Hyunsoo Park

In sharp contrast to a previously reported series of 6-anilino imidazopyridazine based Tyk2 JH2 ligands, 6-((2-oxo-N1-substituted-1,2-dihydropyridin-3-yl)amino)imidazo[1,2-b]pyridazine analogs were found to display dramatically improved metabolic stability. The N1-substituent on 2-oxo-1,2-dihydropyridine ring can be a variety of alkyl, aryl, and heteroaryl groups, but among them, 2-pyridyl provided much enhanced Caco-2 permeability, attributed to its ability to form intramolecular hydrogen bonds. Further structure–activity relationship studies at the C3 position led to the identification of highly potent and selective Tyk2 JH2 inhibitor 6, which proved to be highly effective in inhibiting IFNγ production in a rat pharmacodynamics model and fully efficacious in a rat adjuvant arthritis model.

The impact of pharmaceutical materials properties on drug product quality and manufacturability is well recognised by the industry. An ongoing effort across industry and academia, the Manufacturing...

A series of complexes of divalent copper and zinc carrying two systematically substituted 2,2′‐pyridylpyrrolide ligands, designated Lⁿ to indicate the number of pyrrole CF₃ substituents (n = 0, 1, 2), have been studied for their geometric and electronic structures. These reveal the pyridylpyrrolide to be a highly anisotropic nitrogen donor ligand which distorts ML₂ complexes away from both planar and tetrahedral structures. Characterization includes CV and mass spectrometry, which show access to cations beyond conventional maximum metal oxidation states. EPR studies at multiple microwave frequencies of the series Cu(Lⁿ)₂ gave insight into the substituent effect on frontier orbital composition of these complexes. While Cu(L²)₂ exhibited EPR spectra that were roughly comparable to those for typical, tetragonally distorted Cu^II complexes with the SOMO having d_x²_–y² character, the other two complexes exhibited more unusual EPR spectra indicative of their distinct geometry, reminiscent of equatorially‐vacant trigonal bipyramidal hybridization and fully consistent with the X‐ray crystal structure determinations of all three Cu(Lⁿ)₂. DFT calculations map both geometric and delocalization changes upon redox change, and show the relevance of oxidation at the pyrrolide donors rather than at the metal.

Challenging couplings of hindered carboxylic acids with non-nucleophilic amines to form amide bonds can be accomplished in high yields, and in many cases, with complete retention of the adjacent stereogenic centers using the combination of N,N,N′,N′-tetramethylchloroformamidinium hexafluorophosphate (TCFH) and N-methylimidazole (NMI). This method allows for in situ generation of highly reactive acyl imidazolium ions, which have been demonstrated to be intermediates in the reaction. The reagent delivers high reactivity similar to acid chlorides with the ease of use of modern uronium reagents.

There is a significant unmet medical need for more efficacious and rapidly acting antidepressants. Toward this end, negative allosteric modulators of the N-methyl-d-aspartate receptor subtype GluN2B have demonstrated encouraging therapeutic potential. We report herein the discovery and preclinical profile of a water-soluble intravenous prodrug BMS-986163 (6) and its active parent molecule BMS-986169 (5), which demonstrated high binding affinity for the GluN2B allosteric site (K_i = 4.0 nM) and selective inhibition of GluN2B receptor function (IC₅₀ = 24 nM) in cells. The conversion of prodrug 6 to parent 5 was rapid in vitro and in vivo across preclinical species. After intravenous administration, compounds 5 and 6 have exhibited robust levels of ex vivo GluN2B target engagement in rodents and antidepressant-like activity in mice. No significant off-target activity was observed for 5, 6, or the major circulating metabolites met-1 and met-2. The prodrug BMS-986163 (6) has demonstrated an acceptable safety and toxicology profile and was selected as a preclinical candidate for further evaluation in major depressive disorder.

An efficient, concise enantioselective total synthesis of the potent antitumor antibiotic (+)-duocarmycin SA is described. The invented route is based on a disconnection strategy that was devised to facilitate rapid and efficient synthesis of key core compounds to enable preclinical structure-activity relationship investigations. The key tricycle core was constructed with a highly enantioselective indole hydrogenation to set the stereocenter and a subsequent hitherto unexplored vicarious, nucleophilic-substitution/cyclization sequence to effectively forge a final indole ring. Additionally, development of a stable sulfonamide protecting group, capable of mild chemoselective cleavage greatly enhanced sequence yield and throughput. An understanding of key reaction parameters ensured a robust, reproducible sequence easily executable on decagram scales to this highly promising class of compounds.

The purpose of this letter is to document the use of protected chloroethyl and chloropropyl amines as conformationally unrestricted ambiphilic reagents that undergo annulation reactions with Michael acceptors. This reaction is wide in scope and utilizes reagents that are commercially available, inexpensive, and stable. Furthermore, this reaction is easy to execute and proceeds rapidly.