Patent ID: 7446094

Claim:
A purified compound of general formula I: wherein R 1 are each independently selected from the group consisting of hydrogen, halogen, cyano, hydroxyl, nitro, azido, substituted or unsubstituted alkyl, substituted or unsubstituted alkylidene, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group and substituted or unsubstituted acyl; R 3 groups are each independently selected from the group consisting of hydrogen, halogen, cyano, hydroxyl, nitro, azido, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group and substituted or unsubstituted acyl R 4 groups are each independently selected from NR 2 , O and S; and R 2 groups are each independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkoxy and substituted or unsubstituted acyl, or a pharmaceutically acceptable salt, derivative, prodrug or stereoisomer thereof.