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The unusual activity differences of carbon linked versus oxygen linked 2-substituted piperazines as α7 nicotinic acetylcholine receptor agonists led to a conformational study of several examples. The conformational preferences of which are absent from the literature. We report the first study and explanation of the conformational preference of 2-substiturted piperazines and show an example of how this preference controls binding in a pharmaceutically relevant case. In all cases the axial conformation for these 1-acyl and 1 aryl 2-substituted piperazines was found to be preferred. For the ether linked compounds, the axial conformation was found to be further stabilized by an intramolecular hydrogen bond. The axial orientation also places the basic and pyridyl nitrogens into a special orientation that closely mimics nicotine. Molecular modeling studies confirm that the R enantiomers of the compounds can bind to the α7 nicotinic acetylcholine receptor with the basic and pyridyl nitrogens colocalized with their counterparts in Epibatidine.

HSP90 continues to be a target of interest for neurodegeneration indications. Selective knockdown of the HSP90 cytosolic isoforms α and β is sufficient to reduce mutant huntingtin protein levels in vitro. Chemotype-dependent binding conformations of HSP90α/β appear to strongly influence isoform selectivity. The rational design of HSP90α/β inhibitors selective versus the mitochondrial (TRAP1) and endoplasmic reticulum (GRP94) isoforms offers a potential mitigating strategy for mechanism-based toxicities. Better tolerated HSP90 inhibitors would be attractive for targeting chronic neurodegenerative diseases such as Huntington’s disease.

A series of androgen receptor modulators based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones was synthesized and evaluated in an androgen receptor transcriptional activation assay. The most potent analogues from the series exhibited single-digit nanomolar potency in vitro. Compound 18h demonstrated full efficacy in the maintenance of muscle weight, at 10 mg/kg, with reduced activity in prostate weight in an in vivo model of androgen action.

A series of potent retinoid X receptor (RXR) selective ligands were designed and prepared. The lead compound 6a, showed good binding (Kd; 3–7 nM) and transactivation (EC50; 19–24 nM) to the RXR subfamily of retinoid receptors. More importantly, a small variation on the aromatic ring moiety led to 6b, which had less residual RAR agonist activity with RXR binding and potency of 4–5 nM and 5–13 nM, respectively.

A series of potent retinoid X receptor (RXR) selective ligands was designed and prepared. The lead compound 7a showed good binding (K i ; 20–50 nM) and transactivation (EC 50 ; 40–50 nM) to the RXR subfamily of retinoid receptors. More importantly, small variations in the geometry of the cyclopentane ring moiety led to 9 , one of the most potent RXR agonists to date (K i : 3–8 nM; EC 50 : 3–4 nM).