Patent ID: 7176232

Claim:
An isolated compound having the structure (I): wherein: R 1 to R 3 are each independently —H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, heterocyclic, substituted heterocyclic, cycloalkyl, substituted cycloalkyl, alkoxy, substituted alkoxy, thioalkyl, substituted thioalkyl, hydroxy, halogen, amino, amido, carboxyl, —C(O)H, acyl, oxyacyl, carbamate, sulfonamide, or sulfuryl, Each R 4 is independently alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl, substituted aryl, cycloalkyl, substituted cycloalkyl; E 1 to E 4 are each independently —O, —NR 5 , or —S, wherein R 5 is —H or C 1 –C 6 alkyl; and X is 0 to 8.