Acetylenic Acids Research Articles

Study on gas sensitivity of ZnO@NiO loaded functional carbon materials

We carefully design and prepare a kind of functional carbon material AHC (acetylenic acid - hexamethylene diamine - carbon) using alkynyl acid and cyclohexadiene as raw materials, which load on ZnO@NiO to prepare acetone gas sensor. Studies show that the most appropriate amount of AHC on ZnO@NiO is 0.12% and the best working temperature is 200°C. By comparison, ZnO@NiO@AHC sensor for 100 ppm acetone gas has a maximum response value of 49.08, which is twice as high as of ZnO@NiO sensor. The minimum detection limit is 1 ppm. There is an approximate linear relationship between the concentration and the sensitivity in the range of 1–300 ppm.

Caffeoylquinic acids protect against alcoholic liver injury and rare C10 acetylenic acids from Erigeron breviscapus

Three new compounds (1–2, 4) along with ten known ones (3, 5–13), were isolated from the whole plant of Erigeron breviscapus. Compounds 1 and 2, two novel C10 acetylenic acids and compound 4, a jasmone glucoside were elucidated by the detailed analysis of 1D and 2D NMR, HRESIMS spectra, and experimental and calculated electronic circular dichroism (ECD). Compounds 1–3 represent the first example of acetylenic acids incorporating C10 skeleton from E. breviscapus. In addition, the antioxidant effects of all compounds were evaluated by ferric reducing power, 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate acid) (ABTS) and 2.2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. Our results indicated the significant antioxidant activity of caffeoylquinic acids. Additionally, compounds 10–11 and 13 played protective role on alcoholic liver injury cells in a dose-dependent manner.

Metal-Catalyzed Cascade Reactions between Alkynoic Acids and Dinucleophiles: A Review

Cascade reactions provide a straightforward access to many valuable compounds and reduce considerably the number of steps of a synthetic sequence. Among the domino and multicomponent processes that involve alkynes, the cascade reaction between alkynoic acids and C-, N-, O- and S-aminonucleophiles stands out as a particularly powerful tool for the one-pot construction of libraries of nitrogen-containing heterocyclic compounds with scaffold diversity and molecular complexity. This reaction, based on an initial metal-catalyzed cycloisomerization that generates an alkylidene lactone intermediate, was originally catalyzed by gold(I) catalysts, along with silver salts or Brönsted acid additives, but other alternative metal catalysts have emerged in the last decade as well as different reaction media. This review examines the existing literature on the topic of metal-catalyzed cascade reactions of acetylenic acids and dinucleophiles and discusses aspects concerning substrate/catalyst ratio for every catalyst system, nature of the aminonucleophile involved and substrate scope. In addition, alternative solvents are also considered, and an insight into the pathway of the reaction and possible intermediates is also provided.

Correction to “Investigation of the Deactivation and Reactivation Mechanism of a Heterogeneous Palladium(II) Catalyst in the Cycloisomerization of Acetylenic Acids by In Situ XAS”

Correction to “Investigation of the Deactivation and Reactivation Mechanism of a Heterogeneous Palladium(II) Catalyst in the Cycloisomerization of Acetylenic Acids by <i>In Situ</i> XAS”

Chemical Diversity and Bioactivity of Marine Sponges of the Genus Oceanapia: A Review

: The marine sponges of the genus Oceanapia sp. is comprised of more than 50 species and are distributed in the seas around the tropical and subtropical regions. They are mainly found in the northern Indian oceans, Japan, and the south pacific coast. They are highly colored and known to be a rich source of various secondary metabolites, particularly, alkaloids. Several other secondary metabolites were also reported from this genus which include terpenes, sphingolipids, ceramides, cerebrosides, acetylenic acids, and thiocyanatins, etc. Many of these compounds isolated from this genus exhibited various biological properties including anticancer, antimicrobial, anti-HIV, ichthyotoxicity and nematocidal activities. Although several secondary metabolites have been reported from this genus, a dedicated review of the chemicals and biological activities of this genus is so far lacking. Keeping this in mind this review describes the various chemical entities isolated from the sponges of the genus Oceanapia detailing their chemical structures along with their reported biological properties.

