Acetylenic Esters Research Articles

Electrochemical Esterification Reaction of Alkyne Aldehyde with Alcohols Mediated by Carbene and Iodine

A new type of alkyne esterification was developed under electrochemical conditions using alkyne aldehydes and alcohol compounds as starting materials and carbene and iodine as mediators. Through this method, external oxidants and transition metals are excluded and the alkyne bond is fully preserved. This approach is compatible with a wide range of substrates and various functional groups and provides a green and mild new route for directly converting alkyne aldehydes into alkyne esters.

Efficient generation of novel phosphorus ylides via chemoselective and chemospecific reactions utilizing 2-(arylamino)-2-thioxoacetamide and methyl benzoylglycinates as precursors with activated acetylenic compounds

A chemospecific and chemoselective procedure has been developed for the efficient synthesis of novel phosphorus compounds, achieving moderate to excellent yields. This method involves the reaction of 2-(arylamino)-2-thioxoacetamide and methyl benzoylglycinate precursors with PPh3 in the presence of activated acetylenic esters. Notably, the reaction exhibits superior selectivity toward the NH2 group in 2-(arylamino)-2-thioxoacetamide, rather than the NH group. Moreover, when methyl benzoylglycinates are employed as a precursor, the reaction yields two distinct families of ylides, each with its own unique percentage yield.

Green synthesis and cytotoxic activity of functionalized naphthyridine.

A multicomponent synthesis of 1,8-naphthyridine with high yields utilizing benzaldehydes, malononitrile, phenol, and acetylenic esters in aqueous solution at room temperature in the presence of SiO2/Fe3O4 as a reusable catalyst is reported. Using the MTT test, the cytotoxic properties of all the produced compounds were assessed in vitro against cancer cell lines (MCF-7 and A549) and normal cell lines (BEAS-2B). It was discovered that the most effective cytotoxic agent, doxorubicin-like in its lack of selectivity, was the derivative 5h. On the other hand, the compound 5c might be regarded as an equipotent molecule with greater selectivity in relation to doxorubicin. Also, this study investigates the antioxidant effects of 1,8-naphthyridine carboxylates, along with other studies conducted in this study.

Flash vacuum pyrolysis of steroid esters

We report here our synthetic approach to acetylenic esters of six different steroids. The use of flash vacuum pyrolysis (FVP) is a very appealing tool for the acetylenic moiety to efficiently cyclize and rearrange which allows access to medicinally and pharmaceutically valuable products. Each substrate was subjected to FVP. The products were analyzed, identified and characterized. Acetylenic esters of aromatic steroids resulted in 2H-cyclohepta[b]furan-2-one, and 2H-chromen-2-one derivatives, while aliphatic esters afforded unsaturated polycyclic hydrocarbons via elimination of propiolic acid.

Synthesis of novel organophosphorus compounds via reaction of substituted 2-oxoindoline-3-ylidene with acetylenic diesters and triphenylphosphine or triphenyl phosphite

An efficient reaction between triphenylphosphine or triphenyl phosphite and 2-oxoindoline-3-ylidene derivatives in the presence of acetylenic esters leads to functionalized 2-oxoindoline-3-ylidene containing phosphorus ylieds or phosphonate esters. All compounds obtained in these reactions are stable and have good yields.

Hydrophobic eutectic and hydrophilic melts of gabapentin-lactam & citric acid mixtures; green promoters for selective synthesis of xanthenes/ benzo[b]pyrans and dihydropyrroles

Gabapentin-lactam and citric acid form a glassy hydrophobic deep eutectic mixture. Certain non-eutectic molar ratios of the two components are also low-melting mixtures and slight differences can be discerned in their differential calorimetric curves. Yet, they impose different selective promotions on the reaction of malononitrile, arylaldehyde, and dimedone. Interestingly, the reaction mixture selectively gives tetrahydrobenzo[b]pyran-2H-ones or 1,8-dioxo-octahydroxanthenes depending on being carried out in the melted 2/1 or 1/2 molar mixtures of gabapentin-lactam/citric acid. An excellent promoting activity was also observed for the melt of gabapentin-lactam and citric acid mixture in 1/1 molar ratio. This melt proved to be an efficient promoter for synthesis of 4‑hydroxy-2,5-dihydropyrrol-5-ones from the domino reaction of an arylaldehyde, an aniline derivative, water, and an acetylenic ester. No additional organic solvents are required to perform the reactions and the bio-compatible melts can be reused several times after easy separation from the products. The eutectic and the non-eutectic melts preserve their viscous liquid state even upon a long-term storage at ambient temperature.

