Reaction Of Salicylaldehyde Research Articles

Glycerol and acetic acid assisted mild strategy for facile synthesis of 3-heteroarylcoumarins via three-component reaction

A feasible and inexpensive reaction system for synthesis of 3-benzoxazol-2-yl-chromen-2-one as a kind of 3-heteroarylcoumarins has been developed. Both acetic acid and glycerol are simple, cheap and common chemicals, the combination of them could smoothly accelerate the three-component one-pot reaction of salicylaldehyde, o-aminophenol and ethyl cyanoacetate to yield 3-heteroarylcoumarins. This process not only offers the products in good to excellent yields but also avoids the problems associated with catalyst cost, handling, safety and pollution. Compared with the literature, the reaction temperature successfully reduced to 80 °C. As an application, disperse yellow 232 was furnished with a satisfactory yield under optimum reaction conditions. In addition, all synthesized 3-heteroarylcoumarins were preliminary evaluated the inhibitory effect against human carboxylesterase 1. This protocol offers an expedient strategy for efficient synthesis of 3-heteroarylcoumarins that are widely present in biologically active compounds and fluorescent paints.

Functional substituted Cu(II) Schiff base complexes, syntheses, X-ray and theoretical characterizations, and investigations of their polyphenol oxidase- and peroxidase-like activities

Some Cu(II) Schiff base complexes were synthesized by a template reaction of salicylaldehyde and amino ethanol or aminoethoxyethanol with Cu(OAc)2.H2O in methanol solution as the model compounds for mimic enzymatic activities. The synthesized bidentate ligands were formed one chelate ring via iminic N and phenolic O donor atoms. The resulting complexes were characterized by elemental analysis and FTIR spectroscopy. The FTIR spectra of the complexes showed typical changes for Schiff base coordination when comparing with the FTIR spectrum of the ligand. The molecular and crystal structures of bis (2-((2-hydroxybenzylidene)amino)ethyl acrylate) copper(II), ([Cu(SAE-Acr)2]) compound were clarified by single crystal X-ray diffraction technique. In order to visualize the intermolecular interactions in the crystal of the [Cu(SAE-Acr)2] compound, a Hirshfeld surface (HS) analysis was carried out, and the intermolecular interaction energies were also calculated using the CE–B3LYP/6–31G(d,p) energy model. Polyphenol oxidase and peroxidase-like activities of the synthesized compounds were also investigated. The results showed that Cu(SAE)2 and Cu(SAE-Acr)2 compounds had good polyphenol oxidase and peroxidase-like activities.

Catalyst-free Synthesis of Aminomethylphenol Derivatives in Cyclopentyl Methyl Ether via Petasis Borono-Mannich Reaction.

Aminomethylphenol molecules have wider applications in pharmaceuticals, agrochemicals, plant protection and promising functional materials. The development of an efficient and practical method to prepare this class of compound is highly desirable from both environmental and economical points of view. In order to establish an effective synthetic method for preparing aminomethylphenol derivatives, the Petasis borono-Mannich reaction of salicylaldehyde, phenylboronic acid and 1,2,3,4- tetrahydroisoquinoline was selected as a model reaction. A variety of reaction conditions are investigated, including solvent and temperature. The generality and limitation of the established method were also evaluated. It was found that model reaction can be carried out in cyclopentyl methyl ether at 80 oC under catalyst-free conditions. This protocol, with broad substrate applicability, the reaction of various arylboronic acid, secondary amine and salicylaldehyde proceeded smoothly under optimal reaction conditions to afford various aminomethylphenol derivatives in high yields. A practical, scalable, and high-yielding synthesis of aminomethylphenol derivatives was successfully accomplished. A catalyst-free practical method for the synthesis of minomethylphenol derivatives based on Petasis borono-Mannich (PBM) reaction of various arylboronic acid, secondary amine and salicylaldehyde in cyclopentyl methyl ether has been developed. The salient features of this protocol are avoidance of any additive/catalyst and toxic organic solvents, use of cyclopentyl methyl ether as the reaction medium, clean reaction profiles, easy operation, and high to excellent yield.

