A simple and one-pot synthesis of 2,3,4,5-tetrasubstituted 4,5-dihydro-3H-1,4-benzodiazepines

2,3,4,5-Tetrasubstituted 4,5-dihydro-3H-1,4-benzodiazepines were synthesized in one-pot by a new sequential Ugi 4CC/Staudinger/aza-Wittig reaction, starting from easily accessible o-azidobenzaldehyde, α-amino ketone hydrochloride, isocyanide and carboxylic acid.     

A simple and efficient method for the synthesis of highly substituted imidazoles using 3-aroylquinoxalin-2(1H)-ones

3-Aroylquinoxalin-2(1H)-ones were found to be hetero analogues of α-diketones for the efficient, one-pot, three component synthesis of 2,4,5-trisubstituted imidazoles and imidazo[1,5-a]quinoxalin-4(5H)-ones in boiling methanol. The key advantages of this process are high yields, ready availability and low cost of 3-aroylquinoxalin-2(1H)-ones and easy work-up and separation of the products by non-chromatographic methods. Furthermore, the presence of an ortho-iminoanilide fragment at position 4 of the imidazoles obtained has made it possible to produce 2-(imidazol-4-yl)benzimidazoles in almost quantitative yields.     

A one-pot synthesis of isoindolin-1-imine derivatives

A one-pot procedure was developed for the synthesis of isoindolin-1-imine derivatives by a simple three-component condensation of 2-cyanobenzaldhyde, ammonium acetate, and 4-hyroxycoumarin derivatives or 1,3-dicarbonyl compounds or 4-hydroxyquinolin-2(1H)-one in ethanol under reflux for 20–60 min with excellent yields. The advantages of this procedure are operational simplicity, excellent yields, and short reactive time, without catalyst, easy workup, and green environmental impact.     

Efficient synthesis of arylaminotetrazoles in water

Arylaminotetrazole derivatives are synthesized efficiently by the reaction of arylcyanamides and sodium azide in the presence of ZnCl₂ under aqueous conditions at reflux. Generally, isomer of 5-arylamino-1H-tetrazole can be obtained from arylcyanamides carrying electron-withdrawing substituent on aryl ring and as the electropositivity of substituent is increased, the product is shifted toward the isomer of 1-aryl-5-amino-1H-tetrazole.     

Simple and efficient one-pot synthesis of N-phenyl-3,5-difunctionalized pyrazoles

A facile one-pot synthesis of N-phenyl-3,5-difunctionalized pyrazoles is described. The dialkyl 2-[(Z)-phenylhydrazono]succinate intermediate, which is prepared in situ from the mixture of phenylhydrazine and dialkyl acetylenedicarboxylate reacts with aroyl chloride or fumaryl chloride to afford the title compounds. Different types of compounds containing COCl functional group were used to investigate the scope and limitation of the reaction. Two -CO₂R and -O₂C groups at 3- and 5-position are potentially capable to convert to other functional groups. The reaction conditions are relatively mild and the yields are good.     

A novel synthesis of new 2-aryl-6-(arylamino)-1H-imidazo[1,2-b]pyrazole-7-carbonitrile derivatives

New 2-aryl-6-(arylamino)-1H-imidazo[1,2-b]pyrazole-7-carbonitriles are synthesized in good yields, via cyclocondensation of 5-amino-1-(2-oxo-2-arylethyl)-3-(arylamino)-1H-pyrazole-4-carbonitriles, which are prepared by the reaction of 5-amino-3-arylamino-1H-pyrazole-4-carbonitriles and α-bromoacetophenone derivatives in the presence of K₂CO₃ using acetone as the solvent.     

A new and efficient one-pot synthesis of 2-hydroxy-1,4-dihydrobenzoxazines via a three-component Petasis reaction

The secondary amines synthesized by the reaction between 2-aminophenols and aromatic aldehydes, via the reduction of the corresponding imines, were employed in the synthesis of new 2-hydroxy-2H-1,4-benzoxazine derivatives through a one-pot Petasis multicomponent reaction in good to excellent yields.     

A simple and efficient synthesis of gem-dihydroperoxides from ketones using aqueous hydrogen peroxide and catalytic ceric ammonium nitrate

Ketones were efficiently converted into the corresponding gem-dihydroperoxides in high yields within a short period of time on treatment with aqueous H₂O₂ (50%) in the presence of a catalytic amount of CAN in acetonitrile at room temperature.     

Iron fluoride: the most efficient catalyst for one-pot synthesis of 4H-pyrimido[2,1-b]benzothiazoles under solvent-free conditions

A new iron fluoride assisted convenient and efficient strategy for the preparation of 4H-pyrimido[2,1-b]benzothiazoles derivatives in solvent-free media is described. The reactions can be performed at low-catalyst loadings with excellent functional group tolerance. The catalyst can be readily recovered and reused for next reaction for at least three runs without any significant impact on the yields of the products. The easy recovery of the catalyst and high yield of the products make the protocol attractive, sustainable, and economic.     

