Acetyl Derivatives Research Articles

Radical-promoted room-temperature terminal alkyne activation on Au(111)

Exploring on-surface reactions of terminal alkyne derivatives are of primary importance for controlled synthesis of graphyne and graphdiyne-type materials. In this study, room-temperature (RT) adsorption of ethynyl-phenanthrene (EP) and ethynyl-iodophenanthrene (EIP) precursors on Au(111) were investigated by combined scanning tunneling microscopy and density functional theory (DFT) modeling. In contrast to inert adsorption of EP on Au(111), RT deposited EIP molecules are partially deiodinated, which gives rise to various kinds of reaction products. Surprisingly, polymeric chains with length up to ∼ 15 nm were identified. Our DFT modeling evidences that the alkyne activation and covalent coupling on Au(111) are more favored for the deiodinated precursors.

Enantioselective Cyclopropanation Catalyzed by Gold(I)-Carbene Complexes.

The formation of polysubstituted cyclopropane derivatives in the gold(I)-catalyzed reaction of olefins and propargylic esters is a potentially useful transformation to generate diversity, therefore any method in which its stereoselectivity could be controlled is of significant interest. We prepared and tested a series of chiral gold(I)-carbene complexes as a catalyst in this transformation. With a systematic optimization of the reaction conditions, we were able to achieve high enantioselectivity in the test reaction while the cis:trans selectivity of the transformation was independent of the catalyst. Using the optimized conditions, we reacted a series of various olefins and acetylene derivatives to find that, although the reactions proceeded smoothly and the products were usually isolated in good yield and with good to exclusive cis selectivity, the observed enantioselectivity varied greatly and was sometimes moderate at best. We were unable to establish any structure-property relationship, which suggests that for any given reagent combination, one has to identify individually the best catalyst.

Paradoxes and paradigms: the stabilization/resonance energy of some –C(O)– species: acetyl derivatives, metal carbonyls, and amides alike

Paradoxes and paradigms: the stabilization/resonance energy of some –C(O)– species: acetyl derivatives, metal carbonyls, and amides alike

Dimerization of aryl alkynes by Grubbs-Hoveyda complex: investigation of factors affecting the efficiency of the process based on experimental and theoretical approaches

The 2nd generation Grubbs-Hoveyda complex in the presence of slight excess of triphenylphosphine was found as an efficient catalyst for the synthesis of 1,4-disubstituted enynes with preference for head-to-head coupling and Z-selectivity form in the dimerization of various terminal aryl alkynes. Selective product formation was affected by the steric and the electronic properties of the phosphine used as well as the substituents of the alkynes. In order to shed some light on the properties of the alkynes that may affect the yield of desired products a set of 14 alkyne derivatives was characterized on the basis of Density Functional Theory (DFT) using ωB97XD functional and 6-311++G(d,p) basis set. The Atoms in Molecules (AIM) theory was employed for electronic structure and topological analyses of the investigated compounds. The quantitative description of the substituent effect was carried out with assistance of the Harmonic Oscillator Model of Aromaticity (HOMA), charge of the Substituent Active Region (cSAR(X)) and Substituent Effect Stabilization Energy (SESE). It was found that substituents in the phenyl ring are able to affect the geometric and electronic structure of the alkynyl moiety. The experimental and theoretical results revealed that high activity of the investigated ruthenium complex towards dimerization of alkynes is related with σ-donor ability and bulkiness of added phosphine combined with small size aryl alkyne bearing electron-withdrawing group. However, the influence of the structure of aryl alkyne on the catalyst activity could not be easily explained only on the basis of steric and electronic factors.

A Facile Stereoselective Bis‐Trifluoromethylselenolation Reaction of Alkynes with AgSeCF3 and N‐Bromosuccinimide

AbstractA facile stereoselective bis‐trifluoromethylselenolation reaction of alkyne derivatives was realized for the first time. The reaction of alkyne derivatives and AgSeCF3 was found to proceed in the presence of N‐bromosuccinimide and water in tetrahydrofuran and afforded bis‐trifluoromethylselenolated products in moderate‐to‐excellent yields. The new methodology enables one‐pot synthesis with a broad substrate range.