Palladium-Catalyzed Domino Cycloisomerization/Double Condensation of Acetylenic Acids with Dinucleophiles

Metal-catalyzed cascade processes based on hydrofunctionalization of alkynes are receiving much more attention because of their potential to provide advantageous approaches to otherwise synthetically challenging compounds. An alternative catalyst system has been found for the domino cycloisomerization/cyclocondensation reaction involving acetylenic acids and heterodinucleophiles. A CNN pincer palladium(II) complex, acting as a homogeneous catalyst, provides the corresponding polyheterocycles with a higher substrate/catalyst ratio. Other palladium sources were also tested and discarded, and a number of mechanistic studies including poisoning assays, kinetic plots, TEM images, XRD spectra and UPLC-MS analysis of reaction intermediates were conducted in order to shed light on the role of this pincer catalyst and the catalytic cycle involved in the cascade reaction. As a result, a more nuanced mechanism is tentatively proposed.

Photoinduced radical cascade cyclization of acetylenic acid esters with oxime esters to access cyanalkylated coumarins.

A photoinduced radical cascade cyclization of acetylenic acid esters with oxime esters is described, providing cyanalkylated coumarins in superior yields under mild conditions. Radical capture and luminescence quenching experiments showed that this transformation was accomplished via a radical addition/5-exo spirocyclization/1,2-ester migration process.

Synthesis of biologically active heterocyclic compounds from allenic and acetylenic nitriles and related compounds

Abstract Cyclic and polycyclic compounds containing moieties such as imidazole, pyrazole, isoxazole, thiazoline, oxazine, indole, benzothiazole and benzoxazole benzimidazole are prized molecules because of the various pharmaceutical properties that they display. This led Prof. Landor and co-workers to engage in the synthesis of several of them such as alkylimidazolenes, oxazolines, thiazolines, pyrimidopyrimidines, pyridylpyrazoles, benzoxazines, quinolines, pyrimidobenzimidazoles and pyrimidobenzothiazolones. This review covers the synthesis of biologically active heterocyclic compounds by the Michael addition and the double Michael addition of various amines and diamines on allenic nitriles, acetylenic nitriles, hydroxyacetylenic nitriles, acetylenic acids and acetylenic aldehydes. The heterocycles were obtained in one step reaction and in most cases, did not give side products. A brief discussion on the biological activities of some heterocycles is also provided.

Investigation of the Deactivation and Reactivation Mechanism of a Heterogeneous Palladium(II) Catalyst in the Cycloisomerization of Acetylenic Acids by In Situ XAS .

A well-studied heterogeneous palladium(II) catalyst used for the cycloisomerization of acetylenic acids is known to be susceptible to deactivation through reduction. To gain a deeper understanding of this deactivation process and to enable the design of a reactivation strategy, in situ X-ray absorption spectroscopy (XAS) was used. With this technique, changes in the palladium oxidation state and coordination environment could be studied in close detail, which provided experimental evidence that the deactivation was primarily caused by triethylamine-promoted reduction of palladium(II) to metallic palladium nanoparticles. Furthermore, it was observed that the choice of the acetylenic acid substrate influenced the distribution between palladium(II) and palladium(0) species in the heterogeneous catalyst after the reaction. From the mechanistic insight gained through XAS, an improved catalytic protocol was developed that did not suffer from deactivation and allowed for more efficient recycling of the catalyst.

An iodine-mediated new avenue to sulfonylation employing N-hydroxy aryl sulfonamide as a sulfonylating agent.

A novel and highly efficient I2/K2CO3 mediated regioselective sulfonylation of thiophenols, aryl acetylenic acid and aromatic alkynes with N-hydroxy sulfonamide has been developed. N-hydroxy sulfonamide has been used for the first time for the synthesis of these sulfones. The scope and versatility of the reaction has been demonstrated by the regio- and stereoselective synthesis of different analogs of sulfones with various structural features.

A Construction of α-Alkenyl Lactones via Reduction Radical Cascade Reaction of Allyl Alcohols and Acetylenic Acids.

An iron-catalyzed cascade reaction of radical reduction of allyl alcohols and acetylenic acids to construct polysubstituted α-alkenyl lactones has been developed. In this paper, various allyl alcohols can form allyl ester intermediates and are further transformed into alkyl radicals, which form products through intramolecular reflex-Michael addition. In addition, this method can be used to prepare spirocycloalkenyl lactones. Interestingly, this protocol can be used to synthesize the skeleton structure of natural products. Moreover, the product can be further transformed into a β-methylene tetrahydrofuran and tetrahydrofuran diene.

НЕКОТОРЫЕ СПОСОБЫ СИНТЕЗА АЦЕТИЛЕНОВЫХ КИСЛОТ

The article presents some methods for the synthesis of acetylene mono, dicarbonoaliphatic, aromatic, heterocyclic acids. Among them, some possess antifungal and biological properties. By the interaction of acids or acid chlorides with the corresponding alcohols, esters can be obtained. Their biological properties, as well as some chemical transformations, were studied. Many synthetic acetylenic acids and their derivatives were synthesized mainly by the Grignard reaction and other methods in order to study their physiological activity. Some of them have gained application as a stabilizer of corrosion methods and others.

