Compounds having the following structure wherein R1, R2, R3, R4, m and n are as defined in the specification, in vivo-hydrolysable precursors thereof, pharmaceutically-acceptable salts thereof, the use in therapy and pharmaceutical compositions and methods of treatment using the same.
                            具有以下结构的化合物,其中R1、R2、R3、R4、m和n如规范中定义,其体内可
水解的前体,其药用可接受的盐,以及在治疗中的使用、制药组合物和使用相同方法的治疗方法。