A facile electrochemical synthesis of covellite nanomaterials at room temperature

A novel method for the electrochemical synthesis of covellite (CuS) nanoparticles (NPs) in aqueous phase was developed. In this experiment, thioglycerol (TG) is used as the catalyst for the hydrolysis of sodium thiosulfate, the sulfur source for the synthesis of CuS. Cu foil, which acts as the sacrificing anode, is oxidized to Cu²⁺ by applying a potential of 0.5 V while OH^- was produced on the cathode surface at the same time. The production of OH^- facilitates the reaction between Cu²⁺ and thiosulfate under the catalysis of TG. The evolution of hydrogen bubbles effectively prevents the deposition of copper sulfide on the cathode. Copper sulfide sols of “golden-brown”, and “dark-green” forms can be obtained by varying the concentration of TG. The “golden-brown” copper sulfide sols are also observed to convert to the green form with time, and the rate of this conversion process is faster at higher temperatures. X-ray diffraction (XRD) and chemical analysis indicate that the “dark-green” form of product is pure hexagonal phase CuS. The obtained CuS NPs were covered by a layer of TG as suggested by Fourier transform infrared (FTIR) data. The size and morphology of the particles are studied by transmission electron microscope (TEM).     

Preparation of 8-substituted xanthine CVT-124 precursor by late stage pyrimidine ring closure.

To develop a novel route for the scaleable synthesis of the chiral xanthine CVT-124 (1, aka. BG9719), a method for the late stage pyrimidine ring closure of the nitrogen-protected endo 2-norbornenyl imidazole 3 was developed. The three-component coupling of benzylamine, 2-cyanoglycine ethyl ester (4), and methyl 5-norbornene-2-carboximidate hydrochloride (5) was demonstrated to achieve 3 in 23-46% isolated yields. The imidazole 3 was then elaborated to construct the N-benzyl xanthine 2 as a 1:1 mixture of exo and endo isomers, which were separable at this stage by chromatography. The nitrogen-protected endo xanthine 2 is a key intermediate in the synthesis of CVT-124.     

A facile and rapid synthesis of N-benzyl-2-substituted piperazines

A facile and rapid synthetic approach of N-benzyl-2-substituted piperazine building-blocks via an Ugi strategy is described. This strategy is high yielding (80-92% overall yield), step-efficient and fast using microwave heating and tert-butylisocyanide as a convertible isocyanide. This method is useful for the obtention of key intermediates in medicinal chemistry.     

A facile synthesis of 3-substituted indoles

1-Benzoyl-3-bromomethylindole (2a) or 1-benzenesulfonyl-3-bromomethylindole (2b) reacts with C, N, O, and P-containing nucleophiles to give potential intermediates for the synthesis of a wide range of indole alkaloids and pharmacologically important substances, in good to excellent yields.     

A facile synthesis of bisquinoline derivatives via the Williamson reaction

A series of new bisquinoline systems, ethyl 2-((quinolin-8-yloxy)methyl)quinoline-3-carboxylate derivatives (3a–i), were synthesized by Williamson reaction of ethyl 2-(halogenmethyl)quinoline-3-carboxylates (4a–c) with 8-hydroxyquinolines (5a–c) in CH₃CN as solvent and in the presence of K₂CO₃ as base. Characterization of these bisquinoline compounds was primarily achieved by use of spectral data and X-ray crystallography. This procedure enables easy access to bisquinoline compounds in a short reaction time and the products are obtained in high yields.     

A mild and facile method for one pot synthesis of 2,5-di-substituted 1,3,4-oxadiazoles at room temperature

2,5-Di-substituted 1,3,4-oxadiazoles 3a-n have been synthesized as a one pot procedure from the reaction of acid hydrazide 1, acyl halides 2 and phosphorus pentoxide in acetonitrile at room temperature. High yield, short reaction time （10-15 min）, mild condition, and easy work-up are advantages of this methodology.     

A facile synthesis of 1,4-benzodiazepine derivatives via Ugi four-component condensation

A simple two-step route to 4,5-dihydro-3H-benzo[1,4]diazepin-5-ones is described. This synthesis, based on the isocyanide chemistry, allows a wide variety of substitution patterns starting from commercially available or easily obtainable reagents.     

Citric acid:An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature

The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol,and most of the reactions were completed in less than 1 min.     

Efficient synthesis of fluorinated biphenyl derivatives via Pd-catalyzed Suzuki coupling reactions in aqueous solvents at room temperature

A variety of fluorinated biphenyl derivatives were obtained in good yields in aqueous solvents at room temperature by Suzuki coupling reaction of aryl bromides and aryl boronic acid in the presence of high activity catalyst—some air-stable hemilabile PO coordinated cyclopalladated complexes. The structures of above catalysts were characterized by element analyses, IR, ¹H NMR, ¹³C NMR and ³¹P NMR.     

