaceutically acceptable N-oxide thereof. R 1 is -C(=O)NHOH; X 2 is a bond, -C 1 -C 6 alkylene-, -C 2 -C 6 alkenylene-, -C 2 -C 6 alkynylene-, -C 1 -C 6 heteroalkylene-, C 1 -C 6 fluoroalkylene, C 2 -C 6 fluoroalkenylene, C 1 -C 6 haloalkylene, C 2 -C 6 haloalkenylene, -C 1 -C 6 alkylene-O-, -C 1 -C 3 alkylene-O-C 1 -C 3 alkylene-, -C 1 -C 6 alkylene-NH-, -C 1 -C 3 alkylene-NH-C 1 -C 3 alkylene -, -C 1 -C 6 alkylene-C(=O)NH-, -C 1 -C 3 alkylene-C(=O)NH-C 1 -C 3 alkylene -, -C 1 -C 6 alkylene-NHC(=O)-, -C 1 -C 3 alkylene-NHC(=O)-C 1 -C 3 alkylene-, -C 1 -C 6 alkylene-S-, -C 1 -C 3 alkylene-S-C 1 -C 3 alkylene-, -C 1 -C 6 alkylene-S(=O)-, -C 1 -C 3 alkylene-S(=O)-C 1 -C 3 alkylene, -C 1 -C 6 alkylene-S(=O) 2 -,-C 1 -C 3 alkylene-S(=O) 2 -C 1 -C 3 alkylene,-C(=O)-, or -C(=)-C 1 -C 6 alkylene; R 2 is a substituted or unsubstituted group selected from aryl, heteroaryl, C 3 -C 10 cycloalkyl, and C 2 -C 10 heterocycloalkyl; where if R 2 is substituted, then R 2 is substituted with 1, 2, or 3 groups selected from among halogen, C 1 -C 6 alkoxy, C 1 -C 6 fluoroalkoxy, aminoC 1 -C 6 alkoxy, C 1 -C 3 alkylaminoC 1 -C 3 alkoxy, hydroxyC 1 -C 3 alkylaminoC 1 -C 3 alkoxy, C 2 -C 8 heterocycloalkylC 1 -C 3 alkoxy, C 2 -C 8 heterocycloalkylC 1 -C 2 alkyl, -CN, -NO 2, -CO 2 R 10, -C(=O)R 11, -S-R 11, -S(=O)-R 11,-S(=O) 2 -R 11, -NR 10 C(=O)-R 11, -C(=O)N(R 10) 2, -S(=O) 2 N(R 10) 2, -NR 10 S(=O) 2 -R 11, OC(=O)N(R 10) 2, -NR 10 C(=O)O-R 11, -OC(=O)O-R 11, -NHC(=O)NH-R 11, -OC(=O)-R 11,-N(R 10) 2, -C 1 -C 2 alkylN(R 10) 2, C 1 -C 6 alkyl, C 1 -C 6 fluoroalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 heteroalkyl, C 3 -C 8 cycloalkyl, substituted or unsubstituted C 2 -C 10 heterocycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl; R 10 is hydrogen, or a substituted or unsubstituted group selected from among C 1 -C 6 alkyl C 1 -C 6 fluoroalkyl, C 1 -C 6 heteroalkyl, C 3 -C 8 cycloalkyl, C 2 -C 8 heterocycloalkyl, aryl, and heteroaryl; R 11 is a substituted or unsubstituted group selected from among C 1 -C 6 alkyl, C 1 -C 6 fluoroalkyl, C 3 -C 8 cycloalkyl, C 2 -C 8 heterocycloalkyl, aryl, and heteroaryl; each R 3 is independently hydrogen, substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted C 2 -C 6 alkenyl, substituted or unsubstituted C 2 -C 6 alkynyl, substituted or unsubstituted C 1 -C 6 alkoxy, substituted or unsubstituted C 1 -C 6 fluoroalkoxy, substituted or unsubstituted C 1 -C 6 heteroalkyl, substituted or unsubstituted phenyl, or C 1 -C 6 aminoalkyl; or a pharmaceutically acceptable salt, or pharmaceutically acceptable N-oxide thereof.