Alcohol Moiety Research Articles

Doubly Dynamic Hydrogel Formed by Combining Boronate Ester and Acylhydrazone Bonds.

The incorporation of double dynamic bonds into hydrogels provides an effective strategy to engineer their performance on demand. Herein, novel hydrogels were PREPARED by combining two kinetically distinct dynamic covalent bonds, boronate ester and acylhydrazone bonds, and the synergistic properties of the hydrogels were studied comprehensively. The functional diblock copolymers P(N-isopropyl acrylamide-co-N-acryloyl-3-aminophenylboronic acid)-b-(N-isopropyl acrylamide-co-diacetone acrylamide) (PAD) were prepared via reversible addition−fragmentation chain transfer (RAFT) polymerization. The hydrogel was constructed by exploiting dynamic reaction of phenyboronic acid moieties with polyvinyl alcohol (PVA) and ketone moieties with adipic dihydrazide (ADH) without any catalyst. The active boronate ester linkage endows the hydrogel with fast gelation kinetics and self-healing ability, and the stable acylhydrazone linkage can enhance the mechanical property of the hydrogel. The difference in kinetics endows that the contribution of each linkage to mechanical strength of the hydrogel can be accurately estimated. Moreover, the mechanical property of the hydrogel can be readily engineered by changing the composition and solid content, as well as by controlling the formation or dissociation of the dynamic linkages. Thus, we provide a promising strategy to design and prepare multi-responsive hydrogels with tunable properties.

Applications of Bolm's Ligand in Enantioselective Synthesis.

One pathway for the preparation of enantiomerically pure compounds from prochiral substrates is the use of metal complex catalysis with chiral ligands. Compared to the other frequently used chiral ligands, chiral 2,2′-bipyridines have been underexploited, despite the data indicating that such ligands have considerable potential in synthetic chemistry. One of those is the so-called Bolm’s ligand, a compound possessing chiral alcohol moieties in the side chains attached to the 2,2′-bipyridine scaffold. Various metal salts have been used in combination with Bolm’s ligand as potent catalysts able to bring about enantioselective alkylations, allylations, conjugate additions, desymmetrization of meso-epoxides, aldol reactions, etc. This review aims to summarize Bolm’s ligand applications in the area of enantioselective synthesis over the last three decades since its preparation.

Partial sequence isolation of DXS and AOS genes and gene expression analysis of terpenoids and pyrethrin biosynthetic pathway of Chrysanthemum cinerariaefolium under abiotic elicitation

One of the most important issues in crop production is the use of agrochemicals. The use of synthetic or manufactured chemicals on crops has made a frightening image of health problems. A concern about chemical residues on food products has led to seek for new alternative compounds with fewer side effects on humans and environment. Pyrethrum (Chrysanthemum cinerariaefolium) belongs to the Asteraceae family is one of the most important resources of natural insecticides which produce pyrethrin I. Pyrethrin I has an acidic moiety and an alcohol moiety, the acidic moiety of these molecules is a monoterpene with a cyclopropane ring and biosynthesized via 2-C-methylerythrol 4-phosphate pathway (MEP) and alcohol moiety is biosynthesized via the lipoxygenase pathway through membrane lipids. At the end, the acidic moiety and alcohol moiety from separate pathways conjugate together by TcGLIP enzyme, a kind of GLIP lipase family. Based on the importance of pyrethrin I as a natural insecticide in pyrethrum partial sequences of 1-deoxy d-xylulose 5-phosphate synthase (DXS) gene from the MEP pathway and Allene oxide synthase (AOS) gene from the lipoxygenase pathway were isolated by specific primers to study their expression patterns in different conditions. Along with this, gene expression patterns of DXS, chrysanthemyl diphosphate synthase, farnesyl diphosphate synthase, GLIP lipase (TcGLIP), AOS and 13-lipoxygenase were investigated under abiotic elicitors including trans-cinnamic acid, methyl jasmonate, salicylic acid and ultra-violet ray by RT-PCR to determine the effect of aforementioned elicitors on transcript levels. Results showed that the expression of genes in the biosynthetic pathway of pyrethrin I under methyl-jasmonate, salicylic acid and ultra-violet ray treatments were up-regulated in compared with control plants.

Biomimetic Oxidation of Monolignol Acetate and p-Coumarate by Silver Oxide in 1,4-Dioxane.

