主权项 |
1. A synthetic compound comprising formula (I) wherein R1, R2, R3, R4, and R5 are independently selected from the group consisting of hydrogen, hydroxyl, alkoxy, substituted alkoxy, alkyl carbonyloxy, substituted alkyl carbonyloxy, alkyl carbonyl, substituted alkyl carbonyl, aryl carbonyloxy, substituted aryl carbonyloxy, halogen, amino, nitro, hydrocarbyl and substituted hydrocarbyl; and X, Y, and Z are independently selected from the group consisting of carbon, nitrogen, and oxygen. |