Analogs of methyl-piperidinopyrazole (MPP): antiestrogens with estrogen receptor alpha selective activity.

Methyl-piperidino-pyrazole (MPP), an estrogen receptor alpha (ERalpha)-selective antagonist we developed, has a basic side chain (BSC) attached to an ERalpha-selective agonist ligand, methyl-pyrazole-triol (MPT) through an ether linkage. To remove the possibility that metabolic cleavage of the BSC in MPP would regenerate MPT, we have replaced the N-piperidinylethoxy moiety with an N-piperidinylpropyl group, giving MPrP. This new analog retains the high ERalpha-selective binding affinity and antagonist potency of MPP.