Aldehyde Fragment Research Articles

Ursolic acid-based 24-nor- and A-seco-24-oxy-triterpenoids

Using methyl 2-cyano-3,4-seco-12(13),4(23)-diene-ursolate as a starting scaffold the synthesis of 3-oxo-24-nor-ursolate and A-seco-ursanes holding hydroxy-, furoyloxy-, p-tosyloxy- as well as aldehyde fragments at C24 that possess cytotoxic activity have been synthesised. The structures of the new ursanes were confirmed by detailed spectral data analysis. The chemoselectivity of methyl 2-cyano-3,4-seco-12(13),4(23)-diene-ursolate oxidation involving the double bond in the A cycle was observed.

Two phenanthro[9,10-d]imidazole-based fluorescence probes for distinguishable detection of Cys and Fe3+ and their applications in food and water as well as living cells monitoring

Accurately designing and developing the dual responsive fluorescence probe with simultaneous recognition of intracellular biothiols and metal ions is of great significance. Here, we reported two phenanthrene[9,10-d]imidazole derivatives (PIP-CHO and NO2-PIP-CHO) modified with aldehyde fragment as chemosensor for synchronous detection of Cys and Fe3+. PIP-CHO and NO2-PIP-CHO performed the hydrophilic nature despite the fact that they possessed the distinct aggregation behavior with the increasing of water contents. In aqueous medium (water/DMF), PIP-CHO predominantly exhibited high sensitivity and selectivity for “on–off” fluorescent recognition of Fe3+ with a limit of detection (LOD) of 213.74 nmol·L–1, and Cys with a LOD of 116.66 nmol·L–1, respectively. Correspondingly, the detection limits of NO2-PIP-CHO toward Fe3+ and Cys were calculated in DMF as 347.68 and 215.64 nmol·L–1, respectively. The fluorescent recognition mechanism of cycloaddition and coordination for PIP-CHO with Cys and Fe3+ was rationally explained by SEM, 1H NMR and ESI-MS, respectively. Noteworthy, the naked-eye strips encompassing PIP-CHO enabled distinguishable visualization of Cys and Fe3+ with the color change under visible or UV light. In addition, PIP-CHO can be successfully applied to detect Cys and Fe3+ in food and water samples by fluorescence method, as well as the living Yeast cells via fluorescence dual channel.

Chiral Bis(8-Quinolyl)Ethane-Derived Diimine: Structure Elucidation and Catalytic Performance in Asymmetric Synthesis of (S)-Warfarin

C2-symmetric diimine generated in situ from (R,R)-HPEN and 8-formylquinoline was readily transformed to novel chiral diimine pre-III bearing 1(S),2(S)-bis(quinolin-8-yl) ethane and salicylic aldehyde fragments via stereoselective diaza-Cope rearrangement. The structure and absolute configuration of the product was established by the X-ray diffraction study of the corresponding Rh(III) complex. In the presence of pre-III, practically important enantioselective reactions of 4-hydroxycoumarin with α,β-enones afforded anticoagulant (S)-warfarin and its derivatives in aqueous THF in high yield (88–92%) with enantioselectivity 85–93% ee.

Synthesis and In Silico Prediction of Biological Activity and Acute Toxicity of [1,3]Thiazolo[3,2-a]pyrimidines Containing Aliphatic Aldehyde Fragments

Synthesis and In Silico Prediction of Biological Activity and Acute Toxicity of [1,3]Thiazolo[3,2-a]pyrimidines Containing Aliphatic Aldehyde Fragments

Iridoids and sesquiterpenoids from Valeriana jatamansi and their anti-influenza virus activities

Twenty-one new iridoids, jatamansidoids A-U (1–12, 21–26, 32, 35 and 36), two new natural ones, jatamansidoids V (37) and W (38), eighteen known ones (13–20, 27–31, 33 and 34), together with three patchoulol-type sesquiterpenoids (39–41), were isolated from the roots and rhizomes of Valeriana jatamansi. Structurally, compounds 1–7 were the first examples of iridoids from V. jatamansi with unique α, β, γ, δ-unsaturated aldehyde fragment between C-11, C-4, C-5, C-9 and C-8; compound 8 was an unprecedented iridoid derivative with a methyl group (Me-10) at C-1, rather than C-8, and its plausible biogenetic pathway was proposed in this paper; compounds 22 and 23 were the first examples of Δ4(5)-iridoids simultaneously replaced by oxygen-containing groups at C-3, C-6 and C-7; compound 24 was the first iridoid with both 6,7- and 1,10-epoxy fragments. The structures and absolute configurations of new compounds were elucidated based on extensive spectroscopic techniques and quantum chemical calculation. Furthermore, compounds 13–15 and 39–41 exhibited potent anti-influenza virus activities with H1N1 and H3N2 strains, with IC50 values of 0.21–1.48 µM.

Stereoselective Synthesis of the C19–C39 Fragment of Bastimolide A

AbstractThis paper describes the synthesis of the C19–C39 fragment of the antimalarial natural product bastimolide A via addition of a functionalized C19–C26 alkyne fragment to a C27–C39 aldehyde fragment. Opening of a terminal epoxide and Noyori asymmetric reduction were used as key steps in the synthesis.

Lipid Peroxide-Derived Short-Chain Aldehydes are Involved in Aluminum Toxicity of Wheat (Triticum aestivum) Roots.

Lipid peroxidation is a common event during aluminum (Al) toxicity in plants, and it generates an array of aldehyde fragments. The present study investigated and compared the profile and physiological functions of lipid peroxide-derived aldehydes under Al stress in two wheat genotypes that differed in Al resistance. Under Al stress, the sensitive genotype Yangmai-5 suffered more severe plasma membrane damage and accumulated higher levels of aldehydes in roots than the Al-tolerant genotype Jian-864. The complementary use of high-resolution mass spectrometry and standard compounds allowed the identification and quantification of 13 kinds of short-chain aldehydes sourced from lipids in wheat roots. Among these aldehydes, acetaldehyde, isovaldehyde, valeraldehyde, (E)-2-hexenal (HE), heptaldehyde, and nonyl aldehyde were the predominant species. Moreover, it was found that HE in the sensitive genotype was over 2.63 times higher than that in the tolerant genotype after Al treatment. Elimination of aldehydes using carnosine rescued root growth inhibition by 19.59 and 11.63% in Jian-864 and Yangmai-5, respectively, and alleviated Al-induced membrane damage and protein oxidation. Exogenous aldehyde application further inhibited root elongation and exacerbated oxidative injury. The tolerant genotype Jian-864 showed elevated aldehyde detoxifying enzyme activity and transcript levels. These results suggest that lipid peroxide-derived short-chain aldehydes are involved in Al toxicity, and a higher aldehyde-detoxifying capacity may be responsible for Al tolerance.

Synthesis and Bioevaluation of 5-Chloro-4-(1,3-Oxazol-5-yl)-1Н-Pyrrole-3-Carboxyamides as Antimicrobial Agents

This investigation deals with the design and synthesis of new derivatives of pyrrole consisting of modifying atoms of chlorine, amide, and 1,3-oxazole fragments. These compounds can be interesting in the context of research of new antimicrobial agents. Ethyl 5-chloro-4-formyl-1H-pyrrole-3-carboxylates were used as a key substrate for further transformation into target compounds. This process was realized as a direct transformation of an aldehyde fragment into a 1,3-oxazole cycle by van Leusen’s reaction followed by hydrolysis of an ester group, which finally converted a reactant into the corresponding pyrrole-3-carboxylic acid. This acid has been found to be an efficient construction block for the further development of antimicrobial agents. The preparative potential of these compounds has been verified by way of their transformation into a series of carbamides through consecutive reactions with thionyl chloride and alkyl-, aryl, and heterylamines under mild reaction conditions. According to bio screening results, the following two compounds have been chosen as those exhibiting a high anti-staphylococcus activity: 1-butyl-5-chloro-2-methyl-4-(1,3-oxazol-5-yl)-N-[(1,3-thiazol-2-yl]-1H-pyrrole-3-carboxamide and 1-butyl-5-chloro-N-[(3-dimethylaminosulfonyl)phenyl]-2-methyl-4-(1,3-oxazol-5-yl)-1H-pyrrole-3-carboxamide (МІС=7.8 µg/ml), while another one – 5-сhloro-N-(4-chlorophenyl)-4-(1,3-oxazol-5-yl)-2-phenyl-1-propyl-1H-pyrrole-3-carboxamide was selected as a compound exhibiting high antifungal activity (МІС=7.8 µg/ml) against the reference strains Candida albiсans АТСС 885/653 and Aspergillus niger K9.

SYNTHESIS AND ANTIPROLIFERATIVE ACTIVITY OF SALICYLIDENEHYDRAZONES BASED ON INDOLE-2(3)-CARBOXYLIC ACIDS

A series of indole-2(3)-carboxylic acid hydrazones were synthesized and their antiproliferative activity was studied for the K562 leukemia, MCF7 breast adenocarcinoma, and HCT116 colon carcinoma cell lines and resistant HCT116p53KO subline in order to preliminary screen biological properties and to reveal the role of the aldehyde fragment and heterocycle in the ability of compounds to inhibit tumor growth. A number of derivatives have been identified that inhibit the growth of tumor cells in submicromolar concentrations, promising for further optimization and in-depth study of antitumor properties.

Synthesis and antiproliferative activity of salicylidenehydrazones based on indole-2(3)-carboxylic acids

A series of indole-2(3)-carboxylic acid hydrazones were synthesized and their antiproliferative activity was studied for the K562 leukemia, MCF7 breast adenocarcinoma, and HCT116 colon carcinoma cell lines and resistant HCT116p53KO subline in order to preliminary screen biological properties and to reveal the role of the aldehyde fragment and heterocycle in the ability of compounds to inhibit tumor growth. A number of derivatives have been identified that inhibit the growth of tumor cells in submicromolar concentrations, promising for further optimization and in-depth study of antitumor properties.

Synthesis and Structure-Activity Relationship Studies of Hydrazide-Hydrazones as Inhibitors of Laccase from Trametes versicolor.

A series of hydrazide-hydrazones 1–3, the imine derivatives of hydrazides and aldehydes bearing benzene rings, were screened as inhibitors of laccase from Trametes versicolor. Laccase is a copper-containing enzyme which inhibition might prevent or reduce the activity of the plant pathogens that produce it in various biochemical processes. The kinetic and molecular modeling studies were performed and for selected compounds, the docking results were discussed. Seven 4-hydroxybenzhydrazide (4-HBAH) derivatives exhibited micromolar activity Ki = 24–674 µM with the predicted and desirable competitive type of inhibition. The structure–activity relationship (SAR) analysis revealed that a slim salicylic aldehyde framework had a pivotal role in stabilization of the molecules near the substrate docking site. Furthermore, the presence of phenyl and bulky tert-butyl substituents in position 3 in salicylic aldehyde fragment favored strong interaction with the substrate-binding pocket in laccase. Both 3- and 4-HBAH derivatives containing larger 3-tert-butyl-5-methyl- or 3,5-di-tert-butyl-2-hydroxy-benzylidene unit, did not bind to the active site of laccase and, interestingly, acted as non-competitive (Ki = 32.0 µM) or uncompetitive (Ki = 17.9 µM) inhibitors, respectively. From the easily available laccase inhibitors only sodium azide, harmful to environment and non-specific, was over 6 times more active than the above compounds.

SYNTHESIS, STRUCTURE OF MONO- AND BINUCLEAR COMPLEXES OF Sn(IV) WITH DIHYDRAZONES OF AROMATIC ALDEHYDES

By interaction of SnCl 4 with condensation products of dihydrazides of oxalic, terephthalic, malonic acids and R-benzoic aldehydes (R = Н, 4-N(CH 3 ) 2 , 2-OH) in acetonitrile, the following complexes were synthesized: with oxaloyl- [SnCl 4 (H 2 Oxb)]∙CH 3 CN (R = Н, I ), [SnCl 4 (Oxdb∙2H)]·2CH 3 CN (R = 4-N(CH 3 ) 2 , II ), [SnCl 4 (H 4 Oxs)]∙CH 3 CN (R = 2-OH, III ), терефталоїл- [(SnCl 4 )2(μ-Tfdb·2H)]∙2CH 3 CN (R = 4-N(CH 3 ) 2 , IV ), [SnCl 4 (μ-H 2 Tfs)]∙CH 3 CN (R = 2-OH, V ), malonoyldihydrazones- [SnCl 4 (μ-Maldb·2H)]·2CH 3 CN (R = 4-N(CH 3 ) 2 , VI ), [SnCl 4 (μ-H 2 Mals)] ∙ CH 3 CN (R = 2-OH, VII ). Their composition and structure are established by the methods of elemental analysis, conductometry, thermogravimetry, and IR spectroscopy. It was established that in the absence of a spacer (X = 0) in the dihydrazone molecules of R-benzoic aldehydes (R = H, 2-OH, 4-N(CH 3 ) 2 ) – oxaloyl dihydrazones, regardless of the presence of functional groups (CН=N, OH) as part of these molecules, SnCl 4 forms only mononuclear complexes I-III with the same O,O- coordination and composition of the coordination node, the charge of which is determined by a substituent (R) in the aldehyde fragment: R = H, 2-OH – {SnCl 4 O 2 }, R = 4-N(CH 3 ) 2 – {SnCl 4 O 2 } 2- . In the presence of a spacer in dihydrazone molecules, regardless of their stereochemical rigidity (X = -C 6 H 4 -, -CH 2 -), only if R = 2-OH, 4-N(CH 3 ) 2 , binuclear Sn(IV) complexes are formed with spatially separated coordination nodes, the composition of the nodes and the dihydrazone denatism is been determined by the substituent (R): R = 4-N(CH 3 ) 2 – {SnCl 4 ON} 2 - (tetra- in IV, VI ), R = 2-OH – {SnCl 3 O 2 N} (hexacoordinated ligand in V, VII ). Coordination of dihydrazones in a enol form, both in mono- ( II ) and in binuclear complexes ( IV, VI ), is a consequence of the presence of vacant nitrogen atoms in the aldehyde fragments of their molecules (R = 4-N(CH3)2); due to their protonation, a negative charge is compensated, which is localized in this case at the coordination sites of the zwitterionic complexes {SnCl 4 O 2 } 2- ( II ) and {SnCl 4 ON} 2- ( IV , VI ). The patterns of the formation of each spatially separated coordination node and the tautomeric form of the ligands in IV-VII are the same as in mononuclear tin(IV) complexes.

Synthesis of New Photochromic Dithienylmaleimides with Acetal and Aldehyde Fragments

Reaction of 3,4-dithienylmaleic anhydrides with aminoacetaldehyde dimethylacetal results in the formation of 3,4-dithienyl-substituted 1-(2,2-dimethoxyethyl)-1H-pyrrole-2,5-diones. The hydrolysis of the latter in acid medium results in the preparation of 2-[3,4-bis(thienyl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl]-acetaldehydes. The obtained functionalized derivatives of maleimide demonstrate photochromic properties in solution.

Conformational control over an aldehyde fragment by selective vibrational excitation of interchangeable remote antennas.

We apply interchangeable vibrational antennas (OH or NH2 group) to achieve unprecedented conformational control over the heavy aldehyde fragment in 2-formyl-2H-azirine. The two aldehyde conformers were manipulated bi-directionally, using selective vibrational excitation with narrowband near-infrared (NIR) light tuned at the wavenumbers corresponding to OH and NH2 stretching overtones and combination modes.

Radical Generation from the Gas-Phase Activation of Ionized Lipid Ozonides

Reaction products from the ozonolysis of unsaturated lipids at gas–liquid interfaces have the potential to significantly influence the chemical and physical properties of organic aerosols in the atmosphere. In this study, the gas-phase dissociation behavior of lipid secondary ozonides is investigated using ion-trap mass spectrometry. Secondary ozonides were formed by reaction between a thin film of unsaturated lipids (fatty acid methyl esters or phospholipids) with ozone before being transferred to the gas phase as [M + Na]+ ions by electrospray ionization. Activation of the ionized ozonides was performed by either energetic collisions with helium buffer-gas or laser photolysis, with both processes yielding similar product distributions. Products arising from the decomposition of the ozonides were characterized by their mass-to-charge ratio and subsequent ion-molecule reactions. Product assignments were rationalized as arising from initial homolysis of the ozonide oxygen–oxygen bond with subsequent decomposition of the nascent biradical intermediate. In addition to classic aldehyde and carbonyl oxide-type fragments, carbon-centered radicals were identified with a number of decomposition pathways that indicated facile unimolecular radical migration. These findings reveal that photoactivation of secondary ozonides formed by the reaction of aerosol-bound lipids with tropospheric ozone may initiate radical-mediated chemistry within the particle resulting in surface modification.Graphical ᅟ

Syngas to Chemicals: The Incorporation of Aldehydes into Fischer–Tropsch Synthesis

