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Two strategies based on kinetic resolution(s) of chiral alanes and providing enantioenriched syn homoallylamines are reported. The first implies a single kinetic resolution of the alane using camphor; the second requires two sequential kinetic resolutions using the synergistic combination of (-)-camphor/(R)-tert-butylsulfinamide-derived imines. This syn selectivity, specific to the use of allyaluminum, opens the way to the preparation of valuable building blocks as illustrated by the synthesis of (+)-epilupinamine. [ABSTRACT FROM AUTHOR]

An unprecedented reactivity of CF3-TMS has been revealed, which exploits the basic character of the generated [CF3-] capable of delivering dichloromethide from dichloromethane with subsequent transfer to nitrones under smooth conditions. The proton-abstraction pathway was demonstrated through isotopic labeling experiments in CD2Cl2. The same reaction was achieved in acetonitrile with the introduction of a cyanomethyl group onto the nitrones. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a convenient and efficient synthesis of new complexing surfactants from d-galacturonic acid and n-octanol as renewable raw materials in a two-step sequence. In the first step, simultaneous O-glycosidation–esterification under Fischer conditions was achieved. The anomeric ratio of the products was studied based on the main experimental parameters and the activation mode (thermal or microwave). In the second step, aminolysis of the n-octyl ester was achieved with various functionalized primary amines under standard thermal or microwave activation. The physico-chemical properties of these new amphiphilic ligands were measured and these compounds were found to exhibit interesting surface properties. Complexing abilities of one uronamide ligand functionalized with a pyridine moiety toward Cu(II) ions was investigated in solution by EPR titrations. A solid compound was also synthesized and characterized, its relative structure was deduced from spectroscopic data. [Copyright &y& Elsevier]

Abstract: 3,6-Anhydro-1-(aryl or alkylamino)-1-deoxy-d-sorbitol derivatives have been prepared in four steps from isosorbide, a by-product from the starch industry. The inhibitory activities of these new compounds have been evaluated towards 13 glycosidases. A first lead-compound was identified, which inhibited β-N-acetylglucosaminidase from bovine kidney (82% inhibition at 1mM). [Copyright &y& Elsevier]

Abstract: The synthesis of a series of aryl-substituted cyclic sugar imines was performed via a tandem nucleophilic addition/substitution reaction. The so-obtained ketimines displayed fucosidase inhibitory activities (IC50 =46–556μM). Their reduced counterparts were prepared and assayed after addition of sodium borohydride to the enzymatic assay stock solution. The pyrrolidines strongly inhibit fucosidase (IC50 =0.65–150μM). [Copyright &y& Elsevier]

Abstract: The synthesis of a fully deprotected ketimine-type iminosugar is reported, starting from commercial d-mannose diacetonide. An appropriate solvent system was critical for the success of the key tandem addition/cyclization reaction. Reduction of the imine was also achieved to yield the corresponding pyrrolidine in a stereoselective manner. The cyclic sugar imine displayed modest fucosidase inhibitory activity when compared to the saturated analogue. [Copyright &y& Elsevier]

The biological activity of unsaturated iminosugars has not yet been extensively studied because of a lack of general synthetic methods. A practical synthesis of these cyclic ketimine sugars was developed, which was based on a tandem addition-cyclization reaction of a Grignard reagent to a ω-methanesulfonylglycononitrile. [ABSTRACT FROM AUTHOR]

Abstract: A short and practical procedure for the preparation of C-2 substituted polyhydroxypyrrolidines is described. The C-2 substituent is introduced by a stereoselective addition of a Grignard reagent to a 2,3,5-protected aldofuranose and the cyclization to the pyrrolidine ring system is performed through a bis-mesylation/double nucleophilic displacement sequence. The efficiency of the methodology was demonstrated by its application to the synthesis of HomoDMDP and DMDP. [Copyright &y& Elsevier]

