以淀粉溶液为催化剂锅三组分法合成四氢苯并[b]吡喃和3,4-二氢吡喃并[c]苯并吡喃衍生物简

Tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives were synthesized via a one-pot three-component condensation of aromatic aldehydes with malononitrile and dimedone or 4-hydroxycoumarin in excellent yields in the presence of starch solution as a highly efficient homogenous catalyst. The use of a nontoxic and biodegradable catalyst, simple work-up procedure, and short reaction time are advantages of this method.     

An environmentally friendly synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives catalyzed by tungstate sulfuric acid

An efficient three-component synthesis of 6-amino-4-aryl-5-cyano-3-metriyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles via a reaction between 3-methyl-1-phenyl-2-pyrazolin-5-one,aromatic aldehydes and malononitrile using tungstate sulfuric acid as a catalyst was described.Mild conditions,good to excellent yields,easily available catalyst and easy work-up are the key features of this method.     

Silica-coated magnetic NiFe2O4 nanoparticles-supported H3PW12O40; synthesis,preparation, and application as an efficient,magnetic, green catalyst for one-pot synthesis of tetrahydrobenzo[b]pyran and pyrano[2,3-c]pyrazole derivatives

Research on Chemical Intermediates - A powerful, magnetic, supported, acid catalyst, NiFe2O4@SiO2–H3PW12O40, was prepared by chemical support of Keggin (H3PW12O40) heteropolyacid (HPA) on...     

Magnesium ferrichromate nanoparticles: an efficient and recyclable catalyst in the synthesis of pyrano[2,3-c]pyrazole derivatives

Research on Chemical Intermediates - Magnetically separable magnesium ferrichromate nanoparticles (MgFeCrO4 NPs) were synthesized by aqueous combustion synthesis (ACS) using glycine as the fuel....     

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.     

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.     

Electrogenerated base-promoted synthesis of tetrahydrobenzo[b]pyran derivatives

An efficient and convenient synthesis of tetrahydrobenzo[b]pyrans is described, using an electrogenerated base of the anion of malononitrile in a one-pot, three component condensation of an aromatic aldehyde, an active methylene compound and dimedone. The reaction is carried out at room temperature in acetonitrile with the use of a sacrificial magnesium anode in a single-compartment cell.     

[DBU][Ac]-catalyzed mild preparation of 6-amino-4-aryl-5-cyano-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole derivatives

We report a new, one-pot, efficient, four-component condensation of hydrazine hydrate, ethyl acetoacetate, arylaldehydes, and malononitrile in the presence of a reusable weakly basic ionic liquid, 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate, as catalyst, for synthesis of 6-amino-4-aryl-5-cyano-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole derivatives under solvent-free conditions at room temperature. The method has several advantages, for example good yields, short reaction times, and simple work-up procedure.     

Molecular sieves: an efficient and reusable catalyst for multi-component synthesis of dihydropyrano[2,3-C]pyrazole derivatives

An efficient synthesis of dihydropyrano[2,3-C]pyrazole derivatives catalyzed by molecular sieves in ethanol under reflux and ultrasound irradiation has been described. The efficiency of catalyst has been compared with other aluminates and silicate based catalyst in order to optimize catalyst for the said organic transformation. This protocol is very useful due to easy recovery of the catalyst and its reusability, short reaction time, excellent yields, and avoidance of environmentally hazardous solvents.     

Electrochemically induced one pot synthesis of 1,4-dihydropyrano[2,3-c]-pyrazole-5-carbonitrile derivatives via a four component-tandem strategy

An efficient one pot, multicomponent-tandem synthesis of highly functionalized 1,4-dihydropyrano[2,3-c]-pyrazole-5-carbonitrile is reported by electrochemically induced condensation of ethyl acetoacetate, hydrazine hydrate, malononitrile and various aromatic aldehydes. The reaction is carried out in an undivided cell, at a constant current in the presence of NaBr as a supporting electrolyte and ethanol as solvent.     

Phenylboronic acid as an efficient and convenient catalyst for a three-component synthesis of tetrahydrobenzo[b]pyrans

Phenylboronic acid, a non-toxic compound, is used as catalyst for an efficient, rapid, and one-pot three-component synthesis of tetrahydrobenzo[b]pyrans in good to excellent yields. This new procedure has the advantages of operational simplicity, shorter reaction time, higher yields and minimum pollution of the environment.     

活性炭负载硫化锡纳米颗粒作为高效可重复使用Lewis酸催化剂催化三组分一锅法合成4H-吡喃[2,3-c]吡唑衍生物(英文)

Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transmission electron microscopy(TEM), X-ray diffraction, reflective ultravio-let-visible spectrophotometry, and spectrofluorimetry. Calculations based on the SEM and TEM images showed that the sizes of the SnS -NPs immobilized on the AC were 30–70 nm. The prepared nanocomposite was used as a heterogeneous Lewis acid catalyst for the three-components one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol at 80 ℃. The reactions were efficiently performed in the presence of the prepared catalyst in short reaction times, and gave the desired products in high yields. This catalyst can be easily recovered by simple filtration and recycled up to eight consecutive times without significant loss of its efficiency.     

Tin sulfide nanoparticles supported on activated carbon as an efficient and reusable Lewis acid catalyst for three-component one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives

Tin sulfide nanoparticles (SnS‐NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon (AC) and were investigated using field‐emission scanning electron mi‐croscop...     

Sodium ascorbate as an expedient catalyst for green synthesis of polysubstituted 5-aminopyrazole-4-carbonitriles and 6-amino-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles

Research on Chemical Intermediates - Sodium ascorbate (SA) was used as a safe catalyst for the synthesis of 5-aminopyrazole-4-carbonitriles from the one-pot three-component cyclocondensation (3-CC)...     

New approach for the synthesis of 3H-pyrrolo[2,3-c]isoquinoline derivatives

Synthesis of new 2,3-diaryl-3H-pyrrolo[2,3-c]isoquinoline derivatives has been elaborated starting from isoquinoline-3-amine. Buchwald–Hartwig arylation and subsequent iodination in position 4 afforded 3-arylamino-4-iodoisoquinolines. These compounds were subjected to Sonogashira cross-coupling reactions with some selected acetylenes, and the resulting coupled products underwent cyclization in the presence of tetrabutylammonium fluoride to give title derivatives.