Aryl diazonium intermediates enable mild DNA-compatible C-C bond formation for medicinally relevant combinatorial library synthesis

Forging carbon-carbon (C-C) linkage in DNA-encoded combinatorial library synthesis represents a fundamental task for drug discovery, especially with broad substrate scope and exquisite functional group tolerance. Here we reported the palladium-catalyzed Suzuki-Miyaura, Heck and Hiyama type cross-coupling via DNA-conjugated aryl diazonium intermediates for DNA-encoded chemical library (DEL) synthesis. Starting from commodity arylamines, this synthetic route facilely delivers vast chemical diversity at a mild temperature and pH, thus circumventing damage to fragile functional groups. Given its orthogonality with traditional aryl halide-based cross-coupling, the aryl diazonium-centered strategy expands the compatible synthesis of complex C-C bond-connected scaffolds. In addition, DNA-tethered pharmaceutical compounds (e.g., HDAC inhibitor) are constructed without decomposition of susceptible bioactive warheads (e.g., hydroxamic acid), emphasizing the superiority of the aryl diazonium-based approach. Together with the convenient transformation into an aryl azide photo-crosslinker, aryl diazonium's DNA-compatible diversification synergistically demonstrated its competence to create medicinally relevant combinatorial libraries and investigate protein-ligand interactions in pharmaceutical research.

Synthesis and Biological Evaluation of Hydroxylated Monocarbonyl Curcumin Derivatives as Potential Inducers of Neprilysin Activity

BACKGROUND

Alzheimer's disease (AD) involves impairment of Aβ clearance. Neprilysin (NEP) is the most efficient Aβ peptidase. Enhancement of the activity or expression of NEP may provide a prominent therapeutic strategy against AD.

AIMS

Ten hydroxylated monocarbonyl curcumin derivatives were designed, synthesized and evaluated for their NEP upregulating potential using sensitive fluorescence-based Aβ digestion and inhibition assays.

RESULTS

Compound 4 was the most active one, resulting in a 50% increase in Aβ cleavage activity. Cyclohexanone-bearing derivatives exhibited higher activity enhancement compared to their acetone counterparts. Inhibition experiments with the NEP-specific inhibitor thiorphan resulted in dramatic cleavage reduction. Conclusion: The increased Aβ cleavage activity and the ease of synthesis of 4 renders it an extremely attractive lead compound.

First aromatic amine organocatalysed activation of α,β-unsaturated ketones

The first example of a chiral aromatic amine used to activate α,β-unsaturated ketones in aminocatalysis.

An in Situ Generated Palladium on Aluminum Oxide: Applications in Gram-Scale Matsuda-Heck Reactions

In situ generated palladium on aluminum oxide provides an active catalytic system for Matsuda-Heck reactions in gram-scale. The novel catalyst proceeded through a significantly higher catalytic activity compared to the classical Pd/C system. Based on the high catalytic activity the first α,β,β-triarylation of methyl acrylate in good yields could be provided in one-step.

Cooperative titanocene and phosphine catalysis: accelerated C-X activation for the generation of reactive organometallics

The study presented herein describes a reductive transmetalation approach toward the generation of Grignard and organozinc reagents mediated by a titanocene catalyst. This method enables the metalation of functionalized substrates without loss of functional group compatibility. Allyl zinc reagents and allyl, vinyl, and alkyl Grignard reagents were generated in situ and used in the addition to carbonyl substrates to provide the corresponding carbinols in yields up to 99%. It was discovered that phosphine ligands effectively accelerate the reductive transmetalation event to enable the metalation of C-X bonds at temperatures as low as -40 °C. Performing the reactions in the presence of chiral diamines and amino alcohols led to the enantioselective allylation of aldehydes.