The Electrical Conductivty Of Fe-Chitosan Schiff Base Complex

High electrical conductivity material Fe-Chitosan Schiff base produced via two stages mechanism, reaction of salicylaldehyde and chitosan in three necked flask following the formation of complex by soak Chitosan Schiff base in FeCl3 solution in various times. The formed Schiff base was confirmed by presence of imine at 1604.77 cm-1. Next, Fe absorption was analyzed by using ICP-MS gives highest results at 492,51 ppm at 5 hours immersion time. The electrical conductivity exhibit tendency to increase and the highest point at 3.5 x 10-6 S cm­-1

ZnCl2 catalyzed new coumarinyl-chalcones as cytotoxic agents.

A new series of coumarin-yl-chalcone derivatives (3a-m) had been designed and synthesized through different reactions such as aromatic addition, cyclization and Claisen-Schmidt reactions in good yields (54–78%). 5-acetyl-4-(2-hydroxyphenyl) -6-methyl-3, 4-dihydropyrimidin-2(1H) -one (1) has been synthesized by multi-component one pot reaction of salicylaldehyde, methyl acetoacetate and urea, which was further reacted with malonic acid employing ZnCl2 catalyst to yield 5-acetyl-4-(4-hydroxy-2-oxo-2H-chromen-8-yl) -6-methyl-3, 4-dihydropyrimidin-2(1H) -one (2). The title compounds (3a-m) were synthesised by reacting 5-acetyl-4-(4-hydroxy-2-oxo-2H-chromen-8-yl) -6-methyl-3, 4-dihydropyrimidin-2(1H)-one (2) with different aromatic aldehydes in the presence of potassium hydroxide. In silico studies, a preliminary screening method for predicting the anti-cancer activity was performed for the synthesized compounds (3a-m) against Src, Alb tyrosine kinase and homology model protein (PDB ID: 4csv). The derivatives 3h and 3m showed moderate binding energies. The in vitro cytotoxic activity was evaluated for the compounds 3h and 3m by using human cancer cell-line morphology and MTT assay against three human cell-lines A549 (Lung), Jurkat (Leukemia) and MCF-7 (Breast). The results indicate that the derivatives 3h and 3m display significant anti-cancer activity, however it was found to be less cytotoxic when compared to the standard used i.e. Imatinib.

Synthesis, characterization, photo physical and DFT studies of bicoumarin and 3-(3-benzofuranyl)coumarin derivatives

• A series of novel bicoumarin and 3-(3-benzofuranyl)coumarin derivatives are synthesized. • Optical band gaps of the synthesized compounds were found to be 2.80–3.87 eV. • The 5% weight loss of derivatives is in the range of 239–367 °C. • The synthesized compounds are thermally stable. A series of novel bicoumarin and 3-(3-benzofuranyl) coumarin derivatives were synthesized by the reaction of salicylaldehyde and substituted coumarin 4-acetic acid/benzofuran-3-acetic acid using cyanuric chloride. The scaffolds were characterized by spectral analysis. The significant photophysical fundamentals for organic electronic applications such as thermal stability, strong and broad optical absorption were investigated for the synthesized compounds. Optical properties are studied in detail by UV-Vis absorption and fluorescence spectroscopy. Optical band gaps of the bicoumarin and 3-(3-benzofuranyl)coumarin derivatives were found to be 2.80–3.87 eV as calculated from their onset absorption edge. The bicoumarin and 3-(3-benzofuranyl)coumarin derivatives exhibit high thermal stability up to 239–367 °C. Density functional theory computation was performed to understand intramolecular charge transfer property. Photophysical studies designate that, the synthesized materials are potential candidates and play an important role in organic electronic applications.

Monitoring of reduction reaction of 2-((phenylimino)methyl)phenol compound with sodium borohydride in solution by infrared spectroscopy

In this study, an imine compound 2-((phenylimino)methyl)phenol was synthesized by the reaction of salicylaldehyde and aniline for in situ monitoring of reduction with sodium borohydride. The reduction of C = N double bond to C–N in solution was continuously monitored by infrared spectroscopy using the background defining method in liquid cell at ambient temperature. The structures of the purified 2-((phenylimino)methyl)phenol compound and the resulting 2-((phenylamino)methyl)phenol compound were elucidated by Infrared Spectroscopy, H1 and C13 Nuclear Magnetic Resonance Spectroscopy.