Abstract: Polyhydroxy 4-azaspiro[2.4]heptane derivatives (spirocyclopropyl iminosugars) were prepared in four to six steps from readily available protected aldoses. The key step of the reaction sequence involves a titanium-mediated aminocyclopropanation of glycononitriles with subsequent cyclization. Five new polyhydroxypyrrolidines so-obtained have been evaluated for their ability to inhibit 16 glycosidases. One of them exhibits selective inhibition of α-l-fucosidase from bovine kidney (K i =1.6μM, competitive). [Copyright &y& Elsevier]

Abstract: Chitin synthase is an enzyme involved in the biosynthesis of chitin, a major structural component of the cell wall of many fungi. Since chitin is absent in vertebrates, chitin synthase has been envisaged as a valuable target in the search for new antifungal agents. In this report, a series of C-2 substituted polyhydroxypyrrolidines were designed and synthesized with the aim of mimicking the glycosylcation involved at the transition state of the enzymatic reaction governed by chitin synthase. Some of these models displayed chitin synthase inhibition in the millimolar range. However, no significant antifungal activity was noted on a panel of fungal strains. [Copyright &y& Elsevier]

We identified 6-deoxy-homoDMDP as a potent inhibitor of chitin synthase (Ki=38?µM), displaying an uncompetitive inhibition pattern. Dual inhibition was also performed with the enzymatic reaction product uridine 5'-diphosphate in order to evaluate the concurrent effect of both inhibitors. An interaction coefficient a of 0.9 was found, revealing synergistic inhibition. [ABSTRACT FROM AUTHOR]

Pyrrolidine amino-sugars, cyclic iminoalditols as well as linear aminoalditols in 4-amino-l-erythrose and 4-amino-5-deoxy-l-ribose series were synthesised by asymmetric hetero-Diels–Alder reaction followed by chemical transformations. 4-Amino-4-deoxy-l-erythrose and 4-amino-4,5-dideoxy-l-ribose were potent β-d-glucosidase, α-d-mannosidase, α- and β-d-galactosidase inhibitors. We have shown that the ribose derivative was a very potent inhibitor of α-d-mannosidase. [Copyright &y& Elsevier]

Resin-bound α-keto mesylates were cleaved under acidic conditions (TFA/CH2Cl2) in the presence of a variety of aryl or alkyl thiols to give the corresponding thioethers. Access to the target compounds via standard nucleophilic displacement proved to be much less efficient. The stereochemical outcome of the reaction suggested formation of a highly reactive α-keto carbocation trapped in situ by the thiol acting as a scavenger. [Copyright &y& Elsevier]

A concise enantioselective synthesis of 2,5-imino-2,5,6-trideoxy-d-manno-heptitol (6-deoxy-homoDMDP) and 2,5-imino-2,5,6-trideoxy-l-gulo-heptitol has been achieved. These compounds were used as stereochemical references to establish the absolute configuration of the corresponding naturally occurring stereoisomers, recently isolated from Hyacinthus orientalis. [Copyright &y& Elsevier]

A 1,3‐dipolar cycloaddition reaction of carbohydrate‐derived five‐membered cyclic ketonitrones with alkynes and alkenes was developed as an efficient and regioselective process to access highly functionalised isoxazolines and isoxazolidines bearing a quaternary centre α to the nitrogen atom. The latter compounds were used as intermediates for the synthesis of unprecedented ring‐junction‐substituted polyhydroxylated pyrrolizidines and indolizidines. These compounds were evaluated against a panel of glycosidases, and showed moderate but selective inhibition of α‐glucosidases. [ABSTRACT FROM AUTHOR]

The dichloromethylation and cyanomethylation of nitrones in the presence of the strong base [CF3-] is described. [ABSTRACT FROM AUTHOR]

Cycloadditions of nitrones with alkynes usually occur best under heat activation. Due to the instability of the formed isoxazolines, alternative activation methods must be found. Here, hyperbaric conditions are used to transform nitrones generated from unprotected carbohydrates into the corresponding polyhydroxy-isoxazolines at room temperature. The reaction proved completely regioselective in favor of the 5-substituted 4-isoxazolines, and the products are obtained in good yields as mixtures of the two possible diastereoisomers. Further transformations into biologically valuable targets are described. The whole synthesis constitutes a very straightforward procedure for the transformation of aldoses, and is highly compatible with the principles of green chemistry. [ABSTRACT FROM AUTHOR]

