Compounds of formula (I) or a pharmaceutically acceptable salt thereof:
##STR1##
- wherein R1, R2 and R3 are various substituent
groups; and
- one 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.
|
|
|