Flash vacuum pyrolysis of aspirin, paracetamol, and their derivatives and analogues

Synthesis and flash vacuum pyrolysis (FVP) of acetylenic esters and ethers of paracetamol and aspirin and their analogues were performed. The products were analyzed, identified, and characterized. Acetylenic esters and ethers of paracetamol resulted in benzofuran, and cyclohepta[b]pyrrol-2(1H)-one. Aspirin and its derivatives produced chromenones, xanthones, indenones, chromenes, and other heterocyclic compounds.

An efficient one-pot synthesis of highly functionalized selenophenes

The reaction between active alkenes such as 2-pyridin-2-yl-methylene-malononitrile or ethyl-2-cyano-3-pyridin-2-yl-acrylate and acetylenic esters in the presence of KSeCN at room temperature provided a simple and efficient one-pot route for the synthesis of highly functionalized selenophenes. The reaction is characterized by mild conditions, short reaction time and tolerance to various functional groups and the products were fully characterized by multinuclear (1H, 13C, and 77Se) NMR spectroscopy.

Ag/KF/CP@MWCNTs Catalyzed Green Synthetic Pathway for Bio-Active New Thiazolopyrimidines and Oxazolopyrimidines

In this paper, thiazolo[3,2-a]pyrimidine-2,3-dicarboxylate and oxazolo[3,2-a]pyrimidine-2,3-dicarboxylate derivatives are produced in excellent yields via the multicomponent reaction of anilines, ethyl acetoacetate, aldehydes, urea or thiourea, activated acetylenic esters and triphenylphosphine in the presence of Ag/KF/CP@MWCNT as a high efficient catalyst in aqueous media at ambient temperature. The Ag/KF/CP@MWCNT is generated by water extract of rhizome Petasites hybridus as an environmentally media and moderate base. Also, Ag/KF/CP@MWCNT leads to increasing of yield of products and has notable reusability. Antioxidant ability of the resulted compounds is studied by DPPH (radical trapping of diphenyl-picrylhydrazine) and ferric reduction power tests. Also, the antimicrobial activity of some products is determined with the disk diffusion experiment on Gram-positive and Gram-negative bacteria. The advantages of this protocol include of short reaction time, high efficiency and easy separation of products and use of simple catalyst. HIGHLIGHTS Green chemistry is the use of a set of principles to reduce or eliminate the use or generation of unsafe materials in the design, fabrication and applications of chemical products. Among solvents, water is a green solvents and very suitable for performing organic reaction. The present procedure avoids the use of toxic solvent. Compounds bearing fused thiazole and pyrimidine units play important role in organisms because they have good biological potentials. Thiazolopyrimidines are an interesting group of heterocyclic compounds and among them the thiazolo[3,2-a]pyrimidine skeleton are a key constructions and have vital biological activities and are widely found in important drugs such as Alzheimer’s disease, anticancer, antimicrobial, anti-inflammatory, antioxidant, anti-human cytomegalovirus activity, antiparkinsonian, antitumor and antiviral.