IspG (also called GcpE) is an oxygen‐sensitive [4Fe‐4S] enzyme catalyzing the penultimate step of the methylerythritol phosphate (MEP) pathway, a validated target for drug development. It converts 2‐C‐methyl‐d‐erythritol‐2,4‐cyclo‐diphosphate (MEcPP) into (E)‐4‐hydroxy‐3‐methyl‐but‐2‐enyl‐1‐diphosphate (HMBPP). The reaction, assimilated to a reductive dehydration, involves redox partners responsible for the formal transfer of two electrons to substrate MEcPP. The 2‐vinyl analogue of MEcPP was designed to generate conjugated species during enzyme catalysis, with the aim of providing new reactive centers to be covalently trapped by neighboring amino acid residues. The synthesized substrate analogue displayed irreversible inhibition towards IspG. Furthermore, we have shown that electron transfer occurs prior to inhibition; this might designate conjugated intermediates as probable affinity tags through covalent interaction at the catalytic site. This is the first report of an irreversible inhibitor of the IspG metalloenzyme. [ABSTRACT FROM AUTHOR]

The diastereoselective access to cyclopentanols and N,O‐dimethylcyclopentylhydroxylamines from 4‐pentenoic acid‐derived Weinreb amides is described. Based on the concomitant generation of both the nucleophilic and the electrophilic poles by hydrozirconation of the amide and the C=C double bond, the cyclisation may be tuned towards cyclopentanols or N,O‐dimethylcyclopentylhydroxylamines depending on the ring‐closure promotor. An extension to cis 3‐substituted N,O‐dimethylcyclohexylhydroxylamines is also presented. [ABSTRACT FROM AUTHOR]

Abstract: The interactions of three amphiphilic glycoligands derived from d-galacturonic acid (L1, L2 and L3) with copper (II) ions were investigated in aqueous solution and/or in aqueous-methanol media. The combination of potentiometry, UV–Vis spectrophotometry and Electron Paramagnetic Resonance (EPR) was used to determine the formation constants of the complexes and their relative structures in solution. The complexation sites were identified using electronic absorption and EPR spectroscopies. Copper complexes were obtained as square planar or square pyramidal mononuclear or dinuclear species. Solid compounds were synthesized and tested as catalysts in the autooxidation of catechols in methanol and in aqueous micellar media. Mononuclear species were found to be catalytically active in both media, whereas dinuclear ones do not show any significant catecholase activity. [ABSTRACT FROM AUTHOR]

The development of new fluorine‐containing building blocks and their efficient synthetic access is currently a challenging research field. Herein, the highly regio‐ and stereoselective addition of a large range of aldehydes onto trifluoromethylated benzofulvenes was achieved using a simple La/I2/DIBAL‐Cl system via a selective C−F bond activation process. This versatile methodology provided homodienyl alcohols bearing a terminal CF2‐alkene with potential further applications, as shown by the dehydration to the first benzofulvenes carrying a difluorovinyl group. In addition, for certain electron‐poor aldehydes, unprecedented ipso substitution of the CF3 group in a diene was observed, which, according to DFT studies, is related to the presence of the large, Lewis‐acidic lanthanum metal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Protecting-group-free synthesis of glycoconjugates. • Cycloadditions under Microwave activation. • Strong antifungal isoxazolidines obtained in good yields and few steps. • Potential use as crop-protecting agents. A straightforward synthesis of carbohydrate templated isoxazolidines is described, by reaction of unprotected glycosylhydroxylamines (operating as 1,3-dipoles) with methyl acrylate using microwave activation. Rhamno - and erythro -isoxazolidines are recognized by plant cells, resulting in a strong ROS-production as a plant immune response, and exert a high antifungal activity against Botrytis cinerea. [ABSTRACT FROM AUTHOR]

