Abstract: The invention relates to a compound of General Formula (I): wherein R1, R2, R3, R4 and R5 are as defined herein. Compounds and compositions comprising the same exhibit high serum stability and potent activation of the ?? T-cell immune response, so are suitable for use in immunotherapy. The invention also relates to methods of immunotherapy using the compounds of General Formula (I).

Abstract: A ferrocenyl compound having the general formula (I): (I) Het is a substituted or unsubstituted heterocyclic moiety. L1, L2 and L3 are each a linker independently selected from alkylene, alkyleneoxy, alkyleneoxyalkylene, alkylenecarbonyl, alkyleneoxycarbonyl, alkyleneamido, alkyleneoxyamido, alkenylene, alkenyleneoxy, alkenylenecarbonyl, alkenyleneamido, alkynylene, alkynyleneoxy, alkynylenecarbonyl and alkynyleneamido, all of which may be straight chain or branched, substituted or unsubstituted. R1 and R2 are each independently selected from H, substituted or unsubstituted alkyl carbonyl, substituted or unsubstituted aryl carbonyl, substituted or unsubstituted phosphate, substituted or unsubstituted phosphonate and substituted or unsubstituted phosphoramidate. M and n are each 0 or 1 and m+n?0.1.

Abstract: A ferrocenyl compound having the general formula (I): (I) Het is a substituted or unsubstituted heterocyclic moiety. L1, L2 and L3 are each a linker independently selected from alkylene, alkyleneoxy, alkyleneoxyalkylene, alkylenecarbonyl, alkyleneoxycarbonyl, alkyleneamido, alkyleneoxyamido, alkenylene, alkenyleneoxy, alkenylenecarbonyl, alkenyleneamido, alkynylene, alkynyleneoxy, alkynylenecarbonyl and alkynyleneamido, all of which may be straight chain or branched, substituted or unsubstituted. R1 and R2 are each independently selected from H, substituted or unsubstituted alkyl carbonyl, substituted or unsubstituted aryl carbonyl, substituted or unsubstituted phosphate, substituted or unsubstituted phosphonate and substituted or unsubstituted phosphoramidate. M and n are each 0 or 1 and m+n?0.