Compounds and methods for treating cancer, viral infections, and allergic conditions

A compound of Formula (IIA), (IIB), (IIC), (IID), (IIE), (IIF), (IIG), or (IIH) a salt thereof, or a stereoisomer thereof:

• wherein:
• each n is independently 1 or 2;
• each P3 is independently hydrogen or a side chain of a natural or unnatural amino acid;
• each X is independently hydrogen or methyl;
• each Y is independently hydrogen, acetyl, tert-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz), fluorenylmethyloxycarbonyl (Fmoc), benzyl, —C(O)R, —SOOR, —COOR, —C(O)NHR, substituted or unsubstituted —(CH2)xaryl, substituted or unsubstituted —(CH2)xheteroaryl, substituted or unsubstituted —(CH2)xcycloalkyl, or substituted or unsubstituted —(CH2)xheterocycle;
• each x is independently 0, 1, or 2;
• each R is independently C1 to C6 alkyl, C3 to C6 cycloalkyl, substituted or unsubstituted heterocycle, substituted or unsubstituted alkylheterocycle, aralkyl, or aryl;
• and
• each Z is independently
• R1 is hydrogen,
• R2 and R3 are each independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted heteroarylalkyl;
• R4 is hydrogen, substituted or unsubstituted alkyl, or a residue of an amino acid, or R3 and R4 can form a ring;
• each R5 is independently hydrogen, substituted or unsubstituted alkyl, or R5 moieties can form a ring;
• and
• each R6 is substituted or unsubstituted aryl.