Nitromethylation of nitrones occurred efficiently in CH3NO2 in the presence of tetramethylammonium fluoride or triazabicyclodecene as promoters. The obtained adducts might be conveniently transformed into vicinal diamines. The process was extended to nitroethane and nitropropane affording mixtures of syn and anti stereoisomers with low diastereoselectivity. Comprehensive study of the addition of nitroalkanes to nitrones was conducted. The reaction proved efficient with TMAF or TBD as bases, in the presence of a large excess of R–NO2. Phase‐transfer catalysis gave also acceptable yields. Nitroethane or nitropropane afforded mixtures of isomerisable diastereomers. The reaction was applied to the synthesis of biologically relevant compounds. [ABSTRACT FROM AUTHOR]

The synthesis of the peracetylated ketonitrone 4 is described in four steps from l-sorbose. This cyclic nitrone is crystalline and proved to preferentially adopt a 4H3 conformation with all acetate groups in pseudo-axial orientation. Nitrone 4 undergoes regioselective cycloadditions with alkynes, affording tetra-O-acetyl-isoxazolines with good yields and stereoselectivities (4 : 1 to 9 : 1 diastereomeric ratio). Nitrone 4 and the obtained isoxazolines were smoothly deacetylated to produce the polyhydroxylated nitrone 5 and novel iminosugars containing an isoxazoline motif. Evaluation of their glycosidase inhibitory activity demonstrated their rather weak, but selective affinity for a variety of enzymes. [ABSTRACT FROM AUTHOR]

Synthetic analogues of the naturally occurring iminosugar homoDMDP, which feature a perfluoroalkyl group at the pseudo-anomeric position, have been synthesized from the corresponding sugar-derived cyclic aldonitrone. The new fluorinated iminosugars as well as homoDMDP and its 6-deoxy counterpart were evaluated for their inhibitory activity against a panel of glycosidases. While the replacement of the (1′,2′)-dihydroxyethyl substituent of homoDMDP with –C 4 F 9 proved detrimental for enzyme binding, introduction of a –C 3 F 7 moiety tuned the inhibitory activity spectrum selectively towards α-fucosidase and α-glucosidase from yeast. [ABSTRACT FROM AUTHOR]

Heavy metal on Lewis acid: The combination of lanthanide metals and AlCl3 has been employed for selective single C−F activation in benzofulvenes comprising an exocyclic CF3 substituent. Intermediate ϵ,ϵ-difluorinated metal-dienyl species react with a large variety of aldehydes in a highly regio- and diastereoselective fashion to afford 1,1-disubstituted indenes bearing a difluorovinyl group. These new building blocks have been further transformed through a hydrogenation-cyclization process into fluorinated heterocyclic spiro compounds. [ABSTRACT FROM AUTHOR]

Polyhydroxylated quinolizidines bearing a hydroxymethyl group at the ring junction were synthesized from a readily available l-sorbose-derived ketonitrone. Evaluated as glycoside hydrolase inhibitors, these quinolizidines revealed to be potent and selective a-glucosidase inhibitors. Quinolizidine 9a is the first quinolizidine-scaffolded iminosugar exhibiting nanomolar inhibition of a glycoenzyme. [ABSTRACT FROM AUTHOR]

An efficient (+)-camphor-mediated kinetic resolution of racemic cyclohex-2-en-1-ylalane is described. This approach provides an enantiomerically enriched form of the alane, in situ available for synthetic uses. Applied to the allylation of aldehydes, this protocol leads to the corresponding homoallylalcohols in a highly enantioselective manner. [ABSTRACT FROM AUTHOR]

