Three-component synthesis of novel spirooxindole–furan derivatives using pyridinium salts

A simple and efficient synthesis of novel spirooxindole–furan derivatives has been investigated by a modified version of the“interrupted” Feist–Bénary (IFB) reaction of isatin derivatives, 1,3-dicarbonyl compounds and N-phenacyl pyridinium salts in the presence of triethylamine. The reaction has been carried out under mild conditions in ethanol, and the products were obtained in good to moderate yields with a simple work-up procedure.     

Three-component reactions involving quinoline or isoquinoline,dialkyl acetylenedicarboxylate and β-trifluoroacetyl vinyl ethyl ether

The three-component reactions (TCRs) involving quinoline or isoquinoline, dialkyl acetylenedicarboxylate and β-trifluoroacetyl vinyl ethyl ether were investigated. The reaction proceeded smoothly under ambient temperature in DMSO to give the 4-trifluoroacetyl substituted benzo[c]quinolizine derivatives in moderate yields. However, under the same reaction condition, isoquinoline afforded the 2-trifluoromethyl substituted 1-oxa-(11H)-benzo[a]dihydroquinolizine or 4-trifluoroacetyl substituted benzo[a]dihydroquinolizine products. The possible reaction pathways were proposed.     

Three-component one-pot synthesis of 1,2,3,4-tetrahydroquinoline derivatives in hexafluoroisopropanol

The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4-tetrahydroquinline derivatives in moderate yields.     

Three-component synthesis of polysubstituted pyrroles from α-diazoketones, nitroalkenes, and amines

Polysubstituted pyrroles are regiospecifically synthesized via the copper-catalyzed three-component reaction of α-diazoketones, nitroalkenes, and amines under aerobic conditions. The cascade process involves an N-H insertion of carbene, a copper-catalyzed oxidative dehydrogenation of amine, and a [3 + 2] cycloaddition of azomethine ylide.     

Phosphomolybdic acid promoted Kabachnik–Fields reaction: an efficient one-pot synthesis of α-aminophosphonates from 2-cyclopropylpyrimidine-4-carbaldehyde

2-Cyclopropylpyrimidin-4-yl-aryl/benzothiazole derived α-aminophosphonates were synthesized in a simple and efficient method from a three-component condensation reaction of 2-cyclopropylpyrimidin-4-carbaldehyde, various anilines/benzothiazole amines, and different phosphites by using 0.5 mol % of phosphomolybdic acid (PMA, H₃PMo₁₂O₄₀) in dichloromethane at room temperature in good to excellent yields with short reaction times.     

Three-component one-pot reaction for the synthesis of β-amide ketones

β-amide ketones were synthesised by a three-component one-pot reaction of phenylacetylene, aldehydes, and amides in anhydrous acetonitrile containing trifluoroacetic acid and acetic acid in the presence of AlCl₃ catalyst. The title compound structures were identified by ¹H NMR, ¹³C NMR, MS, and elemental analysis.     

Triphenylphosphine-catalysed one-pot synthesis of γ-butyrolactone derivatives and highly substituted enones via reaction of dimethyl acetylenedicarboxylate and aryl aldehydes

The reaction between dimethyl acetylenedicarboxylate and various aryl aldehydes in the presence of triphenylphosphine leads to unsaturated γ-butyrolactone derivatives and highly substituted enones in fairly good yields at room temperature.     

3-Phenacylideneoxindoles with tosylmethyl isocyanide and MeOH through C–C bond cleavage: facile synthesis of pyrrole and 2H-pyrrolo[3,4-c]quinoline derivatives

A novel reaction of 3-phenacylideneoxindoles (1) with tosylmethyl isocyanide (2a) and MeOH through C–C bond cleavage has been developed. The reaction proceeded under mild conditions, providing a powerful synthetic tool for the construction of pyrrole derivatives (3) from easily accessible starting materials and synthesis of 2H-pyrrolo[3,4-c]quinolines (4) by further dehydration of 3.     

Nano Pt–TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol

Nanosized platinum particles loaded on the TiO₂ nanoparticles were prepared to assess its photocatalytic activity in simple one-pot synthesis of quinaldines from anilines in ethanol using UV light. The catalyst was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy, X-ray photoelectron spectra (XPS), Brunauer?CEmmer?CTeller surface area, atomic force microscope and diffuse reflectance spectra. XRD patterns revealed that the crystal structure of Pt?CTiO₂ resembled anatase phase of TiO₂. The UV?CVis spectra indicated an increase in absorption of visible light when compared to TiO₂. XPS analysis reveals that platinum particles are present mainly in metallic form. Furthermore, TEM analysis showed non-spherical-shaped Pt?CTiO₂ nanoparticles of the diameter 10?C30?nm. Upon irradiation in the presence of Pt?CTiO₂, aniline and oxidation products derived from ethanol undergo condensation?Ccyclization to afford quinaldines. Higher efficiency of Pt?CTiO₂ than Au?CTiO₂ in the conversion of aniline to quinaldines is due to the higher work function of Pt.     

A one-pot multicomponent synthesis of polysubstituted thiophenes via the reactions of an isocyanide, α-haloketones,and β-ketodithioesters in water

An efficient synthesis of polysubstituted thiophene derivatives is achieved via the multicomponent reaction of β-ketodithioesters, α-haloketones, and cyclohexylisocyanide in aqueous medium.     

Phenanthroline–dipyrromethene conjugates: synthesis,characterization, and spectroscopic investigations

Mono- and tri-topic ligands, based on dipyrromethenes and the 1,10-phenanthroline nucleus, as well as BF₂ complexes derived thereof are described. While BODIPY 12 has been X-ray crystallographically characterized, the structural features of the free ligands 9 and 10 may render them useful as precursors for the elaboration of novel supramolecular architectures.     

