Immunosuppressive compounds and therapeutics

A method for improving survival and function of a transplanted tissue, comprising administering to the tissue a therapeutically-effective amount of a compound of Formula II or Formula III:

• Wherein:
• (i) X is S or P;
• (ii) Y1 and Y2 are each independently O or N;
• and
• (iii) R1, R2 and R10 are each independently selected from the group consisting of:
• a) H or OH;
• b) a straight- and branched-chain alkyl having one to twelve carbon atoms;
• c) an alkylidene that is a divalent radical having one to twelve carbon atoms;
• d) an alkenyl that is straight- and branched-chain alkenyl groups having from two to twelve carbon atoms;
• e) an alkynyl that is straight- and branched-chain alkynyl groups having from two to twelve carbon atoms;
• f) a cycloalkyl that is saturated or partially unsaturated carbocycles having from three to twelve carbon atoms, including bicyclic and tricyclic cycloalkyl structures;
• g) a heterocycloalkyl that is a saturated or partially unsaturated monocyclic radical containing carbon atoms, preferably with 4 or 5 ring carbon atoms, and with at least one heteroatom selected from nitrogen, oxygen (e.g., monosaccharide) and sulfur;
• h) an aryl or heteroaryl that have monocyclic and polycyclic unsaturated or aromatic ring structures, with “aryl” referring to those that are carbocycles and “heteroaryl” referring to those that are heterocycles;
• i) an alkoxy that is a radical —O-alkyl;
• j) an aryloxy;
• k) a cycloalkoxyl;
• l) an alkylthio;
• m) an alkylamino;
• n) an arylthio;
• o) an arylamino;
• p) a cycloalkylthio;
• q) a cycloalkylamino;
• r) a heteroarylthio;
• s) a heteroarylamino;
• t) a halogen;
• wherein every member in each group can be taken independently or combined via covalent bond in any order with some or all members of any group defined above to the extent that these combinations give rise to chemically feasible entities;
• and
• wherein each of the groups ‘b’ through ‘s’ can contain or be substituted by any one or more functional groups taken from the functional group pool listed below either singularly, in plurality or in combination with other members of the functional group, which functional group pool is consisting of ether, thioether, amine, nitro, nitrile, sulfoxides, sulfones, ester, amide, hydroxamic acid, sulfonamides, sulfamide, ureas, sulfimines, sulfonylureas, carbamates, thiocarbamates, carbonates and hydroxyl.