Laminarin acetyl esters: Synthesis, conformational analysis and anti-viral effects

Chemical modification of polysaccharides is important for expanding their applications and gaining new insights into their structure-property relationships. Here we reported the synthesis, characterization, and anti-viral activities of laminarin acetyl derivatives. The chemical structure and chain conformation of acetylated laminarin were characterized by FT-IR, H1 NMR, AFM, UV–vis spectrum, and induced circular dichroism based on a modified Congo Red assay (ICD-CR assay). The inhibition effect of laminarin and its acetyl derivatives on HSV-1 was evaluated by viral plaque assay and virus-associated DNA/protein change. Acetylation modification was found to trigger the conformation transition of laminarin from triple helix to single helix, and the extent of transition can be tuned by the degree of substitution. The single helical acetylated laminarins were found to be stable in neutral aqueous solution and exhibited no cytotoxicity. However, the acetylated laminarin exhibited declined antiviral activity after modification.

4-(4-(((1H-Benzo[d][1,2,3]triazol-1-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)-7-chloroquinoline

The 1,2,3-triazole ring system can be easily obtained by widely used copper-catalyzed click reaction of azides with alkynes. 1,2,3-triazole exhibits myriad of biological activities, including antibacterial antimalarial, and antiviral activities. We herein reported the synthesis of quinoline-based [1,2,3]-triazole hybrid derivative via Cu(I)-catalyzed click reaction of 4-azido-7-chloroquinoline with alkyne derivative of hydroxybenzotriazole (HOBt). The compound was fully characterized by proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), correlated spectroscopy (1H-1H-COSY), heteronuclear single quantum coherence (HSQC) and distortionless enhancement by polarization transfer (DEPT-135 and DEPT-90) NMR, ultraviolet (UV) and Fourier-transform infrared (FTIR) spectroscopies, and high-resolution mass spectrometry (HRMS). Computational studies were enrolled to predict the interaction of the synthesized compound with acetylcholinesterase, a target of primary relevance for developing new therapeutic options to counteract neurodegeneration. Moreover, the drug-likeness of the compound was also investigated by predicting its pharmacokinetic properties.

Heterocyclic azides: advances in their chemistry

This is the first systematic review on the synthesis and reactions of heterocyclic azides with acetylene and acetonitrile derivatives, alkenes, enamines and dicarbonyl compounds. Examples are given for the application of these reactions to the synthesis of mono-, bi- and tricyclic compounds and ensembles of various heterocycles, <i>e.g</i>., azines and azoles (including 1,2,3-triazole derivatives and nonaromatic 1,2,3-triazolines), amidines and diazo compounds. Methods for the synthesis of supramolecular structures, coordination compounds, ligands, bioconjugates and biologically active compounds based on reactions with heterocyclic azides are considered. The review describes the use of these transformations in biological chemistry to study processes in living systems, as well as in materials chemistry for the production of luminophores and sensors for metals. Original studies published mainly over the past 15 years are discussed.<br> The bibliography includes 222 references.

Synthesis and biological activity of acetylene compounds derivatives of benzoin

Paper involves and some acetylene compounds from benzoin 4,4-dimethyl benzoin, 4-methyl benzoin, 4,4-dichloro benzoin, 4,4-dibromo benzoin and 4-dimethyl amino benzoin treated with 3-bromo propyne yielded series of new acetylene compounds were characterized by FTIR, 1HNMR and C-H-N. The compounds good activity of antibacterial.

Controlled Alternating Metathesis Copolymerization of Terminal Alkynes.