Rapid and efficient one-pot microwave-assisted synthesis of 2-phenylimidazo[1,2-a]pyridines and 2-phenylimidazo[1,2-a]quinoline in water–PEG-400

An effective, expeditious, environmentally benign one-pot synthesis of 2-phenylimidazo[1,2-a]pyridines and 2-phenylimidazo[1,2-a]quinoline from easily available starting materials as aromatic carbonyl compound, 2-amino pyridine, succinamide, and in situ generated α-iodo acetophenone in combination with green solvent PEG-400 and water (2:1) under microwave irradiation. The newly developed protocol with excellent yield of product in very short time of reaction by avoiding the use of lachrymatric α-chloro and α-bromocarbonyl compounds, volatile, toxic organic and hazardous solvents, reagents is the advantage of this research work. The final products were confirmed by their characterization data such as ¹H NMR, ¹³C NMR, high resolution mass spectrometry (HRMS) and were compared with its reported method.     

A convenient one-pot synthesis of 4-amino-3-arylpyrazoles from α-phthaloylaminoacetophenones

Condensation of α-phthaloylaminoacetophenones 1a-c with N,N-dimethylformamide dimethyl acetal afforded the novel enamines 3a-c. Cyclization of 3 with hydrazine, alkylhydrazine or phenylhydrazine salts (4a-d) gave 4-phthaloylamino-3-arylpyrazoles 7–9 in high yields. Deprotection of 7–9 was accomplished with hydrazine to provide 4-amino-3-arylpyrazoles 5 in good yields.     

Highly efficient one-pot synthesis of fused pyrimidones from 2-heteroaryl amines and Morita–Baylis–Hillman carbonates via intermolecular cyclocondensation

A highly selective and efficient cyclocondensation reaction for construction of various 3-substituted-2H-pyrido[1,2-a]pyrimidin-2-ones and related fused pyrimidones from allylic carbonates and 2-heteroaryl amines has been developed. The transformation involves one-pot sequential aza-Michael addition, intramolecular acyl substitution, and [1,3]-H shift. The method is catalyst free, eco-friendly, scalable, and completes within a short reaction time, with no work-up, no column purification, and demonstrate a broad functional group tolerance.     

Facile one-pot synthesis of tetrahydroisoquinolines from amino acids via hypochlorite-mediated decarboxylation and Pictet–Spengler condensation

A convenient method for oxidative decarboxylation of α-amino acids is presented. The aldehyde products may be isolated or converted to tetrahydroisoquinolines by addition of dopamine via Pictet–Spengler reaction. Racemic products are generated by phosphate buffer >300 mM to maximize regioselectivity. (S)-Enantiomer products are generated by norcoclaurine synthase reaction in maleic acid buffer to minimize chemical background reaction.     

Cellulose–silica composite aerogels from “one-pot” synthesis

Cellulose–silica composite aerogels were prepared via “one-pot” process: aqueous solutions of cellulose–8 wt% NaOH and sodium silicate were mixed, coagulated and dried with supercritical CO₂. The system was studied both in the fluid and solid (dry) states. Cellulose and sodium silicate solutions were mixed at different temperatures and concentrations; mixture properties were monitored using dynamic rheology. The gelation time of the mixture was strongly reduced as compared to that of cellulose–NaOH solutions; we interpret this phenomenon as cellulose self-aggregation inducing partial coagulation due to competition for the solvent with sodium silicate. The gelled cellulose/sodium silicate samples were placed in aqueous acid solution which completed cellulose coagulation and led to in situ formation of sub-micronic silica particles trapped in a porous cellulose matrix. After drying with supercritical CO₂, an organic–inorganic aerogel composite was formed. The densities obtained were in the range of 0.10–0.25 g/cm³ and the specific surface area was between 100 and 200 m²/g. The silica phase was shown to have a reinforcing effect on the cellulose aerogel, increasing its Young’s modulus.     

Donor–acceptor perylenediimide–ferrocene conjugates: synthesis,photophysical, and electrochemical properties

Donor–acceptor, perylenediimide–ferrocene conjugates have been synthesized by Suzuki, and Sonogashira coupling reactions. The photophysical and electrochemical properties of these conjugates are discussed. It has been shown that fluorescence as well as the electron affinity of the perylenediimide can be tuned by attaching the appropriate ferrocenyl derivatives.     

The pyridazine–tetrathiafulvalene conjugates: synthesis,photophysical, and electrochemical properties

To study the electronic interactions in donor–acceptor (D–A) conjugates as a precursor of optoelectronic materials, a series monopyridazine-annulated tetrathiafulvalenes and a bispyridazine-annulated tetrathiafluvalene were synthesized by a condensation reaction of 2,3-dimethoxycarbonyl-6,7-dibutylthiotetrathiafulvalene or/and 2,3,6,7-tetramethoxycarbonyltetrathiafulvalene with hydrazine hydrate and structurally characterized by conventional chemical and physical methods. Their electronic properties have been studied experimentally by the combination of electrochemistry and UV–vis spectroscopy. All of monopyridazine-tetrathiafulvalene conjugates 7–13 show intramolecular charge transfer interaction in ground states, which is rationalized on the basis of density functional theory. Their HOMO energy levels and E_g^opt values were estimated to be ?4.88 to ?5.07 eV from cyclic voltammetry and 2.43–2.79 eV from the absorption spectra, respectively. The X-ray crystallographic analyses of the pyridazine–tetrathiafulvalene conjugates 7, 11–13 are also reported.