| 摘要 |
<p>This invention relates to compounds having the following structure: wherein Y is O, X is O, bond alpha is absent and bond beta is present, or Y is H, X is CH, bond alpha is present, and bond beta is absent; atom Z is a carbon and bonds chi, delta and gamma are present, or atom Z is a nitrogen and bonds chi, delta and gamma are absent, or atom Z is a nitrogen and bonds chi and delta are present and gamma is absent. R1, R2, R3, R4, R5, and R6 are various substituents as described in the specification.</p> |
