TiCl3 catalyzed one-pot protocol for the conversion of aldehydes into 5-substituted 1H-tetrazole

An efficient protocol has been explored for the one-pot synthesis of tetrazole derivatives with wide functional group compatibility in moderate to very high yields starting from aliphatic and aromatic substituted aldehydes. The reaction proceeds via non-isolated oxime and nitrile intermediates. The structures of the products were confirmed by IR and NMR spectroscopy. A plausible reaction mechanism is also provided.     

ZSM-5 catalyzed one pot three-component synthesis of 5-substituted-1H-tetrazoles from aldehyde

Abstract

In this paper, we report one-pot three-component synthesis of 5-substituted-1H-tetrazoles from aldehyde using zeolite-based heterogeneous catalyst (ZSM-5). Wide functional group tolerance with high chemical yield has been achieved. Moreover, heterogeneous catalyst (ZSM-5) was recovered and reused several times without significant loss of its catalytic activity     

A novel method for the synthesis of 5-substituted 1H-tetrazole from oxime and sodium azide

A simple and efficient protocol is developed for the synthesis of 5-substituted 1H-tetrazoles from various oximes and sodium azide (NaN₃) by using copper acetate as a catalyst.     

One pot solid phase synthesis of 2-substituted 2,3-dihydropyridin-4(1H)-ones on Rinkamide-resin

A novel solid phase synthesis of 2-substituted 2,3-dihydropyridin-4(1H)-ones using Rinkamide-polystyrene-resin is described. The key step involves a hetero-Diels-Alder reaction of Danishefsky's diene with solid phase bound imines, which was carefully optimized. Using this method even ketones are transformed into 2,2-disubstituted dihydropyridones.     

One pot,three-component synthesis of novel 3,4-dihydrophthalazin-2(1H)-yl-4-phenyl-4H-pyrans

Green and efficient one pot, three-component synthesis of novel 2-amino-6-(1,4-dioxo-3,4-dihydrophthalazin)-2(1H)-yl-4-phenyl-4H-pyran-3,5-dicarbonitriles 6 has been developed by condensing 3-(1,4-dioxo-3,4-dihydrophthalazin-(1H)-yl)-3-oxopropanenitrile 3, benzaldehydes 4 and active methylene compounds 5 using l-proline as catalyst in EtOH at RT.     

Copper-doped silica cuprous sulfate: A highly efficient heterogeneous nano-catalyst for one-pot three-component synthesis of 1-H-2-substituted benzimidazoles from 2-bromoanilines,aldehydes, and [bmim]N3

A facile and highly efficient one-pot three-component synthesis of 1-H-2-substituted benzimidazole derivatives from readily available substrates catalyzed by copper-doped silica cuprous sulfate (CDSCS) is described. In this method, treatment of diverse 2-bromoanilines, aldehydes, and [bmim]N₃ in DMF at 110 °C in the presence of CDSCS as a highly efficient heterogeneous nano-catalyst affords the corresponding 1-H-2-substituted benzimidazoles in good to excellent yields. The CDSCS is an inexpensive and stable nano-catalyst that could be simply prepared, recovered and reused for many consecutive reaction runs without significant loss of its activity.     

Indium(III)chloride catalyzed synthesis of novel 1H-pyrazolo[1,2-b]phthalazine-5,10-diones and 1H-pyrazolo[1,2-a]pyridazine-5,8-diones under solvent-free condition

An efficient, inexpensive and environmentally friendly synthesis of novel 3-amino-2-benzoyl-1-aryl-1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 3-amino-2-benzoyl-1-aryl-1H-pyrazolo[1,2-a]pyridazine-5,8-dione derivatives has been developed via one-pot three-component reaction of phthalhydrazide or maleic hydrazide, aldehydes and arylacetonitrile in the presence of catalytic amount of InCl₃ as a Lewis acid catalyst under solvent-free conditions. The most important features of the present protocol are mild reaction conditions, short reaction times, high yields, and a wide range of functional group tolerance.     

Iodine-promoted three-component reaction for the synthesis of spirooxindoles

An iodine-promoted three-component reaction for the construction of spirooxindoles has been developed through the green reaction system of catalytic amount of molecular iodine as an alternative catalyst for Lewis acids. Various substituted isatins were able to react with different cyclic 1,3-dicarbonyls and 4-hydroxyl coumarins through this reaction strategy, which shows good functional group tolerance and efficiency.     

One-pot three-component reaction of fluoroalkanesulfonyl azide, vinyl ether and aldehyde: the formation of polysubstituted fluorinated oxazolidines

Efficient and diastereoselective synthesis of highly substituted fluorinated oxazolidines was achieved via a one-pot three-component reaction of fluoroalkanesulfonyl azides 1, vinyl ether 2 and various aldehydes at 0 °C within 10 min in moderate to good diastereoselectivities (syn/anti). A competing process could be involved in the initial step and an unstable fluorinated aziridine was postulated as the intermediate for these reactions. Additionally, rational transition states were also proposed to elucidate the diastereoselectivities. This synthetic method provides a convenient and expeditious access to N-per(poly)fluoroalkanesulfonyl oxazolidines.     

An unexpected multi-component reaction to synthesis of 3-(5-amino-3-methyl-1H-pyrazol-4-yl)-3-arylpropanoic acids in ionic liquid

A new, one-pot, four-component condensation of 3-methyl-1H-pyrazol-5(4H)-one, ammonium acetate, aromatic aldehydes, and meldrum’s acid in [bmim]BF₄ as solvent is described for the synthesis of 3-(5-amino-3-methyl-1H-pyrazol-4-yl)-3-arylpropanoic acid derivatives. This methodology resulting in excellent isolated yields in short reaction time is characterized by simple work up procedure and little environmental impact.     