A convenient and mild synthesis of new 2-aryl-3-hydroxy-6,7-dihydro-1H-indol-4(5H)-ones via a one-pot,three-component reaction in water

A simple and convenient synthesis of 2-aryl-3-hydroxy-6,7-dihydro-1H-indol-4(5H)-ones is achieved in high yields via the one-pot, three-component reaction of arylglyoxals, 1,3-cyclohexanedione, and ammonium acetate in water under reflux conditions.     

A simple and highly efficient synthesis of N-phenyl-2-polyfluoroalkyl-4-quinolones from 2-anilinoacetophenone and RFCO2Et

The condensation of 2-anilinoacetophenone with R_FCO₂Et (R_F = CF₂H, CF₃, C₂F₅) in the presence of LiH in THF affords the corresponding N-phenyl-2-polyfluoroalkyl-4-quinolones in excellent yields.     

A facile and convenient approach to the synthesis of 3,5-diaryl-1<Emphasis Type="Italic">H</Emphasis>-pyrazoles

A simple and convenient one-pot synthesis route is described for the synthesis of 3,5-diaryl-1H-pyrazoles in short reaction times from the reaction of α-epoxyketones with semicarbazide hydrochloride under mild conditions. Correspondence: Farzad Nikpour, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416, Sanandaj, Iran.     

A mild and efficient one-pot synthesis of 2-dihydroimidazoles from aldehydes

The reactions of various aldehydes and 1,2-diamines followed by NXS treatment proceed at 0 °C-rt to give the corresponding dihydroimidazoles in high yields. The reaction is mild, and many functional groups such as halogens, nitriles, and esters can exist.     

Diketene as an alternative substrate for a new Biginelli-like multicomponent reaction: one-pot synthesis of 5-carboxamide substituted 3,4-dihydropyrimidine-2(1H)ones

5-Carboxamide substituted 3,4-dihydropyrimidine-2(1H)one derivatives were synthesized in a simple and efficient method from the one-pot four-component reactions of an aliphatic or aromatic amine, diketene, an aromatic aldehyde and urea or thiourea in the presence of p-toluenesulfonic acid as a catalyst under mild reaction conditions at ambient temperature.     

New chemistry of diazafulvenium methides: one way to pyrazoles

Diazafulvenium methides generated from the solution pyrolysis of pyrazolo[1,5-c][1,3]thiazole-2,2-dioxides participate in [8π+2π] cycloadditions giving pyrazolo[1,5-a]pyridine derivatives. 1-Methyl-diazafulvenium, generated under flash vacuum pyrolysis reaction conditions, undergoes an intramolecular sigmatropic [1,8]H shift giving 1-vinyl-1H-pyrazoles.     

CuO nanoparticles catalyzed simple and efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones and quinazolin-4(3H)-ones under ultrasound irradiation in aqueous ethanol under ultrasound irradiation in aqueous ethanol

A CuO nanoparticle-catalyzed one-pot process has engineered for the preparation of diverse quinazolinones from the readily available isatoic anhydride, aldehydes and amine or ammonium. For amine substrates the reactions afford 2,3-dihydroquinazolin-4(1H)-ones in aqueous ethanol promoted by ultrasound irradiation. However, the ammonium substrates undergo intramolecular electron transfer and rearrangement yielding quinazolin-4(3H)-ones. The catalyst is recyclable four times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance (46 quinazolinones are synthesized and 9 of them are reported firstly), and providing moderate to excellent yield of the products under mild conditions.     

A novel one-pot, three-component reaction for the synthesis of isocoumarin-condensed pyrazoles

The one-pot, three-component reaction of substituted homophthalic anhydrides with hydrazine in DMF as solvent and reactant, at reflux temperature, afforded isochromeno[3,4-c]pyrazole-5(2H)-one derivatives in high yields. The mechanism and roles of the substrates were investigated and it was found that cyclic hydrazides were formed as intermediates.     

A simple and efficient method for synthesis of fluorine-containing saccharide esters and antiviral activity

Sixteen new fluorine-containing saccharide esters from fluorine-containing benzoic acids and α-O-acetylglycosyl bromide were synthesized in the presence of 4-dimethylaminopyridine (DMAP) and triethylamine (Et₃N) under mild conditions in good yields and their structures were clearly verified by IR, ¹H NMR, MS and elemental analysis. This method has high stereospecificity, the configuration is unitary, the new synthesized compounds are all of β-configuration. The results of bioassay showed that these title compounds possess potential antiviral activities against tobacco mosaic virus (TMV).     

An efficient bakers’ yeast catalyzed synthesis of 3,4-dihydropyrimidin-2-(1H)-ones

Bakers’ yeast (Saccharomyces cerevisiae) efficiently catalyzes the three-component Biginelli reaction of aldehydes, β-keto esters, and urea/thiourea to form 3,4-dihydropyrimidin-2-(1H)-ones in good to excellent yields.