Greener approach towards the facile synthesis of 1,4-dihydropyrano[2,3-c]pyrazol-5-yl cyanide derivatives at room temperature

This report describes triethylammonium acetate (TEAA) ionic liquid catalyzed one pot synthesis of 6-amino-4-aryl-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles by the reaction of aromatic aldehyde, malononitrile and 3-methyl-1-phenyl-2-pyrazolin-5-one at room temperature. TEAA plays dual role as reaction media and catalyst. It can also be easily recovered and reused in several runs. TEAA provides greener reaction protocol to present methodology which obviates the need of organic solvents, expensive and toxic catalyst.     

A diastereoselective construction of pyrazinoisoquinoline skeletons via tandem cyclization of phenylalanine derivatives: a facile synthesis of optically active pyrazinoisoquinolines

A facile and stereocontrolled construction of optically active pyrazinoisoquinoline skeletons based on tandem cyclization of enantiopure phenylalanine derivatives was examined. The reaction provided optically active 6,11b-trans pyrazinoisoquinoline ring systems in excellent diastereoselectivity, and this method was applicable to the cyclization of phenylalanine derivatives with diverse substituents.     

Total synthesis of ascididemin via anionic cascade ring closure

A new and convergent synthesis of ascididemin is presented. Using an anionic cascade ring closure as the key step, this natural product is obtained in 45% overall yield in just 6 steps starting from 2'-fluoroacetophenone. This new approach was extended to the synthesis of a new isomer of ascididemin.     

A facile one-step synthesis of chromeno[4,3-b]pyridine derivatives promoted by niobium pentachloride

Chromenes are part of an important class of heterocyclic compounds, natural or synthetic, and have many biological and chemical applications. Among them, chromenopyridines has arisen as a promising material for pharmacological applications. In this work is described a simple and cost-effective method to synthesize chromeno[4,3-b]pyridine derivatives from multicomponent reaction between 4-aminocoumarin, benzaldehyde derivatives, and ethyl benzoylacetates catalyzed by niobium pentachloride. The new method provides good yields with reasonable reaction times, under mild reaction conditions.     

Iron-catalyzed selective oxidation of 5-hydroxylmethylfurfural in air: A facile synthesis of 2,5-diformylfuran at room temperature

An iron(Ⅲ)-catalyzed selective oxidation of 5-HMF to 2,5-DFF in air at room temperature was developed.This approach gives 2,5-DFF with good selectivity and yields. Additionally, a two-step process was developed for the oxidation of 2,5-DFF to 2,5-FDCA at remarkably high substrate concentrations. This work demonstrates unequivocally the great potential of iron as a cheap and earth-abundant catalyst for the development of new protocols for the conversion of biomass to value-added chemicals.     

A facile synthesis of 5-substituted 1-methyluracils and cytosine

A facile, general synthesis for a number of 5-substituted-1-methyluracils and cytosine which is suitable for the preparation of micro-quantities is reported. In contrast to other methods, the 5-substituent plays no role in determining the position of alkylation. 1-Methyl-5-hydroxymethyluracil and 1-methyl-5-formyluracil have also been synthesized by an alternate route.     

CsF promoted rapid synthesis of spirooxindole-pyran annulated heterocycles at room temperature in ethanol

A newer, versatile, and straightforward synthetic strategy for the construction of functionalized spirooxindole-pyran annulated heterocycles is described. The procedure is based on CsF-promoted rapid tandem Knoevenagel-Michael-Cyclocondensation reaction of isatin, malononitrile, and 4-hydroxycoumarin/barbituric acids/pyrazolone at room temperature in ethanol. This methodology has various advantages like easy operational, excellent yields within short reaction time (3-25 min), and simple isolation of products. The CsF has a dual role as a base and carbonyl activator.     

A convenient one-step synthesis of fluoroethylidene derivatives

A convenient one-step synthesis of gem-monofluoroalkylolefins starting from aldehydes or ketones was developed. This method comprises the utilisation of 2-(1-fluoroethyl)sulfonyl-1,3-benzothiazole according to Julia's procedure and opens a new opportunity for the synthesis of fluoroalkylidene derivatives.     

Greener approach towards the facile synthesis of 1,4-dihydropyrano[2,3-c]pyrazol-5-y1 cyanide derivatives at room temperature

<正>This report describes triethylammonium acetate(TEAA) ionic liquid catalyzed one pot synthesis of 6-amino-4-aryl-5-cyano-3- methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles by the reaction of aromatic aldehyde,malononitrile and 3-methyl-1-phenyl-2- pyrazolin-5-one at room temperature.TEAA plays dual role as reaction media and catalyst.It can also be easily recovered and reused in several runs.TEAA provides greener reaction protocol to present methodology which obviates the need of organic solvents,expensive and toxic catalyst.