Neat multicomponent assembly of highly functionalized Acenaphtho[1,2‐b]pyrroles, in vitro evaluation for antioxidant and cytotoxic activities

AbstractA facile one‐pot multicomponent route for the synthesis of acenaphtho[1,2‐b] pyrroles from acenaphthenequinone using amines and activated alkynes is reported. The method involves the formation of a zwitterionic intermediate through Huisgen dipolar cycloaddition reaction of amines and activated alkynes. The solvent free method was found to be superior than conventional methods in terms of reaction resulted in excellent yields in the presence of electron releasing and halogen containing substituents on the primary aromatic amine and on altering the alkyl substituents of the acetylenic ester. Antioxidant activity of the titled derivatives (4a‐j) was investigated by the Diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging method. Compounds 4b and 4j showed relative radical scavenging potential comparable to that of ascorbic acid (IC50 = 25.20 μg/mL). Cell growth inhibition testing was carried out using 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyl tetrazolium bromide (MTT) assay in two different human cancer cell lines colon (HT‐ 29) and breast (MCF‐7). Compound 4j is comparatively effective against HT‐29 cells (GI50 = 23.6 ± 0.11) in comparison with standard 5‐FU (GI50 = 25.5 ± 0.29) and also moderately effective against MCF‐7 cells (GI50 = 10.3 ± 0.12) in comparison with standard Doxorubicin (GI50 = 2.6 ± 0.06) among the other evaluated derivatives. The results revealed the promising lead compounds 4j for further optimization toward the discovery and development of new anti‐cancer agents.

Oxa-Michael Addition Reactions of 3-hydroxy-2-azetidinones: Synthesis of 1, 3, 4-Trisubstituted-2-Azetidinones

Abstract:The manuscript describes a facile and an efficient methodology for the synthesis of 1, 3, 4 trisubstituted-β-lactams by base mediated oxa-Michael addition reactions of 3-hydroxy-2- azetidinones with acetylenic esters under different reaction conditions. These functionalized 1, 3, 4-trisubstituted-azetidin-2-ones are useful organic synthons for the synthesis of various heterocyclic compounds having diverse pharmacological applications.

Acetylenic Esters in Organic Synthesis

AbstractActivated acetylenic substrates such as acetylenic esters and alkyl propiolates are very important in organic synthesis. Due to their electron deficiency, these compounds are widely used in combinatorial and multicomponent reactions, enabling the synthesis of a large variety of novel compounds. In addition, these substrates are powerful Michael acceptors and convenient dienophiles and dipolarophiles in Diels–Alder and 1,3-dipolar cycloaddition reactions. The addition of different nucleophiles, primarily phosphorus, nitrogen or sulfur, to the triple bonds of these substrates produces key intermediates, such as Tebby and Huisgen zwitterions, which can lead to designing pathways toward the generation of spirocyclic and polycyclic compounds. This account highlights recent studies on the chemistry of acetylenic esters and their applications in organic synthesis.1 Introduction2 Synthesis of Acyclic and Monocyclic Compounds3 Synthesis of Spirocyclic Compounds4 Synthesis of Polycyclic Compounds5 Conclusion

Reactivity of pyrimidinylphosphazenes with acetylenic esters: Competitive [4 + 2] and [2 + 2] tandem cycloaddition or retro‐cycloaddition approaches

AbstractIn the search for new intermediates for heterocyclic synthesis, the reactivity of 6‐iminophosphoranepyrimidines against dimethyl acetylenedicarboxylate (DMAD) and ethyl propiolate as dienophiles, was studied in this work. The presence of a viable 2‐azadienic moiety in pyrimidin‐4‐one rings (oxo derivatives) favored reaction of DMAD by [4 + 2]/retro‐[4 + 2] sequence, in addition to the expected [2 + 2] cycloaddition/retrocycloaddition involving phosphazene moiety. In contrast, pyrimidine derivatives lacking a viable 2‐azadienic residue reacted only through phosphazene group by the aforementioned [2 + 2]/retro‐[2 + 2] tandem process. Ethyl propiolate (non‐symmetric dienophile) proved less reactive in the study, giving rise to undesired side reactions.

