Compounds are provided which have the following formula: 
wherein:
R is hydrogen, alkyl of 1 to 6 carbon atoms, phenyl, or substituted phenyl;
X and Y are each, independently, hydrogen, halogen, cyano, or alkoxy of 1 to 6 carbon atoms; and
m is 1 to 5; or
a pharmaceutically acceptable salt thereof.
                            提供具有以下
化学式的化合物:其中:R为氢、1至6个碳原子的烷基、苯基或取代苯基;X和Y分别独立地为氢、卤素、
氰基或1至6个碳原子的烷氧基;m为1至5;或其药用可接受盐。