Single-Molecule Observation of the Intermediates in a Catalytic Cycle.

The development of catalysts benefits from knowledge of the intermediate steps that accelerate the transformations of substrates into products. However, key transient species are often hidden in ensemble measurements. Here, we show that a protein nanoreactor can sample the intermediate steps in a catalytic cycle by the continuous single-molecule observation of a stoichiometric reaction in solution. By monitoring changes in the flow of ionic current through an α-hemolysin protein pore, we observed three intermediate metal-ligand complexes in a gold(I)-catalyzed reaction that converts an acetylenic acid to an enol lactone, revealing a transitional coordination complex that had been previously unobserved. A kinetic isotope effect helped assign the various metal-ligand species. Measurements of the lifetimes of the intermediates allowed a full kinetic analysis of the metal-catalyzed reaction cycle.

Synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) by azide–alkyne “click” chemistry

The synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) (isobutylene–isoprene rubber, IIR) with substitution levels ranging from 1 to 4 mol% and different spacer lengths was accomplished through azide–alkyne Huisgen cycloaddition. Azido-functionalized IIR was first prepared by reacting brominated IIR with sodium azide to full conversion in a 90:10 tetrahydrofuran/N,N-dimethylacetamide mixture. The click reaction of azido-functionalized IIR with acetylenic acids, which was carried out using the copper(I) bromide/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst system in tetrahydrofuran, yielded carboxylated IIRs. The products were characterized by 1H NMR and FT-IR spectroscopy, and their molecular weight was determined by size exclusion chromatography analysis. The conversion to carboxylated groups reached up to 100% as determined by NMR spectroscopy but was highly dependent on the type of solvent and the amounts of catalysts and reactants used in the procedures. The synthesis of carboxylated IIR was achieved in high yield starting from brominated substrates, which were first converted to azides and used in the copper-catalyzed azide–alkyne Huisgen cycloaddition reaction with acetylenic acids containing different aliphatic spacer lengths. Optimization of the reaction conditions was critical to avoid the formation of gel particles in the reactions and to achieve full conversion of the bromide to carboxylate derivatives.

Anti-oral common pathogenic bacterial active acetylenic acids from Thesium chinense Turcz.

Discovery of agents for oral infectious diseases is always encouraged in natural products chemistry. A bioassay-guided isolation led to the isolation of two new acetylenic acids (1, 2) along with seven known ones (3-9) from the ethanol extract of Thesium chinense Turcz, a commonly used oral anti-bacterial and anti-inflammatory herb. Their structures were elucidated on the basis of spectroscopic and chemical evidence. Exocarpic acid (3) demonstrated the most promising activity against three tested oral pathogenic bacterial strains, Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans, with minimum inhibitory concentration values of 0.86, 3.43, and 13.70μg/mL, respectively. Compounds 1, 2, 4, 5 and 7 also showed potential activities against periodontal bacteria (P. gingivalis, F. nucleatum).

Synthesis of Acetylenic Amides with Propyllactam Moieties by In Situ DBU or DBN Ring-Opening Rearrangement in the Presence of Acetylenic Esters

DBN (1,5-diazabicyclo[4.3.0]non-5-ene) and DBU (1,8-diaza­bicyclo[5.4.0]undec-7-ene) react with methyl esters of acetylenic acids and excess water (the reactant molar ratio 1:1, in aqueous MeCN, at 20–25 °C, for 48 h) to afford acetylenic amides with pyrrolidone and caprolactam moieties in 89–100% yields. The synthesis involves amines formed in situ from the cyclic amidines, which further react with acetylenic esters.

New 2-Methoxy Acetylenic Acids and Pyrazole Alkaloids from the Marine Sponge Cinachyrella sp.

Three new 2-methoxy acetylenic acids (1–3) and a known derivative (4), in addition to three new natural pyrazole alkaloids (5–7) were isolated from an Indonesian marine sponge of the genus Cinachyrella. Compounds 5 and 6 have previously been reported as synthetic compounds. The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopy as well as by mass spectrometric data. The absolute configuration of the new acetylenic acid derivatives (1–3) was established by ECD spectroscopy. All isolated compounds were evaluated for their cytotoxicity against L5178Y mouse lymphoma cells. Compounds 1–4 exhibited strong activity with an IC50 value of 0.3 µM. A plausible biosynthetic pathway for the pyrazole metabolites 5–7 is proposed.

