The invention provides for compounds of formula I: wherein Z is absent or (CRARB)nW; each RA and RB is independently (i) H, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, haloalkyl, each of which may be optionally substituted; (ii) OH, ORc, NH2, NHRc, NRcRc, SH, S(O)mRc; or (iii) RA and RB together form C(O); W is absent, C(O), C(O)O, C(O)NRcRc, O, S(O)m, or NRcRc; Y is an optionally substituted heterocyclic, optionally substituted heteroaryl, optionally substituted cycloalkyl, optionally substituted aryl, or NRXRY; wherein Rx and Ry are each independently H, alkyl or aryl; X1 is selected from the group consisting of halogen, methyl, and hydroxyl; X2 is a halogen; each Rc is independently alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aralkyl, or heteroaralkyl, each of which may be optionally substituted; m is O, 1, or 2; and n is 1, 2, 3, 4, 5, or 6; and pharmaceutically acceptable salts thereof.