CHEMICAL MODIFICATION OF NAFTALINE-1-IL-BIS(SODIUM CARBAMODITHIOATE)

Interest in numerous naphthylamine derivatives is due to a wide range of their biological activity (growth-stimulating, antimicrobial, anticancer, antiviral, antihypertensive, antidiabetic, etc.). The aim of the workis the synthesis of biologically active N,S,O-containing substances in the series of acetylenic, alkoxy- and aroxyalkyl esters of naphthylamine. Study of acylation, propargylation and alkylation reactions of naphthalene-1-yl-bis(sodium carbamodiothioate). Methodology. New derivatives of naphthylbisdithiocarbamic acid were synthesized as a result of the modification of disubstituted α-naphthylaminedithiocarbamate. It was shown that the interaction of α-naphthylaminebisdithiocarbamate with benzoic acid chloride, propargyl bromide and alkyl halides (2-methoxyethyl, 2-ethoxyethyl, 2-phenoxyethyl, 3-phenoxypropyl) leads to the formation of the corresponding thioanhydride, dithioacetylenic, alkoxy- and aroxyalkyl esters of naphthylbisdithiocarbamic acid. Synthesis was carried out in acetone at room temperature for 1.5 – 3 h. Reaction coursewas monitored by TLC method. Results and discussion. It was established that propargylation, acylation and alkylation reactions of α-naphthylaminedithiocarbamine derivative proceed easily and with high yields (66 − 91%). The structure of the synthesized compounds was established based on the data of elemental analysis and 1H and 13C NMR spectroscopy. Thus, were synthesized new potentially biologically active naphthylbisdithiocarbamic acid derivatives, combining pharmacophore groups in their structure.

IRMOF-3 Functionalized GO/CuFe2O4: A New and Recyclable Catalyst for the Synthesis of Dihydropyrano[2,3-c]Pyrazoles under Ultrasound Irradiations

In the present study, we reported a facile and cost-effective method for synthesizing magnetic copper ferrite nanoparticles supported on IRMOF-3/GO [IRMOF-3/GO/CuFe2O4]. The prepared IRMOF-3/GO/CuFe2O4 was completely characterized by various spectroscopic techniques such as Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric (TGA), energy-dispersive X-ray spectroscopy, and elemental meapping. The synthesized nanocatalyst demonstrated high catalytic activity in the synthesis of dihydropyrano[2,3-c]pyrazoles via a one-pot reaction of hydrazine hydrate, acetylene ester, aryl aldehydes, and malononitrile exposed to ultrasound irradiations. In comparison to formerly reported approaches, this protocol has various advantages including wide substrate compatibility, short reaction times, excellent yields, little catalyst loading, good reusability, and high efficiency. The catalyst was separated by simple filtration and after several rounds of reuse and recovery, the amount of activity in this catalytic system remained nearly constant.

Solvent-free synthesis of new spiropyrroloindole compounds using Fe3O4/TiO2/MWCNTs MNCs via multicomponent reactions: assessment of new spiropyrroloindole antioxidant activity.

In this study, water extract of Spinacia oleracea leaves was used for the synthesis of Fe3O4/TiO2/MWCNTs magnetic nanocomposites and high performance of this catalyst was confirmed by employing it in the solvent-free multicomponent reactions of anilines, oxalyl chloride, diamines or hydroxyamines, electron-deficient acetylenic ester, α-haloketones and Et3N at room temperature for the generation of new spiropyrroloindoles in high yields. This catalyst could be utilized several times and has a significant role in the yield of product. The synthesized spiropyrroloindoles have NH and OH group in their structure and for this reason have good antioxidant activity. Also, by employing Gram-positive and Gram-negative bacteria and the disk diffusion procedure confirmed the antimicrobial effect of some spiropyrroloindole derivatives. The results showed that synthesized spiropyrroloindoles prevented the bacterial growth. This used process for preparation of new spiropyrroloindoles has some improvements such as low reaction time, product with high yields, and simple separation of catalyst and products.