A novel selective “turn-on’’ fluorescent sensor for Hg2+ and its utility for spectrofluorimetric analysis of real samples

A novel anthracene-based dipodal Schiff base ‘‘turn-on’’ fluorescent sensor (FS) was designed and synthesized by accessible and straightforward Schiff base reaction of salicylaldehyde and 9,10-bis(aminomethyl)anthracene with high yield. The chemical characterization of fluorescent sensor FS was performed by standard spectroscopic techniques (MALDI-MS, FT-IR, 1H, and 13C NMR), and photophysical properties were exanimated by UV-vis and fluorescent spectroscopies. The fluorescent sensor FS can coordinate with Hg2+ via Schiff base moiety when analytical signal as a “turn on” fluorescent response was obtained via anthracene moiety after coordination. Also, spectrofluorimetric analysis of Hg2+ was carried out using fluorescent sensor FS in environmental water samples after optimization required experimental conditions such as pH, the time before measurements, and photostability. According to obtained results, the presented fluorescent sensor can be used for selective and sensitive spectrofluorimetric determination of Hg2+.

Catalyst-Solvent System for PASE Approach to Hydroxyquinolinone-Substituted Chromeno[2,3-b]pyridines Its Quantum Chemical Study and Investigation of Reaction Mechanism.

The Pot, Atom, and Step Economy (PASE) approach is based on the Pot economy principle and unites it with the Atom and Step Economy strategies; it ensures high efficiency, simplicity and low waste formation. The PASE approach is widely used in multicomponent chemistry. This approach was adopted for the synthesis of previously unknown hydroxyquinolinone substituted chromeno[2,3-b]pyridines via reaction of salicylaldehydes, malononitrile dimer and hydroxyquinolinone. It was shown that an ethanol-pyridine combination is more beneficial than other inorganic or organic catalysts. Quantum chemical studies showed that chromeno[2,3-b]pyridines has potential for corrosion inhibition. Real time 1H NMR monitoring was used for the investigation of reaction mechanism and 2-((2H-chromen-3-yl)methylene)malononitrile was defined as a key intermediate in the reaction.

Synthesis and characterization of new 4H-chromene-3-carboxylates ensuring potent elastase inhibition activity along with their molecular docking and chemoinformatics properties.

A new series of 4H-chromene-3-carboxylate derivatives were synthesized using multicomponent reaction of salicylaldehyde, ethyl acetoacetate and dimedone in ethanol with K3PO4 as a catalyst at 80°C. The structures of all newly synthesized compounds were confirmed by spectral techniques viz. IR, 1H NMR, 13C NMR, and LCMS analysis. The newly synthesized compounds 4a to 4j were screened against elastase enzyme. Interestingly, all these compounds found to be potent elastase inhibitors with much lower IC50 value. The compound 4b was found to be most potent elastase inhibitor (IC50=0.41±0.01µM) amongst the synthesized series against standard Oleanolic Acid (IC50 value=13.45±0.0µM). The Kinetics mechanism for compound 4b was analyzed by Lineweaver-Burk plots which revealed that compound inhibited elastase competitively by forming an enzyme-inhibitor complex. Along with this, all the synthesized compounds (4a - 4j) exhibits excellent DPPH free radical scavenging ability. The inhibition constant Ki for compound 4b was found to be 0.6µM. The computational study was comprehensible with the experimental results with good docking energy values (Kcal/mol). Therefore, these molecules can be considered as promising medicinal scaffolds for the treatment of skin-related maladies.

An Extensive Study of Coumarin Synthesis via Knoevenagel Condensation in Choline Chloride Based Deep Eutectic Solvents.

In order to preserve the environment from harmful organic solvents, a synthesis of coumarin derivatives was performed in deep eutectic solvents, which are considered as "green" due to their characteristics. Choline chloride based deep eutectic solvents (DESs) were employed, both as solvents and as catalysts, in the synthesis of coumarin derivatives via Knoevenagel condensation. In order to find the best DES for coumarin synthesis, 20 DESs were tested for the reaction of salicylaldehyde and dimethyl malonate at 80 °C. Among the twenty tested deep eutectic solvents only five were adequate for this kind of synthesis. The best DES for this reaction was found to be the one composed of choline chloride:urea (1:2). Most coumarin compounds were obtained in good to excellent yield. Compounds 1g, 2g and 2p should be pointed out due to their yields of 85, 88 and 98 %, respectively. 3-Acetylcoumarins 5a, 5c, 5d, 5e, 5f and 5g were synthesized under ultrasound irradiation and were also obtained in excellent yields of 90, 95, 98, 93, 94 and 85 %, respectively. Series of coumarin derivatives were successfully synthesized, either in choline chloide:urea DES at 80 °C or in ultrasound-assisted reaction, from different salicylaldehydes and active methylene compounds. These "green" methods were found to be very effective in Knoevenagel condensation, while DES was recycled for several cycles without any significant influence on the product yield.