Lignin acylated with acetate and/or p-coumarate is common in many herbaceous plants. Herein, the biomimetic oxidation of γ-acylated monolignols with Ag2O was studied to understand the effect of γ-acyl groups on monolignol polymerization. The oxidation of sinapyl acetate gave γ-acylated and α-acylated β-O-4 dimers in 71 and 9.5% yields, respectively. The oxidation of sinapyl p-coumarate produced γ-acylated β-O-4 and γ-acylated tetralin β-β dimers in 53 and 16% yields, respectively. Only the sinapyl alcohol moiety in sinapyl p-coumarate reacted, and the p-coumarate moiety remained unchanged, suggesting that p-coumaric acid is not incorporated into the lignin backbone in the acylated lignins. All of the γ-acylated monolignols used in this study produced the γ-acylated β-O-4 dimers, which suggests that the γ-acylated monolignols act as lignin monomers. The relatively high yields of the β-O-4 dimers indicate that Ag2O oxidation of the monolignols can be used as an easy method for synthesizing the β-O-4 dimer model compounds.

Synthesis and antiproliferative effect of the proposed stereoisomer of the marine sponge metabolite halisphingosine A.

The first synthesis of the proposed natural stereoisomer of halisphingosine A, a metabolite of the marine sponge Haliclona tubifera, was accomplished in 11 steps including an enantioselective Henry reaction, a Weinreb amide - acetylide coupling, and stereoselective reductions of the resulting ynone to afford the R,Z-configured allyl alcohol moiety. The synthetic product differed from the natural isolate in some 13C-NMR data. It showed antiproliferative activity at clinically relevant concentrations against six tumour cell lines including such lacking functional tumor suppressor gene p53.

Catalytic enantioselective domino Michael/transannular aldol reaction under bifunctional catalysis.

The enantioselective Michael reaction catalyzed by a bifunctional tertiary amine/squaramide has been used to trigger a Michael/transannular aldol cascade process that leads to densely substituted bicyclo[5.4.0]undecanes and in which three contiguous stereogenic centres, one of them a tertiary alcohol moiety, have been formed in a fully stereocontrolled fashion.

Caryophyllene sesquiterpenes, chromones and 10-membered macrolides from the marine-derived fungus Pseudopestalotiopsis sp. PSU-AMF45

Three new caryophyllene sesquiterpenes, pestalotiopsins I–K, one new chromone, pseudopestalone, and one new 10-membered macrolide, decarestrictine Q, were isolated from the fermentation broth of the marine-derived fungus Pseudopestalotiopsis sp. PSU-AMF45 along with twelve known compounds. Their structures were identified by spectroscopic data including 1D and 2D NMR. The absolute configuration of pestalotiopsin I was assigned based on single-crystal X-ray diffraction crystallography whereas that of the secondary alcohol moiety in pestalotiopsin J was established by Mosher's method. For pseudopestalone, the absolute configuration was determined by ECD spectrum associated with TD-DFT calculation. The antimicrobial activity of the isolated compounds was evaluated.

Dissolved organic matter extracted from groundwater and heavy metals behavior in Ain Senan-Kef, Tunisia

In this study, dissolved organic matter (DOM) extracted from Tunisian water was examined using elemental analysis, size exclusion chromatography, nuclear magnetic resonance spectroscopy, pyrolysis gas chromatography-mass spectrometry and fluorescence spectroscopy. DOM has been quantified with parameters including ultraviolet–visible, total organic carbon, chemical oxygen demand and specific UV-absorbance. Elemental analysis indicated that groundwater contained a high amount of oxygen but a low amount of carbon. Based on fluorescence indices, organic matter is dominated by biological/autochthonous species, which are typically observed in the waters. The use of GC/MS revealed the presence of proteins. The interactions of heavy metals (Hg, Zn and Cu) with DOM have been studied using X-ray diffraction, ICP-AES, Fluorescence and FTIR spectroscopies. Zn appears to be bound to humic acid primarily through carboxyl-functional groups, while Hg ions apparently are bound through carboxylic, phenolic and alcoholic moieties. Cu (II) is bound preferentially to oxygen and nitrogen containing functional groups. Organic matter was supposed to be organomineral complexes.