Terminal alkynes display high reactivity toward Ru-carbene metathesis catalysts. However, the formation of a less reactive bulky carbene hinders their homopolymerization. Simultaneously, the higher reactivity of alkynes does not allow efficient cross propagation with sterically less-hindered cycloalkene monomers, resulting in inefficient copolymerization. Nonetheless, terminal alkynes undergo rapid cross-metathesis with vinyl ethers. Therefore, an efficient cross propagation can be achieved with terminal alkynes and cyclic enol ether monomers. Here, we show that terminal alkyne derivatives can be copolymerized in an alternating fashion with 2,3-dihydrofuran using Grubbs' third generation catalyst (G3). A linear relationship of the number-average molecular weight versus monomer to initiator ratio and block copolymer synthesis confirmed a controlled copolymerization. The SEC and NMR analyses of the synthesized copolymers confirmed the excellent control over molecular weight and exclusive alternating nature of the copolymer. The regioselective chain transfer of G3 to vinyl ether and the high reactivity of the Fischer-type Ru carbene toward terminal alkynes was also exploited for polymer conjugation. Finally, the presence of an acid labile backbone functionality in the synthesized alternating copolymers allowed complete degradation of the copolymer within a short time interval which was confirmed by SEC analyses.

SESQUITERPENE LACTONS FROM AERIAL PARTS OF ARTEMISIA CAMPESTRIS (var. MARSCHALLIANA) SPRENG.

About 500 species of wormwood are known in the world. In the flora of Azerbaijan, this genus is represented by 42 taxa. The main chemicals in wormwood are shown to be sesquiterpene lactones, coumarins, steroids, and essential oils. From the aerial parts of Artemisia campestris (var. Marschalliana) Spreng., collected during the phenological phase of budding, an acetone extract was obtained, which, after removal of the solvent, was subjected to the column chromatography in neutral alumina oxide (II degree of activity) and eluted graduality with hexane, benzene, chloroform and their mixtures of increasing polarity. As a result of chromatographic separation, two sesquiterpene lactones of the eudesmann type were isolated - α-santonin (substance I) with m.p. 170–172 °С and artemisin (substance II) m.p. 201–203 °С. Moreover, an acetyl derivative of artemisin (substance III) with m.p. 196–198°C, the identification of which was carried out on the basis of physicochemical and spectral data (UV, IR, and 1H, 13C, 13C Dept 45, 13C Dept 90, 13C Dept 135 NMR spectra was obtained. Substances I and II are isolated from Artemisia campestris (var. Marschalliana) Spreng. for the first time.

Site Isolation in Metal–Organic Layers Enhances Photoredox Gold Catalysis

Herein, we report the synthesis of a metal-organic layer, Hf-Ru-Au, containing Ru(bipyridine)32+-type photosensitizers and (phosphine)-AuCl catalysts for photoredox Au-catalyzed cross-coupling of allenoates, alkenes, or alkynes with aryldiazonium salts to afford furanone, tetrahydrofuran, or aryl alkyne derivatives, respectively. Site isolation of (phosphine)-AuCl complexes in Hf-Ru-Au prevents Au catalyst deactivation via ligand redistribution, Au(I) disproportionation, and aryl-phosphine reductive elimination, while the proximity between the Ru photosensitizers and Au catalysts enhances catalytic efficiency, with 14-200 times higher activity over those of the homogeneous controls in the cross-coupling reactions.

Structure of Two Acetylene Derivatives of Salicylic Acid

Structure of Two Acetylene Derivatives of Salicylic Acid

Water activity influence on the simultaneous production of DON, 3-ADON and 15-ADON by a strain of Fusarium graminearum ss of 15-ADON genotype

The influence of aw on DON and its acetyl derivatives biosynthesis by a strain of Fusarium graminearum s.s. (ITEM 4606) which produces DON, 3-ADON and 15-ADON was evaluated. Trichothecene production was studied on agar wheat 2% at 0.95 and 0.99 aw at different temperatures (10, 15, 20, 25 and 30 °C) and incubation times (7, 14, 21 and 28 days). Statistical analysis (ANOVA) showed that aw, temperature, incubation time and their interactions were significant on the production of DON, 3-ADON and 15-ADON (p < 0.0001). The pattern of toxin production was influenced by aw, showing differences for the three toxins. The maximum accumulation of DON occurred at 30 °C at 0.99 aw (14 d) and at 25 °C at 0.95 aw (7 and 21 d). The highest concentration of 3-ADON at 0.95 aw was observed at 25 °C and 7 days, and it was significantly higher than all the other values registered. At 0.99 aw, the maximum occurred at 30 °C and 21 days, but another significantly high accumulation was observed at 28 days at the same temperature. For 15-ADON, at 0.95 aw, the highest amount of toxin was accumulated at 10 °C, both at 7 and 28 days. At 0.99 aw, a maximum was observed at 10 °C and 7 days, significantly different from the values observed at the other conditions.The toxin accumulated at a higher concentration at 0.95 aw was 15-ADON (173.2 μg/g) and at 0.99 aw, 3-ADON (370.6 μg/g). A marked influence of aw on the maximum toxin accumulation with respect to temperature and time was observed for trichothecene production. This is an important fact to consider when designing predictive models to prevent toxin contamination, both in the field and during storage, especially in intermediate drying stages.

