TBAF-Catalyzed Synthesis of 5-Substituted 1<i>H</i>-Tetrazoles under Solventless Conditions

Amantini, David; Beleggia, Romina; Fringuelli, Francesco; Pizzo, Ferdinando; Vaccaro, Luigi

doi:10.1021/jo0499468

Cited by 274 publications

(139 citation statements)

References 10 publications

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“…The resulting DMAP-IL (dimethylamino pyridinium with uoride counter anion) could effectively serve as a substitute for tetra butyl ammonium uoride (TBAF), a well-known catalyst and IL that has been used to promote different chemical reactions (Scheme 1). [13][14][15] The DMAP-based ionic liquids (2, 3) with uoride counter anions were then investigated for their efficiency as catalysts for synthesis of tetrahydro-1H-carbazole (indoles)/methyl tetrahydro-1H-carbazole (indolenines) (Fig. 2a) and 1H-tetrazole (Fig.…”

Section: 12mentioning

confidence: 99%

“…They used tetrabutyl ammonium uoride (TABF) as catalyst for tetrazole formation by reacting nitrile species with trimethylsilyl azide. 15 In the context of developing metal free click reaction of tetrazole formation, we synthesized new N,N-dimethylamino pyridinium cation with uoride anion as alternate of TBAF in 1H-tetrazole synthesis due to their easy handling and rapid preparation from commercially available solid 4-dimethylaminopyridine. The new DMAP-based ionic liquids were successfully employed them as catalysts with minimum loading (0.2 equivalent) tetrazole formation.…”

Section: 27mentioning

confidence: 99%

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N,N-Dimethylpyridin-4-amine (DMAP) based ionic liquids: evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1H-tetrazole synthesis

et al. 2017

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The last few decades have seen a rapid increase in the use of ionic liquids (ILs) as a green alternative to traditional solvents in organic synthesis. The use of ILs as catalysts has also increased in recent years.Herein we the report synthesis of new N,N-dimethylpyridin-4-amine (DMAP) based ionic liquids (ILs) as new and efficient catalysts for the facile synthesis of indoles (via Fischer indole synthesis), and 1H-tetrazoles (via click chemistry). The method is environmentally friendly, requiring only minimum catalyst loading (0.2 equiv. for Fischer indole synthesis). In the case of 1H-tetrazole formation (via click chemistry), the reaction was carried out under a solvent free environment. Moreover, thermal studies (TGA, DTG and DSC) of DMAP-ILs (2, 3) have also been carried out to elicit their stability for temperature dependent reactions. Application of molecular dynamics simulations provided valuable insights into the structural and transport properties of these ionic liquids. An MP2 method was applied to evaluate the stability of the compound via binding energy calculations.

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Section: 12mentioning

confidence: 99%

Section: 27mentioning

confidence: 99%

N,N-Dimethylpyridin-4-amine (DMAP) based ionic liquids: evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1H-tetrazole synthesis

et al. 2017

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“…A number of methods have been reported for the preparation of tetrazoles, among; one of the major convenient synthetic routes to tetrazole formation is the [3+2] cycloaddition of azide to corresponding nitriles [22]. Many synthetic methods were introduced for this transformation, requires amine salts [23], strong Lewis acid [24,25] and toxic metals [25]. The generated hydrazoic acidin this transformation is highly toxic and explosive.…”

Section: Introductionmentioning

confidence: 99%

ZnBr2-SiO2 catalyzed green synthesis of tetrazoles: Molecular docking and antioxidant activity studies

et al. 2017

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A series of 5-substituted and 1,5-disubstituted tetrazoles were synthesized in high yields from various biologically active substituted nitriles with sodium azide under heterogeneous catalysed (ZnBr2-SiO2) [2+3] cycloaddition conditions. This reaction gave an excellent yield in the presence of catalytic amount of 0.2 g of ZnBr2-SiO2, glycerol solvent system under microwave irradiation conditions. All the prepared compounds were characterized by elemental analysis 1 H NMR, 13 C NMR, FT-IR, and mass spectral data. The newly synthesized compounds were investigated for their respective molecular target using molecular docking studies. The results reveal that compounds 5a, 5c, 5e and 3e have conferred with multi target property. The compounds 5a, 5c and 5e have shown the highest binding affinities of -10.1, -9.7 and -10.6 with reverse transcriptase, -8.5, -8.2 and -8.9 with Aurora B, respectively. The compounds 5a, 5e and 3e have shown -8.9, -8.5 and 8.4 with Aromatase, respectively. In addition, the antioxidant activity data reveals that all the compounds showed good antioxidant activity, particularly the compounds 3d, 5d, and 5e exhibited promising radical scavenging activity.

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“…22 The "click" chemistry approach utilizing zinc catalysis in aqueous solution is a magnificent improvement over latter methods, 23,24 but occasionally still requires the tedious and time-consuming removal of zinc salts from the acidic products. Stoichiometric amounts of inorganic salts and metal complexes 25 as catalysts, use of TMSN 3 and TBAF 26 instead of metal salts under solvent-free conditions in micellar media and ionic liquids, and use of various catalysts [27][28][29][30][31] such as BF 3 .OEt 2 , 21 Pd(OAc) 2 /ZnBr 2 , 27 Yb(OTf) 3 , 28 Zn(OTf) 3 , 29 AlCl 3,30 and Pd (PPh 3 ) 4 31 were also employed for the same purpose. However, a drawback of these homogeneous catalytic processes lies in the tedious separation and recovery of the catalysts.…”

Section: Introductionmentioning

confidence: 99%

A novel approach for the synthesis of 5-substituted-1H-tetrazoles

Akhlaghinia¹,

Rezazadeh²

2012

J. Braz. Chem. Soc.

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Uma série de 1H-tetrazóis-5-substituídos (RCN 4 H) foi sintetizada pela reação de cicloadição de diferentes aril e alquil nitrilas com azida de sódio em DMSO, usando CuSO 4 •5H 2 O como catalisador. Uma grande variedade de aril nitrilas sofreu cicloadição [3+2], obtendo-se os correspondentes tetrazóis sob condições reacionais brandas. O catalisador utilizado é obtido facilmente e ambientalmente correto. