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Aromatic aldehydes

Tìm thấy 20+ kết quả cho từ khóa "Aromatic aldehydes"

Application of guanidine and its salts in multicomponent reactions

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and coworkers by the reaction of aromatic aldehydes 4, malonitrile 27, and guanidinium carbonate 6.

Progress in the chemistry of 3-amino-9-ethylcarbazole

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Shi et al. have reported the synthesis of novel functionalized 1-aryl-8-ethyl-5,8-dihydro-1H-[1,4]thiazepino[5,6- c ]-carbazol-4(3 H) -ones (142) by the microwave- assisted reaction of compound 12 with aromatic aldehydes 127 and 2-mercaptoacetic acid 89 under solvent-free conditions (Scheme 51). Formation of diindolo[3,2-a:3',2'-h]phenazine.

Green and efficient synthesis of novel bispyrazoles through a tandem Knoevenagel and Michael type reaction using nanowire zinc oxide as a powerful and recyclable catalyst

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Afterwards, the feasibility of the reaction was further studied with various aromatic aldehydes under optimized conditions, which successfully led to products with high yields in short reaction times. The effect of catalyst amount on synthesis of compound 3a. Synthesis of bispyrazoles 3 using ZnO NWs (2 mol%)..

One-pot multicomponent synthesis of piperidinium 3,3’-(arylmethylene) bis (2-hydroxynaphthalene-1,4-diones): NMR spectroscopic and X-ray structure characterization

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In conclusion, with the aim of achieving important organic synthesis, we have developed a one-pot, pseudo- four-component synthesis of new piperidinium 3,3’-(arylmethylene)bis(2-hydroxynaphthalene-1,4-dione) salts from the reaction between 2-hydroxy-1,4-naphthoquinone, piperidine, and aromatic aldehydes. The formation of salts was characterized by FT-IR, 1 H NMR, and 13 C NMR analysis.

Turkish perlite supported nickel oxide as the heterogeneous acid catalyst for a series of Claisen–Schmidt condensation reactions

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Proposed mechanism of condensation of cyclohexanone and aromatic aldehydes over NPC‒15..

A rapid, efficient, and green synthesis of benzo[a]chromeno[2,3-c]phenazine derivatives via microwave assistance and DABCO catalyzed a novel domino cyclization

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Using these optimized conditions, we turned our attention to investigating the scope and general appli- cability of this methodology by carrying out the synthesis of benzo[ a]chromeno[2,3- c ]phenazines using different aromatic aldehydes and various naphthols. Domino one-pot four-component synthesis of benzo[a ]chromeno[2,3- c]phenazine derivatives a.

Synthesis, characterization, and application of monodisperse poly L-Dopa microspheres

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Then 1.0 mmol 1,3-dicarbonyl compounds, 1.0 mmol aromatic aldehydes, and 0.032 g of PDopa as the catalyst were added and refluxed for 4–6 h. After the reaction was completed the mixture was cooled down to room temperature and the catalyst was removed by simple filtration, cleaned by several washings with acetonitrile solvent, and dried for subsequent uses.

L-proline/cholesterol and diosgenin based thiourea cooperative system for the direct asymmetric aldol reaction in the presence of water

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Under the optimum reaction conditions, the reaction of electron-deficient aromatic aldehydes with cyclohexanone gave anticonfigured aldol products in moderate to high ee values (up to 93% ee) in the presence of water. The successful results for catalytic efficiency of L-proline indicate the importance of the hydrophobic.

A microwave-assisted highly stereoselective one-pot Wittig reaction under solvent-free conditions

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However, when the reaction was carried out with the aldehydes containing the electron-donating group or neutral aromatic aldehyde, comparatively less time was required for a complete conversion to olefin (Table 2, entries 1–3). It was also observed that the selectivity of the product was high in the case of parasubstituted aromatic aldehydes (Table 2, entries 2, 4, 6, and 9), while it was less with ortho- and metasubstituents (Table 2, entries 3, 5, 7, and 10)..

Recent synthetic methodologies for pyrimidine and its derivatives

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In the following year, Sheibani and colleagues condensed aromatic aldehydes 21, malononitrile 18, and amidines 22 to achieve 2- amino-5-pyrimidinecarbonitriles yield) (Scheme 3). A annulation process was employed for the synthesis of pyrimidine derivatives 27 by the condensation of aminoalkenes 24, orthoester 25, and ammonium acetate 26 in the presence of Lewis acid catalyst in the laboratories of Sasada and coworkers (Scheme 4).

Proline-based organocatalyst-mediated asymmetric aldol reaction of acetone with substituted aromatic aldehydes: An experimental and theoretical study

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A proposed transition state structure of aldol reaction of acetone with benzaldehyde. is quite comparable for the aldol reaction of cyclohexanone with aldehydes by the same catalyst (1) [32]. It is believed that the hydrogen bonding involving the proline acid group and the aldehyde is important for the high enantioselectivity [49,50]..

