EGCG-like non-competitive inhibitor of DYRK1A rescues cognitive defect in a down syndrome model.

Overexpression of the chromosome 21 DYRK1A gene induces morphological defects and cognitive impairments in individuals with Down syndrome (DS) and in DS mice models. Aging neurons of specific brain regions of patients with Alzheimer's disease, DS and Pick's disease have increased DYRK1A immunoreactivity suggesting a possible association of DYRK1A with neurofibrillary tangle pathology. Epigallocatechin-3-gallate (EGCG) displays appreciable inhibition of DYRK1A activity and, contrary to all other published inhibitors, EGCG is a non-competitive inhibitor of DYRK1A.

Azetidinimines as a novel series of non-covalent broad-spectrum inhibitors of β-lactamases with submicromolar activities against carbapenemases KPC-2 (class A), NDM-1 (class B) and OXA-48 (class D).

The occurrence of resistances in Gram negative bacteria is steadily increasing to reach extremely worrying levels and one of the main causes of resistance is the massive spread of very efficient β-lactamases which render most β-lactam antibiotics useless. Herein, we report the development of a series of imino-analogues of β-lactams (namely azetidinimines) as efficient non-covalent inhibitors of β-lactamases. Despite the structural and mechanistic differences between serine-β-lactamases KPC-2 and OXA-48 and metallo-β-lactamase NDM-1, all three enzymes can be inhibited at a submicromolar level by compound 7dfm, which can also repotentiate imipenem against a resistant strain of Escherichia coli expressing NDM-1.

Synthesis of Rottlerone Analogues and Evaluation of Their α-Glucosidase and DPP-4 Dual Inhibitory and Glucose Consumption-Promoting Activity.

Our previous study found that desmethylxanthohumol () inhibited α-glucosidase in vitro. Recently, further investigations revealed that dehydrocyclodesmethylxanthohumol () and its dimer analogue rottlerone () exhibited more potent α-glucosidase inhibitory activity than . The aim of this study was to synthesize a series of rottlerone analogues and evaluate their α-glucosidase and DPP-4 dual inhibitory activity.

Rhodium-catalyzed iminoiodane-mediated oxyamidation studies of 5-vinyluracil derivatives using aryl and alkyl sulfamates.

The dirhodium tetraacetate-catalyzed iminoiodane-mediated reaction of 1,3-dimethyl-5-vinyluracil with phenyl sulfamate provided a high yield of 5-(1-acetyl-2-phenylsulfamoyl)ethyluracil via regioselective nucleophilic ring opening by acetate anion of the transiently formed 5-(1,2)-N-phenylsulfonylaziridine intermediate. This 1,2-oxyamidation reaction was found to be general for a variety of aryl- and alkylsulfamates as well as for various 1,3-dialkyl-5-vinyluracil derivatives. Addition of an alcohol to the reaction mixture allowed formation of the corresponding 1-alkoxy products.

Synthesis of tetracyclic oxindoles and evaluation of their α-glucosidase inhibitory and glucose consumption-promoting activity.

A series of tetracyclic oxindole derivatives was synthesized by asymmetric 1, 3-dipole reaction in 2-4 steps in 57-86% overall yields. These compounds were evaluated for α-glucosidase inhibitory and glucose consumption-promoting activity in vitro. Compound 4l competitively and reversibly inhibited α-glucosidase (IC = 3.

Iodine(III)-mediated halogenations of acyclic monoterpenoids.

Five different halofunctionalizations of acyclic monoterpenoids were performed using a combination of a hypervalent iodine(III) reagent and a halide salt. In this manner, the dibromination, the bromo(trifluoro)acetoxylation, the bromohydroxylation, the iodo(trifluoro)acetoxylation or the ene-type chlorination of the distal trisubstituted double bond occurred with excellent selectivity and moderate to good yields.

Synthesis & α-glucosidase inhibitory & glucose consumption-promoting activities of flavonoid-coumarin hybrids.

Aim: The research of novel and potent antidiabetic agents is urgently needed for the control of the exploding diabetic population. We previously reported the synthesis and antidiabetic activity of natural 8-(6"-umbelliferyl)-apigenin (1), but its antidiabetic targets are not known. Therefore, four series of derivatives were synthesized and evaluated for their antidiabetic activities.

DYRK1A inhibition and cognitive rescue in a Down syndrome mouse model are induced by new fluoro-DANDY derivatives.