Acetyl-L-carnitine improves erectile function in bilateral cavernous nerve injury rats via promoting cavernous nerve regeneration

ABSTRACT Introduction Acetyl-L-carnitine (ALCAR), an acetyl derivative of L-carnitine, has been proven to promote nerve repair and regeneration in a variety of neurodegenerative diseases. Neurogenic erectile dysfunction (NED) caused by CN injury is a common complication after radical prostatectomy, which lacks efficient curative treatments. Objective Although attempts have been made to apply ALCAR to treatment of peripheral neuropathy, the effects of ALCAR on NED remain unknown. Therefore, we intend to explore the potential role of ALCAR in the treatment of NED. Methods A rat model of bilateral cavernous nerve injury (BCNI) was established by crushing the CN 5 millimeters distal to the major pelvic ganglion (MPG). Twenty-four BCNI rats were randomly divided into BCNI group, BCNI+ALCAR-LD (50 mg/kg/day) group, and BCNI+ALCAR-HD (100 mg/kg/day) group, whereas the remaining eight age-matched rats were sham-operated as controls. Fourteen days after intraperitoneal injection of ALCAR, erectile function was evaluated by measuring intracavernosal pressure and mean arterial pressure. The penile tissues and CNs at the distal damage point were collected from each group of rats for subsequent histological and molecular biological analysis. Rat Schwann cell line S16 was used for CCK-8 and wound healing assay, and the expressions of SC markers Pmp22 and nerve growth factor (NGF) were verified by PCR. Results First, we found that the erectile function of rats in the BCNI model group was severely impaired, which was improved considerably in both BCNI+ALCAR-LD and BCNI+ALCAR-HD groups. Then, we observed that the penis was fibrotic after denervation in the BCNI group, which was manifested as decreased smooth muscle content and increased collagen content in the corpus cavernosum, and high expression of fibrosis indicators including TGF-beta, CTGF, and Smad 2/3. The above changes were alleviated after the administration of low and high-dose ALCAR. Meanwhile, our results also showed that after ALCAR treatment, the NO/cGMP pathway was promoted and the RhoA/ROCK pathway was inhibited in the corpus cavernosum of BCNI rats. Further, rats treated with ALCAR had high expression of ATF3 and S100 in the distal nerve tissues of the CN extrusion site, indicating the repairing effect of ALCAR on the CN. In vitro experiments showed that ALCAR promoted the proliferation and migration of SC, and increased the expression of Pmp22 and NGF. Conclusions ALCAR could boost CN repair and regeneration, thereby suppressing penile fibrosis and improving penile erection. ALCAR could inhibit penile fibrosis and improve penile erection by promoting proliferation and migration of SC and secretion of NGF to promote nerve repair and regeneration. Our study provides new insight into the therapeutic effect of ALCAR and preclinical evidence for a potential treatment strategy for NED. Disclosure Work supported by industry: no.