The synthesis and the biological evaluation of a new ferrocenyl-iminosugar conjugate designed for fucosidase inhibitory and anticancer activity is described. The compound showed strong affinity for fucosidase from bovine kidney ( K i = 23 nM) and from Bacteroides thetaiotaomicron ( K i = 150 nM), displaying a 10-fold tighter binding affinity for these enzymes than the previous analogs. The interaction pattern that improves binding has been evaluated through structural analysis of the inhibitor–enzyme complex. The ferrocenyl-iminosugar exhibits significant anticancer activity on MDA-MB-231 and SK-MEL28 cell lines at 100 μM. [ABSTRACT FROM AUTHOR]

[4Fe-4S] enzymes, fraudulent substrates, irreversible inhibition, IspG (GcpE), MEP pathway Cover Feature: Irreversible Inhibition of IspG, a Target for the Development of New Antimicrobials, by a 2-Vinyl Analogue of its MEcPP Substrate (Chem. Eur. J. 30/2022) Keywords: [4Fe-4S] enzymes; fraudulent substrates; irreversible inhibition; IspG (GcpE); MEP pathway EN [4Fe-4S] enzymes fraudulent substrates irreversible inhibition IspG (GcpE) MEP pathway 1 1 1 05/27/22 20220525 NES 220525 B The rational design b of a substrate analogue has afforded the first irreversible inhibitor of an IspG enzyme, a target for the development of new drugs to fight antimicrobial resistance. [Extracted from the article]

Fucosidase inhibitors represent captivating targets for various biological applications. Iminosugars featuring a fluoroalkyl chain in the pseudoanomeric position were synthesized by nucleophilic addition of a perfluoroalkyl Grignard reagent to a nitrone. Reduction of the N-O bond of the hydroxylamine was achieved by treatment with an aqueous solution of sulfur dioxide. The p Ka = 4.5 of the target pyrrolidine reflected a strong electronic effect of the fluoroalkyl chain. Inhibitory potencies of the fluorinated iminosugars and their corresponding hydroxylamines were evaluated against α- L-fucosidase at various pH values. [ABSTRACT FROM AUTHOR]

A series of diastereomeric tetrahydroxylated azepanes featuring a carboxymethyl group at the pseudo-anomeric position have been synthesized from a common unsaturated intermediate. Syn - and anti -dihydroxylation reactions were achieved to yield the target compounds after efficient one-step deprotection of carbamate, ester and acetonide groups simultaneously. Screening of these polyhydroxylated azepanes toward a range of commercially available glycosidases was performed and one of the stereoisomers showed potent and selective inhibition toward β-galactosidase (IC 50 = 21 μM). [ABSTRACT FROM AUTHOR]

Ten phenylalkyl-substituted iminosugars ( 1 – 10 ) and a cinnamic acid derived glucoside ( 11 ) were isolated from the roots of Glyphaea brevis (Malvaceae). Their structures were elucidated by 1D and 2D NMR analysis, as well as by HR-ESIMS. Compounds 1 – 10 retain an unprecedented structure composed of an iminosugar-like core identified as 1-deoxyfuconojirimycin in glyphaeaside A 1 –A 4 ( 1 , 2 , 5 , 6 ), 1-deoxygalactonojirimycin in glyphaeaside B 1 –B 5 ( 3 , 4 , 7 – 9 ) or 1-deoxynojirimycin in glyphaeaside C ( 10 ), substituted by a β - d -glucopyranose in compounds 2 , 4 , 6 and 9 . These compounds feature a di-, tri- or tetra-hydroxylated nine-carbon chain at the pseudo-anomeric position, substituted by a terminal phenyl group. All alkyl C -iminosugars displayed potent and selective inhibition towards β -glucosidase with IC 50 values ranging from 0.15 to 68 μM. Compound 10 with an 1-deoxynojirimycin backbone was the most active and was found to act as a competitive inhibitor with K i = 31 nM, therefore emerging as one of the most potent inhibitor of β -glucosidase reported to date. Inhibition of β -mannosidase was observed with compounds 1 , 3 , 7 and 10 , but only weak inhibition could be detected with the alkyl- C -iminosugars on the other tested glycosidases ( α -glucosidase, α -fucosidase, α - and β -galactosidase). [ABSTRACT FROM AUTHOR]