Synthesis, molecular docking, and biological evaluation of 3-oxo-2-tolylhydrazinylidene-4,4,4-trifluorobutanoates bearing higher and natural alcohol moieties as new selective carboxylesterase inhibitors

To search for effective and selective inhibitors of carboxylesterase (CES), a series of 3-oxo-2-tolylhydrazinylidene-4,4,4-trifluorobutanoates bearing higher or natural alcohol moieties was synthesized via pre-transesterification of ethyl trifluoroacetylacetate with alcohols to isolate transesterificated oxoesters as lithium salts, which were then subjected to azo coupling with tolyldiazonium chloride. Inhibitory activity against porcine liver CES, along with two structurally related serine hydrolases, acetylcholinesterase and butyrylcholinesterase, were investigated using enzyme kinetics and molecular docking. Kinetics studies demonstrated that the tested keto-esters are reversible and selective mixed-type CES inhibitors. Analysis of X-ray crystallographic data together with our IR and NMR spectra and QM calculations indicated that the Z-isomers were the most stable. The kinetic data were well explained by the molecular docking results of the Z-isomers, which showed specific binding of the compounds in the CES catalytic active site with carbonyl oxygen atoms in the oxyanion hole and non-specific binding outside it. Some compounds were studied as inhibitors of the main human isozymes involved in biotransformation of ester-containing drugs, hCES1 and hCES2. Esters of geraniol (3d) and adamantol (3e) proved to be highly active and selective inhibitors of hCES2, inhibiting the enzyme in the nanomolar range, whereas esters of borneol (3f) and isoborneol (3g) were more active and selective against hCES1. Computational ADMET studies revealed that all test compounds had excellent intestinal absorption, medium blood-brain barrier permeability, and low hERG liability risks. Moreover, all test compounds possessed radical-scavenging properties and low acute toxicity. Overall, the results indicate that members of this novel series of esters have the potential to be good candidates as hCES1 or hCES2 inhibitors for biomedicinal applications.

Terbium(III) Luminescence-Based Assay for Esterase Activity

Esterases catalyze the hydrolysis of esters to form a carboxylic acid and alcohol. These enzymes play a key role in both the detoxification of xenobiotic compounds and the metabolism of drugs and prodrugs. Numerous fluorogenic probes have been developed to monitor esterase activity. Most are based on an aromatic alcohol, and the others are based on an aromatic acid. These restrictions leave unexplored the specificity of esterases for aliphatic esters. Here, we report on the use of esters of thiopheneacetic acid coupled with the luminescence of terbium(III) as the basis for a continuous assay of esterase activity. This probe allows for a wide variation of the alcohol moiety and the detection of its hydrolysis at submicromolar concentrations. The assay verifies steady-state kinetic parameters for catalysis by pig liver esterase from either initial rates or the integration of progress curves, and its utility is evident with unpurified esterases in bacterial and human cell lysates.

Rhodium(I)‐Catalyzed Enantioselective Cyclization of Enynes by Intramolecular Cleavage of the Rh−C Bond by a Tethered Hydroxy Group

AbstractRhodium(I)‐catalyzed enantioselective intramolecular cyclization of enynes having a hydroxy group in the tether was investigated, and various cyclic compounds possessing a chiral quaternary carbon center were obtained in high yields with high ees. In this cyclization, a Rh−C(sp2) bond in the rhodacyclopentene intermediate, which was formed by enantioselective oxidative cycloaddition of enynes to a chiral rhodium(I) complex, was intramolecularly cleaved by σ‐bond metathesis of a tethered O−H bond in the substrate. Furthermore, it was found that the cyclic compounds were obtained with high ees even when the starting materials having a racemic secondary alcohol moiety were used in this reaction.

Rhodium(I)-Catalyzed Enantioselective Cyclization of Enynes by Intramolecular Cleavage of the Rh-C Bond by a Tethered Hydroxy Group.

Rhodium(I)-catalyzed enantioselective intramolecular cyclization of enynes having a hydroxy group in the tether was investigated, and various cyclic compounds possessing a chiral quaternary carbon center were obtained in high yields with high ees. In this cyclization, a Rh-C(sp2 ) bond in the rhodacyclopentene intermediate, which was formed by enantioselective oxidative cycloaddition of enynes to a chiral rhodium(I) complex, was intramolecularly cleaved by σ-bond metathesis of a tethered O-H bond in the substrate. Furthermore, it was found that the cyclic compounds were obtained with high ees even when the starting materials having a racemic secondary alcohol moiety were used in this reaction.