Inhibition of DYRK1A kinase, produced by chromosome 21 and consequently overproduced in trisomy 21 subjects, has been suggested as a therapeutic approach to treating the cognitive deficiencies observed in Down syndrome (DS). We now report the synthesis and potent DYRK1A inhibitory activities of fluoro derivatives of 3,5-di(polyhydroxyaryl)-7-azaindoles (F-DANDYs). One of these compounds (3-(4-fluorophenyl)-5-(3,4-dihydroxyphenyl)-1H-pyrrolo[2,3-b]pyridine, 5a) was selected for in vivo studies of cognitive rescuing effects in a standard mouse model of DS (Ts65Dn line).

Ketenimines Generated from Ynamides: Versatile Building Blocks for Nitrogen-Containing Scaffolds.

Using ynamides as readily available starting materials, a single step can generate highly reactive ketenimines, which can then undergo a variety of transformations. The choice of the method for generating the ketenimine dictates the outcome of the reaction that can, moreover, be precisely steered through minor variations of the starting material. This Concept gives an overview of the different existing methodologies for this objective, showcasing the diverse nitrogen-containing frameworks that can be obtained by this highly versatile strategy.

Chemodivergent, Tunable, and Selective Iodine(III)-Mediated Bromo-Functionalizations of Polyprenoids.

Mild oxidation of bromides by iodine(III) reagents generated active electrophilic bromination species that were reacted with polyprenoids. By simple and minor variations of an I(III)/Br combination, the reactivity could be selectively steered toward dibromination, oxybromination, or bromocyclization, giving access to a wide array of brominated motifs.

Synthesis of 6-hydroxyaurone analogues and evaluation of their α-glucosidase inhibitory and glucose consumption-promoting activity: Development of highly active 5,6-disubstituted derivatives.

A series of 6-hydroxyaurones and their analogues have been synthesized and evaluated for their in vitro α-glucosidase inhibitory and glucose consumption-promoting activity. These compounds exhibited varying degrees of α-glucosidase inhibitory activity, 11 of them showing higher potency than that of the control standard acarbose (IC=50.30μM).

Base-Mediated Generation of Ketenimines from Ynamides: Direct Access to Azetidinimines by an Imino-Staudinger Synthesis.

Ynamides were used as precursors for the in situ generation of highly reactive ketenimines that could be trapped with imines in a [2+2] cycloaddition. This imino-Staudinger synthesis led to a variety of imino-analogs of β-lactams, namely azetidinimines (20 examples), that could be further functionalized through a broad range of transformations.

A direct label-free MALDI-TOF mass spectrometry based assay for the characterization of inhibitors of protein lysine methyltransferases.

Histone lysine methylation is associated with essential biological functions like transcription activation or repression, depending on the position and the degree of methylation. This post-translational modification is introduced by protein lysine methyltransferases (KMTs) which catalyze the transfer of one to three methyl groups from the methyl donor S-adenosyl-L-methionine (AdoMet) to the amino group on the side chain of lysines. The regulation of protein lysine methylation plays a primary role not only in the basic functioning of normal cells but also in various pathologies and KMT deregulation is associated with diseases including cancer.

Identification of cancer chemopreventive isothiocyanates as direct inhibitors of the arylamine N-acetyltransferase-dependent acetylation and bioactivation of aromatic amine carcinogens.

Aromatic amines (AAs) are chemicals of industrial, pharmacological and environmental relevance. Certain AAs, such as 4-aminobiphenyl (4-ABP), are human carcinogens that require enzymatic metabolic activation to reactive chemicals to form genotoxic DNA adducts. Arylamine N-acetyltransferases (NAT) are xenobiotic metabolizing enzymes (XME) that play a major role in this carcinogenic bioactivation process.

Mallotojaponins B and C: Total Synthesis, Antiparasitic Evaluation, and Preliminary SAR Studies.

The first total syntheses of mallotojaponin B and C as well as several analogues have been achieved. Biological evaluation of the synthesized compounds against Plasmodium falciparum and Trypanosoma brucei have also been carried out.

Design and synthesis of calindol derivatives as potent and selective calcium sensing receptor agonists.

We report the first comprehensive structure-activity study of calindol (4, (R)-N-[(1H-indol-2-yl)methyl]-1-(1-naphthyl)ethanamine), a positive allosteric modulator, or calcimimetic, of the calcium sensing receptor (CaSR). While replacement of the naphthyl moiety of calindol by other aromatic groups (phenyl, biphenyl) was largely detrimental to calcimimetic activity, incorporation of substituents on the 4, 5 or 7 position of the indole portion of calindol was found to provide either equipotent derivatives compared to calindol (e.g.

Halocyclization of Unsaturated Guanidines Mediated by Koser's Reagent and Lithium Halides.