New insight into experimental and theoretical mechanistic study on a green synthesis of functionalized 4H‐chromenes using magnetic nanoparticle catalyst

AbstractA green synthesis of functionalized 4H‐chromenes using one‐pot, three‐component reaction of salicylaldehyde (1), active methylene (2), and carbon‐based nucleophile (3) using Fe3O4@CONa nanoparticles in water has been performed at 60°C. The Fe3O4@CONa nanoparticle as an efficient, green, and magnetically reusable heterogeneous catalyst was applied in these reactions up to the nine runs. Green catalyst and solvent, short reaction time, high product yields, as well as simple work‐up procedure were found as some advantages of this methodology. The density functional theory calculations were applied to all‐inclusive perception of the one‐pot, three‐component reaction mechanism. The most reactions progressed through the following route: (a) nucleophilic addition of 2 to 1; (b) ring closing, dehydration; (c) nucleophilic substitution of 3 (2‐naphtol, 4‐hydroxycumarin) to intermediate. Sometimes mechanism mutated to: (a) nucleophilic addition of 3 (indole, 2‐methylindole) to 1, and dehydration; (b) nucleophilic addition of 2 to intermediate; and (c) ring closing, and dehydration. The frontier molecular orbitals, NBO analyses, molecular electrostatic potential of reactants, and intermediates confirmed the proposal mechanisms. Theoretical study could be so helpful to pick out suitable reactants of the reaction.

Novel synthesis of oxoacetamides via reaction of salicylaldehyde and isocyanide under mild reaction condition

A convenient procedure for the formation of oxoacetamides derivatives is reported via the reaction of salicylaldehyde and alkyl isocyanide in a simple process without the use of any catalyst or metal promoters in DCM at room temperature. The structure of all obtained derivatives were determined by elemental and spectral analyses. In this reaction, 1,3-dioxine-4,4-dicarboxamide was obtained as minor product. This process offers considerable advantages such as the simplicity of reaction, regioselectivity, and the use of commercially available materials.

Mild and efficient prepare disperse yellow 184, disperse yellow 232 and their analogues via LTTM promoted three-component reaction

A convenient protocol for the synthesis of disperse yellow 184, disperse yellow 232 and their analogues via a three-component one-pot reaction of salicylaldehyde, o-aminophenol and ethyl cyanoacetate has been established. Cheap and eco-friendly ethanol was employed as solvent. One drop of low-transition-temperature mixture (LTTM) which formed from l(−)-Proline and oxalic acid could smoothly promote the reaction of 0.5 mmol raw materials. Compared to the classical methodologies, the present pathway has broad reaction scope and affords all products in good to excellent yields. Furthermore, this process could reduce the reaction temperature from 135 to 85 °C and avoid the problems associated with catalyst cost, handling, safety and pollution. On the basis of comparative experiments and DFT calculation, possible mechanism of this strategy is discussed in detail.

New Zn(II) Complexes of Substituted bis(Salicylidene)phenyl-1,2-diamino Based Organic Ligands: Synthesis, Photoluminescence, Applications in Forensic Fingerprint and Dye Sensitized Solar Cells

New azomethine-Zn(II) complexes of bis(salicylidene)phenyl-1,2-diamino organic ligand derivatives were synthesized by the reaction of salicylaldehyde, substituted phenyl-1,2-diamine with zinc acetate. The synthesized complexes were characterized by FTIR, 1H NMR and EDS. Their photophysical and electrochemical properties were studied and their applicability for dye-sensitized solar cells (DSSCs) and forensic finger print developments have been demonstrated. Photoluminescence studies revealed that the emission peaks of the complexes in solution state appeared at 372-406 nm and emitted blue light. Latent fingerprint detection study indicated that the powder compounds show good adhesion and finger ridge details without back ground staining. Based on these results, it was ascertained that these Zn(II) complexes can serve as a suitable non-dopant blue light emitting compound for flat panel display applications and applied to detect fingerprints on all types of smooth surfaces.