Boranes in Organic Chemistry 1. α-Carbonylalkyl- and β-Oxyalkylboranes in Organic Synthesis

&lt;p&gt;This review is devoted to the synthesis of a-carbonylalkyl- and β-hydroxy-alkyl boranes and their use in organic synthesis. a-Carbonyl-alkylboranes include several heteroatomic compounds, in particular, [1.2.3]-diazaborinines, uracyl boronic acids, and [1.2.3.4]-diaza-diboretes. The latter type has been obtained by the ketene aminoborations. The reactions of halogenboranes with diazoesters and sulfur ylides resulting in formation of a-carbonyl alkylborates containing diazofunction or ylide structural fragment are described. Amino and halogen boration of acetylenic acid esters was also used for the synthesis of a-carbonyl alkyl boranes. Reactions involving Cr-carbene complexes and acetylenic borone esters were presented for the synthesis of naphthoquinone boronic acids. The formation of amidoboranes by boration of dichloroacetanilides was remined. Boration of 4,8-dimethoxy-2-quinolone with trimethylborates leading to 2-quinolone-3-boronic acid was described. The common synthetic method to a-carbonyl alkyl boranes based on the hydroboration of acrylic acid derivatives was discussed. The results of enhydrazones hydroboration, leading to stable cyclic complexes have been mentioned. The interaction of a-bromoketones with trialkyl or dialkylboranes represents as a general synthetic method to a-carbonyl alkyl boranes. Synthetic approaches to â-hydroxy alkyl boranes are performed. The wide spread hydroboration of vinyl and allyl esters received a well-described attention. The hydroboration of cyclanone enol acetates, 3-keto- and 17-keto-steroids and cyclic allyl alcohol acetates was discussed. The results of aliphatic and alicyclic vinyl esters (including dihydrofuran derivatives) boralylation leading to β-hydroxy alkyl boranes have been envisaged. The synthesis of optically active β-hydroxy alkyl boranes using chiral borane hydrides was discussed. The heterocyclic boran dihydrides are obtained by the hydroboration of dihydropyranes, chromenes and flavenes. Borosilylation of allyl allenylic esters was also been envisaged. The synthetic scheme to optically active boranes and further optically active alcohols were presented. The problems of selectivity regularities in hydroboration reaction by intermolecular complex formations have been discussed.&lt;/p&gt;

New Acetylenic Acids and Derivatives from the Edible Mushroom Craterellus lutescens (Cantharellaceae).

Thirteen new acetylenic acids and their derivatives, craterellynes G-Q (1, 2, 4-10, 12, 13), 9-epi-craterellyne H (3), and 14-O-ethyl-craterellyne O (11), were isolated from the fruiting bodies of edible mushrooms Craterellus lutescens. The structures of these compounds were identified by various spectroscopic and chemical means. The stereoconfigurations of 1-13 were elucidated by the combination of acetonide formation, J-based configuration analysis, and modified Mosher's method. Craterellyne I exhibited cytotoxicities against human cancer strains and inhibition of nitric oxide (NO) production, as well as weak antimicrobial activity against Candida albicans.

Specific Inhibition of Acyl-CoA Oxidase-1 by an Acetylenic Acid Improves Hepatic Lipid and Reactive Oxygen Species (ROS) Metabolism in Rats Fed a High Fat Diet

A chronic high fat diet results in hepatic mitochondrial dysfunction and induction of peroxisomal fatty acid oxidation (FAO); whether specific inhibition of peroxisomal FAO benefits mitochondrial FAO and reactive oxygen species (ROS) metabolism remains unclear. In this study a specific inhibitor for the rate-limiting enzyme involved in peroxisomal FAO, acyl-CoA oxidase-1 (ACOX1) was developed and used for the investigation of peroxisomal FAO inhibition upon mitochondrial FAO and ROS metabolism. Specific inhibition of ACOX1 by 10,12-tricosadiynoic acid increased hepatic mitochondrial FAO via activation of the SIRT1-AMPK (adenosine 5'-monophosphate-activated protein kinase) pathway and proliferator activator receptor α and reduced hydrogen peroxide accumulation in high fat diet-fed rats, which significantly decreased hepatic lipid and ROS contents, reduced body weight gain, and decreased serum triglyceride and insulin levels. Inhibition of ACOX1 is a novel and effective approach for the treatment of high fat diet- or obesity-induced metabolic diseases by improving mitochondrial lipid and ROS metabolism.