Neuraminidase Inhibitors

A compound of formula (I):

• wherein:
• L1 is —(CRoRo)mC(R4)2(CRoRo)nO(CRoRo)o—;
• R1 is —C(O)(CRoRo)rC(RoR′)(CRoRo)sNH2, —C(O)(CRoRo)rC(RoR′)(CRoRo)sN(H)C(O)(CRoRo)wC(RoR″)(CRoRo)x—NH2, or —C(O)(CRoRo)C(RoR′)(CRoRo)sN(H)C(O)(CRoRo)wC(RoR″)(CRoRo)xN(H)C(O)(CRoRo)yC(RoR″′)(CRoRo)zNH2;
• each occurrence of m, n, o, r, s, w, x, y, or z is independently zero, one, or two;
• each occurrence of Ro is independently H, optionally substituted alkyl, optionally, substituted cycloalkyl, optionally substituted aryl, or optionally substituted heteroaryl;
• R2 is NH2 or —NHC(NH2)NH;
• R3 is H, —OR*, or —CHR*R**;
• R′, R″ and R′″ are each independently an amino acid side chain;
• each occurrence of R4 is independently hydrogen or an optionally substituted group selected from a C1-C6 alkyl group, a 3-7 membered saturated, partially saturated or fully unsaturated monocyclic ring having 0-3 heteroatoms independently selected from nitrogen or oxygen or two occurrences of R4 are taken together with the atom(s) to which they are bound to form an optionally substituted 3-7 membered ring, wherein if one occurrence of R4 is H, then the other occurrence of R4 is not H or —CH3;
• R* and R** are independently, H, OH, —OR5, or optionally substituted C1-C12 alkyl;
• R5 is optionally substituted C1-C6 alkyl, or —C(O)NRoRo;
• X1 is O or CH wherein if X1 is O, then there is a single bond between X1 and X2 and a double bond between X2 and X3;
• and wherein X1 is CH then there is a double bond between X1 and X2 and a single bond between X2 and X3;
• X2 is C;
• and
• X3 is CH or CH2;
• or a pharmaceutically acceptable salt thereof.