Green synthesis of 2-amino-7-hydroxy-4-aryl-4H-chromene-3-carbonitriles using ZnO nanoparticles prepared with mulberry leaf extract and ZnCl2

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Abstract: A highly efficient and environmentally benign protocol for the synthesis of 2-amino-7-hydroxy-4-aryl-4H - chromene-3-carbonitrile derivatives in good to high yields (77%–97%) by one-pot three-component coupling reaction of aromatic aldehydes, malononitrile, and resorcinol under reflux condition was developed in aqueous media using ZnO nanoparticles that were prepared in the presence of mulberry leaf extract under mild conditions..

Synthesis of E-stilbene azomethines as potent antimicrobial and antioxidant agents

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The synthesis of E -stilbenes 5a–5h is described in the Scheme. 37,38 The ester functionality of compound 3 was converted to E -stilbene hydrazide (4) by treatment with hydrazine hydrate (Scheme) in the presence of ethanol as a solvent. 39 The stilbene azomethines (5a–5h) were synthesized by condensation of E -stilbene hydrazide (4) with a variety of aromatic aldehydes (Scheme).

Advances in the chemistry of pyrazolopyrazoles

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Me Ph NH 2 NH 2 . 4-Arylidene-methyl-5-oxo-4,5-dihydropyrazoles 183 were prepared via the reaction of 3-methyl-5-oxo-4,5- dihydropyrazole 182 with aromatic aldehydes. Subsequently, compounds 183 were condensed with hydrazine to give 5-[(3’-ethyl-5’-acetyl-4’-substituted pyrazolo[3,4-c ]pyrazoles 184. 1,3-Diphenyl-2-pyrazolin-5-one 185 was condensed with p-methoxybenzaldehyde to give pyrazolinones 186.

Comparative study of microwave-assisted and conventional synthesis of ibuprofen-based acyl hydrazone derivatives

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Therefore, they claimed that N- acylhydrazones derived from aromatic aldehydes in solution are in the E form. Based on the literature data, the double signals in the NMR spectra of acylhydrazones 4a–p can be attributed to the existence of amide conformers only. The signals belonging to the methylidene proton of one form was exhibited at δ 8.13–8.59 ppm, whereas the methylidene proton of the other form appeared at δ 7.86–8.31 ppm as a singlet.

Tetrahydropyridine: A promising heterocycle for pharmacologically active molecules

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Ethyl 1-(2-chloroacetyl)-4-hydroxy-2,6-diphenyl-1,2,5,6-tetrahydropyridine-3-carboxylate and their 4-O-aryl sul- fonates (Figure 1, compounds 1–6) were synthesized by Aridoss et al. 32 Raju et al. 33 Another multicomponent reaction of aromatic aldehydes, arylamines, and β -ketoester in the presence of bismuth nitrate was carried out by Yankin et al. 34 Srivastava et al.

Umpolung strategy: advances in catalytic C-C bond formations

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Benzoin condensation has a very limited substrate scope since the aromatic aldehydes with strong electron-donating or electron-withdrawing groups do not furnish the resultant product with consistent yields. Furthermore, cyanide ion does not catalyze the benzoin condensation between aliphatic aldehydes, because they tend to undergo aldol condensation. Benzoin condensations under classical reaction conditions are also limited to the synthesis of symmetrical homobenzoins..

One-pot synthesis of substituted 4H -chromenes by nickel ferrite nanoparticles as an efficient and magnetically reusable catalyst

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After obtaining favorable results from the optimization of temperature, solvent, and catalyst amount, various aromatic aldehydes carrying electron-withdrawing and electron-donating groups on the aromatic ring in the ortho, meta, and para positions and heterocyclic, aliphatic, and unsaturated aldehydes were investigated.. The effect of catalyst amount on the synthesis of substituted 4 H -chromenes.. The proposed mechanism for the synthesis of substituted 4H -chromenes is shown in Scheme 2.

A new series of Cu(II) and Ni(II) complexes of NO bidentate 4-NO2 -benzoylhydrazones: synthesis, characterization, and biological studies

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Abstract: A series of new nickel(II) and copper(II) hydrazone complexes 1–14, containing a bidentate NO-donor hydrazone ligand, derived from 4-nitrobenzoylhydrazide and several aliphatic and aromatic aldehydes were synthesized,. The spectral data of the newly synthesized complexes show the formation of a 1:2 [metal:ligand] ratio.

A Challenging Classic Coupling: Esterification of Camphoric Acid - a Steric-Hindered Polar Carboxylic Acid and Solanesol - a Long-Chain Nonpolar Alcohol

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The in situ anhydride formation offers a direct synthetic route to the hybrid compound solanesyl camphorate.. (2001), “Synthesis of new chiral Schiff bases and their application in the asymmetric trimethylsilylcyanation of aromatic aldehydes”, Tetrahedron: Asymmetry 12, pp.. [7] Up to now, there has been no report on a synthesis of monosolanesyl camphorate yet..