| abstract |
A compound of formula (I) or, where appropriate, a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof wherein: A represents >C=X or a bond; X represents O or S; Y represents N or N+-O- or a moiety CR10; Z° represents O, CH2, NR or S(O)p; R represents hydrogen, alkyl or alkylcarbonyl; a process for preparing such compounds, pharmaceutical compositions containing such compounds and the use of such compounds and compositions in medicine. |