Heterocyclic chalcones were synthesized by reaction of 4-acetylpyridine with the corresponding aromatic aldehydes under Claisen Schmidt conditions. These chalcones were used as starting material for the synthesis of oximes in the presence of hydroxylamine hydrochloride. The structures of the synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and ESI-MS, HRMS spectral analyses. All the synthesized compounds were evaluated for their antioxidant activity by DPPH• method and their in vitro antimicrobial activity by disk diffusion method against two Gram-negative bacteria, one Gram-positive bacteria and two fungal strains (C. albicans and A. niger). The results showed that the synthesized compounds did not display significant antioxidant activity. However, compounds 3b, 3d, 3f, 3h, 3i showed excellent antibacterial activity better than the standard drug against the bacterial strain S. aureus (ATCC 25923). The two compounds 3c, 3d proved very active against the fungal strain A. niger (MIC= 7.81 µg/ mL, 15.62 µg/mL respectively) while the antifungal drug used as reference (Fluconazole) was inactive. Molecular docking and molecular dynamics results revealed that the synthesized compounds, 4e, 4c , and 5j , were involved in a large number of favorable interactions with the active site residues of the acetylcholinesterase protein, which can stabilize the ligands in the active site and increase their affinities. [Display omitted] [ABSTRACT FROM AUTHOR]

Enhanced metabolism of fucose through fucosidase overexpression is a signature of some cancer types, thus suggesting that fucosidase-targetted ligands could play the role of drug-delivery vectors. Herein, we describe the synthesis of a new series of pyrrolidine-ferrocene conjugates, consisting of a L- fuco-configured dihydroxypyrrolidine as the fucosidase ligand armed with a cytotoxic ferrocenylamine moeity. Three-dimensional structures of several of these fucosidase inhibitors reveal transition-state-mimicking 3 E conformations. Elaboration with the ferrocenyl moiety results in sub-micromolar inhibitors of both bovine and bacterial fucosidases, with the 3D structure of the latter revealing electron density indicative of highly mobile alkylferrocene compounds. The best compounds show a strong antiproliferative effect, with up to 100 % inhibition of the proliferation of MDA-MB-231 cancer cells at 50 μ M. [ABSTRACT FROM AUTHOR]

Abstract: A convenient approach to the construction of dihydroxylated unsaturated azepanes featuring a functional group (ethoxycarbonyl)methyl or (cyano)methyl at C-2 was achieved from a pent-4-enal synthon obtained in four steps from d-xylose. The key step of the sequence relied on the conjugate addition of allylamine to α,β-unsaturated ester or nitrile, prepared by Wadsworth–Emmons olefination. Subsequent RCM afforded the target unsaturated azepanes. [Copyright &y& Elsevier]

The total synthesis of enantiopure 4-epi-(+)-codonopsinine was achieved in 10 steps starting from d-ribose as a chiral building block. The key step involved a highly stereoselective nucleophilic addition of a Grignard reagent to a protected ribosylamine. Synthesis of the N-desmethyl derivative and its p-tolyl analogue was also accomplished, and the compounds were assayed against a-fucosidase. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen-in-the-ring analogues of l-fucose and l-rhamnose were prepared, which feature a spirocyclopropyl moiety in place of the methyl group of the natural sugar. The synthetic route involved a titanium-mediated aminocyclopropanation of a glycononitrile as the key step. Four new spirocyclopropyl iminosugar analogues were generated, which displayed some activity towards l-fucosidase and l-rhamnosidase. [Copyright &y& Elsevier]

Abstract: The interactions between a new proline–threonine dipeptide ligand with two metallic cations were investigated in aqueous solution. The metallic cations studied were the copper(II) and the nickel(II), which are involved in many biological processes. The combination of potentiometry, UV–visible spectrophotometry, EPR, and mass spectrometry was used to determine the formation constants of the complexes and their structure in solution. The complexation sites were identified using electronic absorption and EPR spectroscopies. Copper complexes were obtained as square planar or square pyramidal mononuclear species, whereas nickel complexes were obtained as dinuclear species with an octahedral geometry. [Copyright &y& Elsevier]