Novel octanuclear copper(I) clusters [Cu8{(N)-(μ4-S)}4(μ3-I)2I2(PPh3)2] produced via reductive S-S bond cleavage of disulfide Schiff base ligands and their use as efficient heterogeneous catalysts in CuAAC click reaction

Thiol/disulfide interconversion, catalyzed by metal ions and enzymes, is a fundamental transformation and plays important roles in biological systems. The thiolates, produced in these reactions, are particularly versatile sulfur-containing ligands that can bind to metals or group of metals via a variety of modes and this versatility can lead to the formation of polymeric chains and metal clusters with high nuclearity. Herein, we report the facile one pot synthesis of novel octanuclear copper(I) complexes, [Cu8{(N)-(μ4-S)}4(μ3-I)2I2(PPh3)2] (1–5), by the reaction of copper(I) iodide and disulfide Schiff base molecules (R-CHN˗Ph˗S˗S˗Ph-NCH-R, RMePh = 4-MePh (SB1), RMeOPh = 4-MeOPh (SB2), RMeSPh = 4-MeSPh (SB3), RBrPh = 4-BrPh (SB4), and RFur = 2-furan (SB5)) in the presence of PPh3 in dichloromethane-acetonitrile or chloroform-acetonitrile solution under ambient conditions. Single-crystal X-ray structure analyses of these clusters confirm the presence of Cu8S4I4 core stabilized by the chelating Schiff base thiolate fragment R-CHN˗Ph˗Sˉ produced by the reductive cleavage of disulfide bond, Iˉ, and PPh3. DFT calculations have been performed to describe a speculative mechanism of cluster formation. The octanuclear clusters [Cu8{(N)-(μ4-S)}4(μ3-I)2I2(PPh3)2] (1–5) have been exploited as efficient heterogeneous catalysts for the green synthesis of 1,2,3-triazoles from NaN3, alkyl halides, and alkyne derivatives (CuAAC reaction) under mild conditions.

Cyclization of N-acetyl derivative: Novel synthesis – azoles and azines, antimicrobial activities, and computational studies

Abstract 2-Pyridone is considered as one of the most famous efficient pharmaceutical compounds. Many approaches were discovered to synthesize 2-pyridone. In this present research, chloroacetylation of benzylamine at simple conditions, EtONa/EtCOONa produced N-benzyl-2-chloroacetamide 2. Compound 2 was allowed to react with different reagents. These reagents are acetylacetone, ethyl cyanoacetate, ethyl acetoacetate, and diethyl malonate, creating 2-pyridone derivatives with a good yield. The structures of the prepared compounds were elucidated by spectral data (IR, 1HNMR, and 13CNMR). The synthesized compound was tested for its antimicrobial activity against the Gram-positive (Staphylococcus aureus) and the Gram-negative (Escherichia coli) bacteria. In addition, the antifungal activities of the compounds were tested against two fungi (Candida albicans and Aspergillus flavus). Molecular docking studies were applied using the Autodock vina method. Theoretical methods prove all the experimental results by using molecular docking using Autodock vina and by ADEMT studies. The docking results represent that compound 20 had the best docking free energy, and it is the effective compound toward the selected bacterial and fungal proteins. ADME studies showed that the only compound 18 could cross the blood–brain barrier, and compound 15 was predicted to be soluble.

Estimation of Electron Distribution over Dinuclear Organometallic Molecular Wires by "IR Tag" Analysis of Ancillary Acyl-Cp Ligands.

Understanding the details of electronic properties of mixed-valence (MV) states of organometallic molecular wires is essential to gain insights into electron transfer phenomena. Although the field of MV chemistry is matured, there remain issues to be solved, which cannot be accessed by the conventional analytical methods. Here, we describe the synthesis and properties of diruthenium bridging (diethynylbenzene)diyl wires, (μ-p and m-C≡C-C6H4-C≡C){RuCpR(dppe)}2 1, with the acyl-substituted cyclopentadienyl rings [CpR: Cpe; η5-C5H4COOMe (a-series: ester derivatives), Cpa; η5-C5H4COMe (b-series: acetyl derivatives)], which are installed as IR-tags to estimate electron densities at the metal centers in the MV species. The electrochemical and IR/near IR-spectroelectrochemical studies reveal that the two metal centers in the para-isomers p-1a,b + interact with each other more strongly than those in the meta-isomers m-1a,b + . Electron-spin resonance study also supports the radicals being delocalized over the Ru-(p-C≡C-C6H4-C≡C)-Ru moieties in p-1a,b + . The spectroelectrochemical IR study shows significant higher-energy shifts of the ν(C=O) vibrations brought about upon 1e-oxidation. Spectral simulation on the basis of the Bloch equations allows us to determine the electron transfer rate constants (k et) between the two metal centers being in the orders of 1012 s-1 ( p-1 + ) and 109 s-1 ( m-1 + ). The shifts of the ν(C=O) bands reveal that the charge densities on the para-isomers p-1a,b + are widely delocalized over the Ru-(p-C≡C-C6H4-C≡C)-Ru linkages in contrast to the meta-isomers m-1a,b + , where the electron densities are mainly localized on the metal fragments, as supported by the density functional theory and time-dependent density functional theory studies as well as comparison with the reference mononuclear acetylide complexes, C6H5-C≡C-RuCpR(dppe) 2. We have successfully demonstrated that the carbonyl groups (>C=O) in the ancillary Cp ligands also work as IR-tags to report detailed information on the electron densities at the metal centers and the electron distribution over MV complexes as well.

