| 摘要 |
Compounds of formula (I) or a pharmaceutically acceptable salt thereof:wherein R1, R2 and R3 are various substituent groups; andone of X1 and X2 is N or CR', and the other is NR' or CHR' wherein R' is hydrogen, OH, C1-6alkyl, or C3-7cycloalkyl; or when one of X1 and X2 is N or CR' then the other may be S or O;and their use as pharmaceuticals. |