Copper-catalyzed cascade three-component azide–alkyne cycloaddition/condensation/transesterification: easy access to 3-triazolylcoumarins

A novel and efficient strategy has been developed for the synthesis of 3-triazolylcoumarins in a one-pot, copper-catalyzed multicomponent reaction involving a cascade reaction of salicylaldehydes, ethyl 2-azidoacetate, and arylacetylenes.

Domino Reaction of Aromatic Aldehydes and 1,3-Indanediones for Construction of Bicyclo[2.2.2]octanes and Dibenzo[b,g]indeno[1',2':3,4]fluoreno[1,2-d]oxonines.

Triethylamine promoted the pseudo-five-component reaction of aromatic aldehyde with four molecules of 1,3-indanediones in refluxing ethanol to give unique polycyclic bicyclo[2.2.2]octane derivatives containing bridged- and spiro-indanone scaffolds in good yields. The mechanistic studies supported that the reaction included base-catalyzed cyclotrimerization of 1,3-indanedione to give an active cyclic diene and the sequential Diels-Alder reaction with in situ generated 2-arylidene-1,3-indanediones as electron-deficient dienophiles. On the other hand, the pseudo-four-component reaction of salicylaldehyde with 1,3-indanedione afforded the dibenzo[b,g]indeno[1',2':3,4]fluoreno[1,2-d]oxonines in high yields. This reaction clearly demonstrated the high efficiency, molecular convergence, atom-economy, and impressive selectivity of multicomponent reactions.

Uptake of Metal Ions (Co(II) and Ni(II)) by Silica-Salicylaldehyde Derived from Rice Husks

The source of silica in silica-salicylaldehyde was rice husk ash (RHA). RHA was converted to sodium silicate by reacting with sodium hydroxide solution. The technique of sol–gel was used to synthesize RHAPrNH2 through the reaction of 3-(aminopropyl)triethoxysilane with sodium silicate in a strong acidic medium. Novel nanomaterial (RHA-SALED) was prepared from the reaction of salicylaldehyde with RHAPrNH2 by condensation reaction in toluene solvent. The technique of FTIR showed that the peak at 1622 cm−1 belongs to C=N. XRD technique showed the amorphous nature for RHA-SALED with maximum intensity at 22° (2θ). CHNS technique proved that RHA-SALED contain 9.28% of N higher than that of RHAPrNH2. SEM confirmed that the functionalized particles are granular and shaped irregularly with a common diameter of ca. 40.36 nm. BET measurements additionally confirmed that the surface place is 1.0356 m2 g−1 of RHA-SALED with pore size distribution 10.879 nm. The material RHA-SALED was used for absorption from an aqueous solution of heavy contaminating metal ions Ni(II) and Co(II).

A coumarin-based turn-on chemosensor for selective detection of Zn(II) and application in live cell imaging.

A 2-oxo-2H-chromene-3-carbohydrazide (CHB) was synthesized by the reaction of salicylaldehyde with diethyl malonate and hydrazine hydrate. The recognition behaviors of CHB to Zn2+ were investigated and the results showed that CHB exhibits well selectivity and sensitivity to Zn2+ with fast response in PBS (pH = 7.24, 60% DMF), the co-existed cations and anions could not interfere the recognition between CHB and Zn2+. Besides, the detection limit of CHB for Zn2+ was calculated to be 0.95 μM. Furthermore, DFT, EI-MS data and Job's plot were applied for determining the sensing mechanism of CHB with Zn2+ and the results showed that a type of 2:1 complex was formed between CHB and Zn2+ with the binding constant was 1.32 × 104 M-2. At last, probe CHB was successfully applied for the imaging of Zn2+ in living cells.

Visible Light‐Initiated Catalyst‐Free One‐Pot, Multicomponent Construction of 5‐Substituted Indole Chromeno[2,3‐b]pyridines

AbstractA visible light‐initiated pseudo four‐component reaction of salicylaldehydes, indole and malononitrile in aqueous ethyl lactate is described. This pot, atomic and step economic (PASE) methodology provides a practical approach for the preparation of various 5‐substituted indole chromeno[2,3‐b]pyridines from readily available starting materials at ambient temperature without any catalyst. High yields and excellent functional groups tolerance are observed.magnified image