Parahydrogen-Induced Polarization of 1-13C-Acetates and 1-13C-Pyruvates Using Sidearm Hydrogenation of Vinyl, Allyl, and Propargyl Esters.

13C-hyperpolarized carboxylates, such as pyruvate and acetate, are emerging molecular contrast agents for MRI visualization of various diseases, including cancer. Here we present a systematic study of 1H and 13C parahydrogen-induced polarization of acetate and pyruvate esters with ethyl, propyl and allyl alcoholic moieties. It was found that allyl pyruvate is the most efficiently hyperpolarized compound from those under study, yielding 21% and 5.4% polarization of 1H and 13C nuclei, respectively, in CD3OD solutions. Allyl pyruvate and ethyl acetate were also hyperpolarized in aqueous phase using homogeneous hydrogenation with parahydrogen over water-soluble rhodium catalyst. 13C polarization of 0.82% and 2.1% was obtained for allyl pyruvate and ethyl acetate, respectively. 13C-hyperpolarized methanolic and aqueous solutions of allyl pyruvate and ethyl acetate were employed for in vitro MRI visualization, demonstrating the prospects for translation of the presented approach to biomedical in vivo studies.

Mild Redox-Neutral Depolymerization of Lignin with a Binuclear Rh Complex in Water

A mild redox-neutral lignin depolymerization system featuring a water-soluble binuclear Rh complex has been developed. The catalytic system could be successfully applied to the depolymerization of a lignin-like polymer, alkaline lignin, as well as raw lignocellulose samples to produce aromatic ketones, providing a homogeneous catalytic system for “lignin-first” biorefinery in water. Mechanistic studies on the model substrate suggest that the reaction proceeds via a metal-catalyzed dehydrogenation step to afford a carbonyl intermediate, followed by C–O bond cleavage to afford ketone and phenol products. Deuterium labeling study shows that the hydrogen used for cleavage of the C–O bond originates from the alcohol moiety in the substrate.

Distribution of methyl and isopropyl N-methylanthranilates and their metabolites in organs of rats treated with these two essential-oil constituents

Two volatile alkaloids, methyl (MMA) and isopropyl N-methylanthranilates (IMA), identified in the essential oil of Choisya ternata Kunth (Rutaceae), have been proven to possess polypharmacological properties (antinociceptive, anti-inflammatory, gastro-, hepato-, nephroprotective activities, anxiolytic and antidepressant properties, and likewise an effect on diazepam-induced sleep). In the continuation of our investigation of their urinary-metabolite profiles, we performed GC-MS analyses of the diethyl-ether extracts of selected tissues (liver, kidneys, heart, brain, lungs, quadriceps femoris muscle, and spleen) of rats intraperitoneally treated with MMA or IMA (2 g kg−1). Organ-metabolite profiles of MMA and IMA were qualitatively mutually analogous (varying only in the alcohol moiety of the metabolites), and generally analogous to their urinary-metabolite profiles. The greatest diversity and the highest overall amount of anthranilate metabolites was found in the hepatic tissue. The principal anthranilate-related compounds in the organs of rats treated with MMA, among 12 detected, were the products of ester hydrolysis, N-methylanthranilic and anthranilic acids. In the tissues of IMA-treated rats, among 16 compounds, the most abundant ones were the unmetabolized IMA and N-methylanthranilic acid. A collection of the compositional data regarding the anthranilate-related metabolites was statistically treated by multivariate statistical analysis that provided a better insight into the possible biotransformation pathways.

Synthesis, crystal structure and spectroscopic properties of a new type of pentanuclear zinc(II) complex

