Synthesis and biological characterization of (3R,4R)-4-(2-(benzhydryloxy)ethyl)-1-((R)-2-hydroxy-2-phenylethyl)-piperidin-3-ol and its stereoisomers for activity toward monoamine transporters

Mechanistic Studies Yield Improved Protocols for Base-Catalyzed Anti-Markovnikov Alcohol Addition Reactions

The catalytic anti-Markovnikov addition of alcohols to simple alkenes is a longstanding synthetic challenge. We recently disclosed the use of organic superbase catalysis for the nucleophilic addition of alcohols to activated styrene derivatives. This article describes mechanistic studies on this reversible reaction, including thermodynamic and kinetic profiling as well as computational modeling. Our findings show the negative entropy of addition is counterbalanced by an enthalpy that is most favored in nonpolar solvents. However, a large negative alcohol rate order under these conditions indicates excess alcohol sequesters the active alkoxide ion pairs, slowing the reaction rate. These observations led to an unexpected solution to a thermodynamically challenging reaction: use of less alcohol enables faster addition, which in turn allows for lower reaction temperatures to counteract Le Chatelier's principle. Thus, our original method has been improved with new protocols that do not require excess alcohol stoichiometry, enable an expanded alkene substrate scope, and allow for the use of more practical catalyst systems. The generality of this insight for other challenging hydroetherification reactions is also demonstrated through new alkenol cyclization and oxa-Michael addition reactions.

Simultaneous Multiple MS Binding Assays for the Dopamine, Norepinephrine, and Serotonin Transporters

In this work, we present label-free, mass-spectrometry-based binding assays (MS Binding Assays), targeting the human dopamine, norepinephrine, and serotonin transporters (hDAT, hNET, and hSERT) in simultaneous binding experiments. Using a validated LC-ESI-MS/MS method for quantification of the selective dopamine transporter inhibitor (R,R)-4-(2-benzhydryloxyethyl)-1-(4-fluorobenzyl)piperidin-3-ol ((R,R)-D-84), the selective norepinephrine transporter inhibitor (S,S)-reboxetine, and the selective serotonin reuptake inhibitor (S)-citalopram, binding affinities at the three monoamine transporters could be characterized simultaneously in a single binding experiment. The performed simultaneous saturation and competition experiments yielded results that are in good accordance with those determined in MS Binding Assays addressing the monoamine transporters individually. The results obtained from this study underscore the potential of MS Binding Assays for simultaneous affinity determination at different targets, which is difficult to accomplish with conventional radioligand binding assays.

Two stereocentered HKR of anti-β,β′-diphenylpropanoxirane and anti-3-phenylethyloxiranes catalysed by Co(iii)(salen)-OAc complex: enantioselective synthesis of (+)-sertraline and (+)-naproxen

Two stereocentered HKR of anti-β,β′-diphenylmethyloxirane and anti-3-phenylethyloxiranes gives enantiopure anti-1,2-diols and oxiranes. This method is utilised for the synthesis of (+)-sertraline and (+)-naproxen.

The novel trisubstituted pyran derivative D-142 has triple monoamine reuptake inhibitory activity and exerts potent antidepressant-like activity in rodents

Major depression disorder is a significant health problem with 10-20% of all adults suffering from this disease. The underlying causes of depression are still unclear and 15% of depressed patients are resistant to all known therapies. Monoamine therapies have so far been the most successful approach for treating depression. Triple monoamine reuptake inhibitors have recently been implicated in generation of potent antidepressant activity while possibly exhibiting a low side-effect profile in addition to treating anhedonia. The additional, previously under-appreciated involvement of dopaminergic systems in depression prompted our efforts to develop novel asymmetric trisubstituted and disubstituted pyran derivatives as triple reuptake inhibitors. One of the lead compounds, D-142, exhibited uptake inhibition (K(i)) values of 29.3 nM, 14.7 nM and 59.3 ± 13.7 nM for norepinephrine, serotonin and dopamine transporters, respectively. Its affinity for serotonin transporter was comparable to fluoxetine, a well known SSRI. In the rat forced swimming test, compound D-142 exhibited potent antidepressant activity in the dose range tested (2.5, 5 and 10mg/kg) and was far more efficacious than the reference compound imipramine. In the mouse tail suspension test, compound D-142 reduced immobility in a dose (2.5, 5 and 10mg/kg) dependent manner, indicating a potent antidepressant effect. In locomotor activity tests, compound D-142 did not exhibit any stimulation in the same dose ranges. In the extended CNS receptors screening assay this molecule exhibited little or no non-specific interaction in the CNS, indicating high specificity for monoamine transporters. These results advance D-142 as a potential potent antidepressant.