Synthesis and evaluation of antioxidant and antimicrobial activity of new spiropyrrolopyrrolizine compounds: Using Fe3O4/TiO2/Multiwall carbon nanotubes (MWCNTs) magnetic nanocomposites

In this research, we synthesized the Fe3O4/TiO2/multiwall carbon nanotubes (MWCNTs) magnetic nanocomposites using water extract of Spinacia oleracea leaves, and the high performance of synthesized catalyst was confirmed by employing of it in the multicomponent reaction of reaction of isatoic anhydride, tert‐butylisocyanide, diamines, or hydroxyamines, electron‐deficient acetylenic ester, α‐haloketones, and Et3N in water at ambient temperature for the production of new spiropyrrolopyrrolizine compounds in high yields. This catalyst could be used several times in these reactions and have main role in the yield of product. The synthesized compounds have NH and OH group in their structure and, for this reason, have good antioxidant activity. Also, employing Gram‐positive and Gram‐negative bacteria in the disk diffusion procedure confirmed the some spiropyrrolopyrrolizine derivatives antimicrobial effect. The results showed that synthesized compounds prevented the bacterial growth. This used procedure for preparation of spiropyrrolopyrrolizine derivatives have some advantages such as low reaction time, product with high yields, and simple separation of catalyst and products.

Polyaddition Synthesis Using Alkyne Esters for the Design of Vinylogous Urethane Vitrimers

Vitrimers are a subclass of covalent adaptable networks which introduce reshapeability and recyclability in thermoset materials while maintaining a high degree of chemical resistance and dimensional stability. Vitrimer materials based on vinylogous urethane (VU) chemistry have drawn a lot of attention in this area. Classically, these are obtained by the polycondensation polymerization of acetoacetate and amine monomers. Unfortunately, this also releases water, often leading to porosity defects in the initially obtained non-reprocessed cross-linked materials. Here, we demonstrate that alkyne esters (AE) can be used as alternative building blocks for VU vitrimers by a polyaddition polymerization with amines, leading to water-free formulations and straightforward access to defect-free cured VU vitrimer materials. The bond formation and dynamic bond exchange was also studied by small molecule reactions, further rationalized by a computational (DFT) approach. The resulting water-free VU vitrimers display similar material properties compared to vitrimers based on acetoacetates, although also some differences are seen, which can be related to a minor amide-bond forming side reaction. Furthermore, by use of this novel AE approach, polyaddition curing of VU epoxy vitrimers can easily be prepared in a one-pot three-component method, combining AE, amine, and epoxy monomers. This study shows that AE monomers can be used as an easy drop-in method to obtain processable epoxy materials with tunable viscoelastic properties, where the viscous flow behavior can in principle be fully tuned by varying the monomers’ ratios and compositions.

Formation and Cycloaddition Reactions of a Reactive Boraalkene Stabilized Internally by N‐Heterocyclic Carbene

AbstractThe synthesis of element−carbon double bonds is of great importance for the development and understanding of reactive π‐bonded systems in chemistry. The seven‐membered heterocyclic system 4 b is readily made by internal C−H activation at a pendent isopropyl methyl group of the respective [(IPr)C6F5BH]+ borenium ion. Subsequent deprotonation with the IMes carbene gives the neutral cyclic boraalkene system 5 b. The B=C double bond in compound 5 b adds carbon dioxide, CS2, sulfur dioxide, phenyl isocyanate, an acetylenic ester or two NO molecules to give the corresponding four‐membered ring annulated heterocycles. With sulfur or selenium 5 b gives the respective three‐membered ring systems. N2O reacts with 5 b to give a mixture of the related oxaborirane 18 and a unique [B]OH containing diazoalkane product 19.

Formation and Cycloaddition Reactions of a Reactive Boraalkene Stabilized Internally by N-Heterocyclic Carbene.

The synthesis of element-carbon double bonds is of great importance for the development and understanding of reactive π-bonded systems in chemistry. The seven-membered heterocyclic system 4 b is readily made by internal C-H activation at a pendent isopropyl methyl group of the respective [(IPr)C6 F5 BH]+ borenium ion. Subsequent deprotonation with the IMes carbene gives the neutral cyclic boraalkene system 5 b. The B=C double bond in compound 5 b adds carbon dioxide, CS2 , sulfur dioxide, phenyl isocyanate, an acetylenic ester or two NO molecules to give the corresponding four-membered ring annulated heterocycles. With sulfur or selenium 5 b gives the respective three-membered ring systems. N2 O reacts with 5 b to give a mixture of the related oxaborirane 18 and a unique [B]OH containing diazoalkane product 19.