The article describes synthesis, crystal structure, ESI-MS and steady state and time-resolved fluorescence spectrum of a pentanuclear zinc(II) compound of composition [ZnII5(HL)2(μ3-OH)2(NO3)4] (1), where H3L is the [1 + 2] condensation product of 4-ethyl-2,6-diformylphenol and 2-amino-2-methyl-1-propanol. The phenol moiety and one of the two alcohol moieties of a H3L get deprotonated and therefore two ONO compartments of [HL]2− in 1 are inequivalent (O(alkoxide)N(imine)O(phenoxide) and O(alcohol)N(imine)O(phenoxide)). Each of the two compartments of each [HL]2− in 1 is occupied by a ZnII ion, to form a ZnII2 fragment. Two such fragments are linked by two μ3-hydroxide ligands to form a dimer-of-dinuclear type ZnII4 fragment. Each of the two alkoxide oxygen atoms bridges one ZnII in the ZnII4 fragment and a fifth ZnII ion (dangling metal ion) to form the pentanuclear system. The structure reveals that it is a new type of pentanuclear system among the related compounds. Notably, the pentanuclear moiety is retained in solution as evidenced from conductance measurement. The title compound exhibits fluorescence behaviour with the emission band at 447 nm on excitation at 384 nm. The quantum yield is 0.05. TCSPC reveals a monoexponential decay in 1. ESI-MS of 1 reveal the appearance of signals of positive ions corresponding to ZnII5, ZnII2 and ZnII metallic systems as well as to H3L ligand system.

Sesquiterpene and monoterpene derivatives from the soil-derived fungus Trichoderma reesei PSU-SPSF013

Three new sesquiterpenes (1-3) and one new monoterpene (4) were isolated from the soil-derived fungus Trichoderma reesei PSU-SPSF013 along with five known compounds including hydroheptelidic acid (5), 5-hydroxy-3-hydroxymethyl-2-methyl-7-methoxychromone (6), adenosine (7), uridine (8) and tyrosol (9). Their structures were elucidated by spectroscopic analyses. The absolute configuration of the secondary alcohol moiety in 2 was assigned using Mosher’s method whereas that of 1, 3 and 4 was established by comparison of their specific rotations with those of structurally related compounds. Compounds 3-5 displayed interesting antifungal activity against Cryptococcus neoformans ATCC90113 with the respective MIC values of 8, 8 and 4 μg/mL. Moreover, only 3 was active against C. neoformans ATCC90112 with the MIC value of 32 μg/mL. Interestingly, 4 and 5 were noncytotoxic towards noncancerous Vero cells.

Colorimetric detection of normetanephrine, a pheochromocytoma biomarker, using bifunctionalised gold nanoparticles

A simple and effective colorimetric method for the detection of normetanephrine (NMN), an O-methylated metabolite of norepinephrine, using functionalised gold nanoparticles is described. This metabolite is an important biomarker in the diagnosis of adrenal tumours such as pheocromocytoma or paraganglioma. The colorimetric probe consists of spherical gold nanoparticles (AuNPs) functionalised with two different ligands, which specifically recognize different functional groups in normetanephrine. Thus, a benzaldehyde-terminated ligand was used for the recognition of the amino alcohol moiety in NMN, by forming the corresponding oxazolidine. On the other hand, N-acetyl-cysteine was chosen for the recognition of the phenolic hydroxyl group through the formation of hydrogen bonds. The selective double molecular recognition between the probe and the hydroxyl and the amino-alcohol moieties of normetanephrine led to interparticle-crosslinking aggregation resulting in a change in the color of the solution, from red to blue, which could be observed by naked eye. The probe was highly selective towards normetanephrine and no color changes were observed in the presence of other neurotransmitter metabolites such as homovanillic acid (HVA) (dopamine metabolite), 5-hydroxyindoleacetic acid (5-HIAA) (serotonin metabolite), or other biomolecules present in urine such as glucose (Glc), uric acid (U.A), and urea. Finally, the probe was evaluated in synthetic urine with constituents that mimic human urine, where a limit of detection of 0.5 μM was achieved.

UV light promoted 'Metal'/'Additive'-free oxidation of alcohols: investigating the role of alcohols as electron donors.

UV light promoted selective oxidation of primary and secondary alcohols has been demonstrated under ‘metal-free’ and ‘additive-free’ conditions. Under the optimized conditions, a variety of aromatic, heteroaromatic, and alicyclic alcohols have been examined for their transformations to the corresponding carbonyl compounds. The mechanistic studies emphasize the important role of substrate (alcohol) and solvent (DMSO) in the generation of superoxide radical which is a vital intermediate for the transformation. This study also highlights the role of air as the oxidant in the oxidation process. Further, the practical application of the strategy has also been demonstrated for the oxidation of the alcoholic moiety in cholesterol.

Synthesis and Fungicidal Activity of Novel Pyrazole-4-carbox-amide Compounds Containing Tertiary Alcohol Moiety

Synthesis and Fungicidal Activity of Novel Pyrazole-4-carbox-amide Compounds Containing Tertiary Alcohol Moiety