Immunosuppressive compounds and therapeutics

1. 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) Y 1 and Y 2 are each independently O or N; and

(iii) R 1 , R 2 and R 10 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.

2. The method of claim 1 , wherein the alkyl is selected from the group consisting of methyl (Me), ethyl (Et), n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl (t-Bu), pentyl, isopentyl, tert-pentyl, hexyl, and isohexyl.

3. The method of claim 1 , wherein the alkyl is an alkyl having from 1 to 8 carbon atoms.

4. The method of claim 1 , wherein the alkyl is a substituted alkyl selected from the group consisting of fluoromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl, 3-fluoropropyl, hydroxymethyl, 2-hydroxyethyl, and 3-hydroxypropyl.

5. The method of claim 1 , wherein the alkylidene is selected from the group consisting of CH 2 , CHCH 3 , and (CH 3 ) 2 .

6. The method of claim 1 , wherein the alkenyl is selected from the group consisting of prop-2-enyl, but-3-enyl, hex-3-enyl, 2-methylprop-2-enyl, and hept-2-enyl.

7. The method of claim 1 , wherein the cycloalkyl is selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.

8. The method of claim 1 , wherein the aromatic ring structures in the aryl or heteroaryl is selected from the group consisting of phenyl, naphthyl, 1,2,3,4-tetrahydronaphthyl, furyl, thienyl, pyrrolyl, pyridinyl, pyrazolyl, imidazolyl, pyrazinyl, pyridazinyl, 1,2,3-triazinyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1-H-tetrazol-5-yl, indolyl, quinolinyl, benzofuranyl, benzothiophenyl (thianaphthenyl), and a fused-ring structure or bridge.

9. The method of claim 8 , wherein a fused-ring structure or bridge is OCH 2 .

10. The method of claim 1 , wherein the alkoxy is selected from the group consisting of methoxy, ethoxy, propoxy.

11. The method of claim 1 , wherein the halogen is selected from the group consisting of chlorine, fluorine, bromine and iodine.

12. The method of claim 1 , wherein Formula II refers to a compound of Formula IV

13. The method of claim 12 , wherein the compound of Formula IV is in a mono or di salt form.

14. The method of claim 1 , wherein Formula III refers to a compound of Formula V

15. The method of claim 14 , wherein the compound of Formula V is in a mono or di salt form.