The synthesis of halogenated cyclic guanidines through iodine(III)-mediated umpolung of halide salts is described. Cyclic guanidines of various sizes can be obtained with generally excellent regioselectivities through either a chloro- or a bromocyclization, using Koser's reagent and the corresponding lithium salt.

Iodine(III)-Mediated Diazidation and Azido-oxyamination of Enamides.

In this study we demonstrate that the combination of bis(tert-butylcarbonyloxy)iodobenzene and lithium azide in acetonitrile allows the diazidation of various enamide substrates. The azido-oxyamination of the same substrates can be carried out in the presence of 2,2,6,6-tetramethylpiperidine N-oxide (TEMPO). Control experiments strongly suggest that this latter process occurs through a shift in nature of the in situ generated electrophilic species from a radical to a cation.

GABA(A) receptor subtype-selectivity of novel bicuculline derivatives.

GABA(A) receptors are the major inhibitory neurotransmitter receptors in the central nervous system and are targets of clinically important drugs modulating GABA induced ion flux by interacting with distinct allosteric binding sites. ROD 185 is a previously investigated structural analogue of the GABA site antagonist bicuculline, and a positive allosteric modulator acting via the benzodiazepine binding site. Here, we investigated 13 newly synthesized structural analogues of ROD 185 for their interaction with rat GABA(A) receptors.

Transition-metal-free tunable chemoselective N functionalization of indoles with ynamides.

Two unprecedented N functionalizations of indoles with ynamides are described. By varying the electron-withdrawing group on the ynamide nitrogen atom, either Z-indolo-etheneamides or indolo-amidines can be selectively obtained under the same metal-free reaction conditions. The scope and synthetic potential of these reactions, as well as some mechanistic insights provided by DFT calculations, are reported.

Diastereoselective three-component vinylogous Mannich reaction of nitrogen heterocycles, acyl/sulfonyl chlorides, and silyloxyfurans/pyrroles.

A one-step, 3-component vinylogous Mannich reaction of trimethylsilyloxyfuran or N-protected tert-butyldimethylsilyloxypyrrole with a variety of nitrogen-containing heterocycles in the presence of diverse electrophiles is described. The reaction products were generally obtained in high yields and as a single diastereoisomer having the (R*,R*) relative configuration based on crystallographic studies of several derivatives. Several azaheterocycles were successfully used for this reaction, such as isoquinolines, quinoline, phenanthridine, quinazoline, phthalazine, and β-carboline, and electrophiles included acetyl chloride, methyl chloroformate, methyl chloromalonate, 2-bromobutanoyl chloride, and arylsulfonyl chlorides.

Bioluminescent properties of obelin and aequorin with novel coelenterazine analogues.

The main analytical use of Ca(2+)-regulated photoproteins from luminous coelenterates is for real-time non-invasive visualization of intracellular calcium concentration ([Ca(2+)]i) dynamics in cells and whole organisms. A limitation of this approach for in vivo deep tissue imaging is the fact that blue light emitted by the photoprotein is highly absorbed by tissue. Seven novel coelenterazine analogues were synthesized and their effects on the bioluminescent properties of recombinant obelin from Obelia longissima and aequorin from Aequorea victoria were evaluated.

At a supra-physiological concentration, human sexual hormones act as quorum-sensing inhibitors.

N-acylhomoserine lactone (AHL)-mediated quorum-sensing (QS) regulates virulence functions in plant and animal pathogens such as Agrobacterium tumefaciens and Pseudomonas aeruginosa. A chemolibrary of more than 3500 compounds was screened using two bacterial AHL-biosensors to identify QS-inhibitors (QSIs). The purity and structure of 15 QSIs selected through this screening were verified using HPLC MS/MS tools and their activity tested on the A.

Development of DANDYs, new 3,5-diaryl-7-azaindoles demonstrating potent DYRK1A kinase inhibitory activity.

A series of 3,5-diaryl-1H-pyrrolo[2,3-b]pyridines were synthesized and evaluated for inhibition of DYRKIA kinase in vitro. Derivatives having hydroxy groups on the aryl moieties (2c, 2j-l) demonstrated high inhibitory potencies with Kis in the low nanomolar range. Their methoxy analogues were up to 100 times less active.

Iodine(III)-mediated umpolung of bromide salts for the ethoxybromination of enamides.

Using (diacetoxyiodo)benzene in conjunction with simple bromide salts in ethanol allows the regioselective ethoxybromination of a wide range of enamides, thus yielding highly versatile α-bromo hemiaminals, which can then be engaged in a broad array of transformations.