Structural Characterization of Mono- and Dimethylphosphatidylethanolamines from Various Organisms Using a Complex Analytical Strategy including Chiral Chromatography

Two minor phospholipids, i.e., mono- and/or dimethylphosphatidylethanolamines, are widespread in many organisms, from bacteria to higher plants and animals. A molecular mixture of methyl-PE and dimethyl-PE was obtained from total lipids by liquid chromatography and further identified by mass spectrometry. Total methyl-PE and dimethyl-PE were cleaved by phospholipase C, and the resulting diacylglycerols, in the form of acetyl derivatives, were separated into alkyl-acyl, alkenyl-acyl, and diacylglycerols. Reversed-phase LC/MS allowed dozens of molecular species to be identified and further analyzed. This was performed on a chiral column, and identification by tandem positive ESI revealed that diacyl derivatives from all four bacteria were mixtures of both R and S enantiomers. The same applied to alkenyl-acyl derivatives of anaerobic bacteria. Analysis thus confirmed that some bacteria biosynthesize phospholipids having both sn-glycerol-3-phosphate and sn-glycerol-1-phosphate as precursors. These findings were further supported by data already published in GenBank. The use of chiral chromatography made it possible to prove that both enantiomers of glycerol phosphate of some molecular species of mono- and dimethylphosphatidylethanolamines are present. The result of the analysis can be interpreted that the cultured bacteria do not have homochiral membranes but, on the contrary, have an asymmetric, i.e., heterochiral membranes.

OBTAINING SUPRAMOLECULAR COMPLEXES OF ANGIDROLAGOQUILINE WITH GLYCYRRHISINOIC ACID AND ITS SALTS AND STUDYING THEIR SPECIFIC HEMOSTATIC ACTIVITY

The hemostatic effect of drugs of the genus Lagochilus (Lamiaceae) is due to the content in its composition of four atomic alcohol diterpenoid lagochiline, alkaloid stahydrine, vitamin K and tannins. On the basis of lagochilin, a number of acetyl and isopropylidene derivatives were obtained. It has been shown that the hemostatic activity in a certain way depends on the number of free hydroxyl groups of lagochilin and its derivatives. However, lagochiline derivatives are poorly soluble in water, which limits their bioavailability. Chemical modification of lagochilin is carried out mainly by hydroxyl groups with the production of esters or succinates with dibasic anhydrides.&#x0D; For the first time, water-soluble supramolecular complexes based on the diterpenoid lactone an-hydrolagoquiline with the triterpene saponin glycyrrhizic acid (GA) and its monoammonium (MASGA) and monopotassium salts (MPSGA) in various molar ratios were obtained. The physicochemical and spectral characteristics of the resulting complex compounds have been studied. Screening studies were carried out to study the specific hemostatic activity of the obtained supramolecular complexes. Among Lagochilin Lagochirzine and their derivatives at a dose of 10 mg/kg, Lagochilin had the most active effect on bleeding time, followed by Anhydrolagochilin–Lagohirzin. The greatest effect on bleeding time at a dose of 10 mg/kg among supramolecular complexes with HA was shown by HA-AHL, which in a ratio of 2 : 1 it was impossible to determine the bleeding time, and in a ratio of 4 : 1 it reduced the bleeding time by 12 times, and the amount of blood loss by 42 times.