Recyclable fluorous organocatalysts promoted three-component reactions of pyruvate,aldehyde and amine at room temperature

A new fluorous imine carbothioate has been prepared as an organocatalyst for the synthesis of pyrrol-2-ones via the cyclo-condensation reaction of aldehydes, amines, and pyruvate at room temperature. The fluorous catalyst can be easily recovered from the reaction mixture by simple fluorous solid-phase extraction (F-SPE) and used for next run reaction without further purification.     

New routes for the synthesis of 3- and 5-substituted 2(1H)-pyrazinones

Various 3-(hetero)aryl, 3-alkyl and 3-alkenyl-2(1H)-pyrazinones were prepared by applying the Suzuki and Heck reaction methodology to 3,5-dichloro-2(1H)-pyrazinones. Furthermore, following hydrogenolysis of the 5-chloro substituent and regioselective 5-bromination, this palladium-catalysed cross-coupling approach could be extended to the synthesis of the analogous 5-substituted 2(1H)-pyrazinones.     

A novel synthesis of diverse 2-amino-5-hydroxy-4H-chromene derivatives with a spirooxindole nucleus by Ca(OH)2-mediated three-component reactions of substituted resorcinols with isatins and malononitrile

An efficient and facile one-pot synthesis is described for the preparation of novel 2-amino-5-hydroxy-4H-chromene derivatives with a spirooxindole nucleus using Ca(OH)₂-mediated three-component reactions of substituted resorcinols with isatins and malononitrile. This simple method provided a variety of biologically interesting diverse 2-amino-5-hydroxy-4H-chromene derivatives in moderate yields under mild reaction conditions.     

Click chemistry for the synthesis of 5-substituted 1H-tetrazoles from boron-azides and nitriles

A novel and metal free catalysis of synthesizing 5-substituted 1H-tetrazoles through 1,3-dipolar cycloaddition of boron-azides and nitriles is reported with broad substrate scope and excellent yields.     

A microwave-assisted, copper-catalyzed three-component synthesis of dihydropyrimidinones under mild conditions

The synthesis of dihydropyrimidinones via a clean multi-component Biginelli reaction under microwave irradiation is reported. The copper-catalyzed process proved to be simple, efficient, economical, and environmentally friendly.     

Novel Biginelli-like three-component cyclocondensation reaction: efficient synthesis of 5-unsubstituted 3,4-dihydropyrimidin-2(1H)-ones

Iron (III) catalyzed the three-component Biginelli-like cyclocondensation reaction efficiently in acetonitrile to afford the corresponding 5-unsubstituted 3,4-dihydropyrimidin-2-(1H)-ones in high yields. The first Biginelli-like reactions of urea, aldehydes and ketones were furnished important new 3,4-dihydropyrimidin-2-(1H)-ones derivatives suitable for further study.     

A novel one pot multi-component strategy for facile synthesis of 5-aryl-[1,2,4]triazolidine-3-thiones

We have disclosed an efficient, one pot, novel multi-component approach for the synthesis of 5-aryl-[1,2,4]triazolidine-3-thiones from aldehyde, hydrazine hydrate, and trimethylsilyl isothiocyanate (TMSNCS) in the presence of catalytic amount of sulfamic acid. High yields, easy work-up procedure, no chromatographic separation, and novelty in multi-component strategy are the main merits of the present strategy.     

Combinatorial synthesis of 4-oxo-4H-imidazo[1,5-a]quinoxalines and 4-oxo-4H-pyrazolo[1,5-a]quinoxalines

A combinatorial synthetic route yielding imidazo[1,5-a]quinoxalines and pyrazolo[1,5-a]quinoxalines is described. The use of 2-fluoroaniline and 1H-imidazole-4-carboxylic acid, respectively, 1H-pyrazole-3-carboxylic acid in the Ugi-reaction (U-4CR) followed by a nucleophilic aromatic substitution (S_NAr) affords the imidazo- as well as the pyrazolo-[1,5-a]quinoxaline moiety in good yield and high diversity.     

Application of p-TSA in the one pot synthesis of N-methyl-3-nitro-aryl-benzo[4,5]imidazo[1,2-a]pyrimidin-2-amine

A simple, efficient, eco-friendly, and cost-effective method has been developed for the synthesis of N-methyl-3-nitro-aryl-benzo[4,5]imidazo[1,2-a]pyrimidin-2-amine derivatives using 2-aminobenzimidazole, aldehydes and (E)-N-methyl-1-(methylthio)-2-nitroethenamine, in the presence of catalytic amount of p-toluenesulfonic acid (p-TSA) in ethanol at 80?°C conditions. The advantages of this method are the use of an inexpensive and readily available catalyst, shorter reaction times, a wide range of functional group tolerance, and high yield of products via a simple experimental and work-up procedure.     

One-pot synthesis of N-protected α-amino aldehyde acetals from three-component reaction of fluoroalkanesulfonyl azide, vinyl ether and alcohol

A facile one-step method has been developed for the synthesis of N-protected α-amino aldehyde acetals in moderate to good yields by three-component reaction of fluoroalkanesulfonyl azides, vinyl ethers and alcohol at 0 °C within 10 min. This practical synthetic method provides a convenient and expeditious access to N-per(poly)fluoroalkanesulfonyl α-amino aldehyde acetals.