AbstractSyngas is an important intermediate for the synthesis of chemicals and fuels; it can be produced from renewable and fossil feedstocks. Syngas conversion on Fe catalysts results mostly in linear paraffins, olefins, and oxygenates. In the produced olefins or oxygenates, the functional groups or double bonds are always located in the hydrocarbon α‐position. The yield of nonlinear functionalized hydrocarbons or chemical compounds with secondary and tertiary functional groups is low. In this paper direct synthesis of diverse functionalized and branched hydrocarbons in the Fischer–Tropsch reaction is explored by the cofeeding aldehydes to syngas; the added aldehydes initiate surface polymerization. Quantitative stoichiometric incorporation of aldehydes in the growing hydrocarbon chain was observed. The hydrocarbons that contain incorporated aldehyde fragments exhibit an Anderson–Schulz–Flory distribution similar to that from conventional Fischer–Tropsch synthesis.

Total Synthesis of Resolvin D5.

Resolvin D5 (RvD5) is a metabolite of docosahexanoic acid with anti-inflammatory activity that has not yet been thoroughly investigated because of its low biological availability. A synthetic route to optically active RvD5 was developed by assembling the C1-C10 aldehyde, C11-C13 phosphonium salt, and C14-C22 aldehyde building blocks. The aldehyde fragments were prepared by Sharpless asymmetric epoxidation of corresponding racemic (E)-1-TMS-1-alken-3-ols followed by reaction of the TBS ethers of the resulting epoxy alcohols with Et2AlCN and DIBAL reduction of the (E)-1-cyano-1-alken-3-ol derivatives. The C14-C22 aldehyde was connected with the C11-C13 fragment, i.e., [TBSO(CH2)3PPh3]+ Br-, by Wittig reaction. The resulting C11-C22 intermediate was converted to the phosphonium salt, which was attached to the C1-C10 aldehyde by Wittig reaction to yield the structure of RvD5.

Synthesis and biological evaluation of histamine Schiff bases as carbonic anhydrase I, II, IV, VII, and IX activators

A series of 20 histamine Schiff base was synthesised by reaction of histamine, a well known carbonic anhydrase (CA, E.C 4.2.2.1.) activator pharmacophore, with substituted aldehydes. The obtained histamine Schiff bases were assayed as activators of five selected human (h) CA isozymes, the cytosolic hCA I, hCA II, and hCA VII, the membrane-anchored hCA IV and transmembrane hCA IX. Some of these compounds showed efficient activity (in the nanomolar range) against the cytosolic isoform hCA VII, which is a key CA enzyme involved in brain metabolism. Moderate activity was observed against hCA I and hCA IV (in the nanomolar to low micromolar range). The structure–activity relationship for activation of these isoforms with the new histamine Schiff bases is discussed in detail based on the nature of the aliphatic, aromatic, or heterocyclic moiety present in the aldehyde fragment of the molecule, which may participate in diverse interactions with amino acid residues at the entrance of the active site, where activators bind, and which is the most variable part among the different CA isoforms.

On the Origin of Dolabriferol: Total Synthesis via Its Putative Contiguous Precursor.

The putative contiguous polypropionate precursor of dolabriferol was synthesized using as the key step a rationally designed enantiomer-selective aldol coupling (i.e., with kinetic resolution) of a racemic C1-C8 ketone fragment with an enantiopure C9-C15 aldehyde fragment. When exposed to alumina, the precursor was cleanly transformed into dolabriferol via a regioselective retro-Claisen fragmentation, providing the first experimental evidence for the proposed origin of dolabriferol and demonstrating that it is a plausible isolation artifact.

Preparation of conjugated dienoates with Bestmann ylide: Towards the synthesis of zampanolide and dactylolide using a facile linchpin approach.

Bestmann ylide [(triphenylphosphoranylidene)ketene] acts as a chemical linchpin that links nucleophilic entities, such as alcohols or amines, with carbonyl moieties to produce unsaturated esters and amides, respectively. In this work, the formation of α,β,γ,δ-unsaturated esters (dienoates) is achieved through the coupling of Bestmann ylide, an alcohol and an α,β-unsaturated aldehyde. Primary and secondary alcohols, including allylic alcohols, are suitable substrates; the newly formed alkene has an E-geometry. Strategically, this represents a highly efficient route to unsaturated polyketide derivatives. A linchpin approach to the synthesis of a major fragment of the natural products zampanolide and dactylolide is investigated using Bestmann ylide to link the C16–C20 alcohol with the C3–C8 aldehyde fragment.