Provided are piperazine derivative compounds of the general formula (I), wherein the variables are as defined in the specification. Examples of the compounds include (S)-1-(2,2-diphenylacetyl)-4-phenylpiperazine-2-carboxylic acid and (S)-4-(1-benzyl-3-methyl-1H-pyrazolyl)-N-(N,N-dimethylsulfamoyl)-1-(2,2-diphenylacetyl)piperazine-2-carboxamide. The compounds are antagonists of the angiotensin II Type 2 (AT2) receptor. The compounds may be useful for the treatment of pain, cancer and osteoporosis.