1-(2-Hydroxyphenyl)-4-(tert-butoxycarbonyl)piperazine is an intermediate used to synthesize 2-(1-Piperazinyl)-benzenethiol (P480550) which is used to used to prepare 3,5-dioxo-(2H,4H)-1,2,4-triazine as 5-HT1AR ligands. 1-(2-Hydroxyphenyl)-4-(tert-butoxycarbonyl)piperazine is also used to prepare nonpeptidic biaryl inhibitors of human cathepsin K in relation to treatment of osteoporosis.