The methionine salvage pathway is ubiquitous in all organisms, but metabolic variations exist between bacteria and mammals. 5-Methylthioribose (MTR) kinase is a key enzyme in methionine salvage in bacteria and the absence of a mammalian homolog suggests that it is a good target for the design of novel antibiotics, The structures of the apo-form of Bacillus subtilis MTR kinase, as well as its ADP, ADP-PO4, AMP-PCP, and AMPPCP-MTR complexes have been determined. MTR kinase has a bilobal eukaryotic protein kinase fold but exhibits a number of unique features. The protein lacks the DFG motif typically found at the beginning of the activation loop and instead coordinates magnesium via a DXE motif (Asp250-Glu252). In addition, the glycine-rich loop of the protein, analogous to the "Gly triad" in protein kinases, does not interact extensively with the nucleotide. The MTR substrate-binding site consists of Asp233 of the catalytic HGD motif, a novel twin arginine motif (Arg340/Arg341), and a semi-conserved W-loop, which appears to regulate MTR binding specificity. No lobe closure is observed for MTR kinase upon substrate binding. This is probably because the enzyme lacks the lobe closure/inducing interactions between the C-lobe of the protein and the ribosyl moiety of the nucleotide that are typically responsible for lobe closure in protein kinases. The current structures suggest that MTR kinase has a dissociative mechanism. [ABSTRACT FROM AUTHOR]

A series of 6H,7H-7-(4-Hydroxy-3-coumarinyl)[1]benzopyrano[4,3-b][1]benzopyran-6-ones 4a-g and 3-(2-hydroxybenzoyl)-2H-chromen-2-ones 5a-g derivatives were synthesized by reaction of 4-hydroxycoumarin with 2-hydroxyarylaldehydes 2a-f or 2-hydroxynaphtaldehyde 2g using different solvents and acid/base catalysts. The approach relies on a regioselective cascade reaction involving one/two molar equiv of the 4-hydroxy coumarin iteratively acting as active methylene substrate in a Knoevenagel condensation and in a Michael addition. The structures of all compounds were established by IR, mass spectrometry, 1H-NMR and 13C-NMR. Antioxidant activity of the synthesized compounds were determined using the DPPH scavenging assay, best results being obtained with 5b (IC 50 = 236 µg/mL). Computational studies showed that the compounds bind in the ATP-binding site of p38 MAPK, in a same manner than known polyaromatic potent inhibitors. The synthesized compounds might be considered further for cancer therapy. Image, graphical abstract [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of a chromogenic analogue of myo -inositol hexaphosphate. • Amenable to g-scale. • Docking experiments confirmed the compatibility with the active site of phytases. • Phytases operate experimentally with this fluorogenic substrate. A new myo -inositol pentakisphosphate was synthesized, which featured a dansyl group at position C-5. The fluorescent tag was removed from the inositol by a 6-atom spacer to prevent detrimental steric interactions in the catalytic site of phytases. The PEG linker was used in order to enhance hydrophilicity and biocompatibility of the new artificial substrate. Computational studies showed a favorable positioning in the catalytic site of phytases. Enzymatic assays demonstrated that the tethered myo -inositol was processed by two recombinant phytases Phy-A and Phy-C, classified respectively as acid and alkaline phytases, with similar rates of phosphate release compared to their natural substrate. [ABSTRACT FROM AUTHOR]

A diagram is presented which explains the chemical process of Perfluoroalkylation of Nitrones for the Synthesis of a Series of Fucosidase Inhibitors.

Key steps in the synthesis of azepanes (VIII) and (X), which are of interest as glycosidase inhibitors, are the conjugate addition of allylamine to the precursor (III) and final ring-closing metathesis with the pure diastereomers (VII) and (IX). [ABSTRACT FROM AUTHOR]