The present invention relates to a method of treating pain using a compound of formula
wherein R
1
, R
2
, R
3
and R
4
are as defined herein. The invention also relates to certain novel derivatives of formula (I).
本发明涉及一种利用公式中的化合物治疗疼痛的方法,其中R1、R2、R3和R4如本文所定义。该发明还涉及公式(I)的某些新颖衍
生物。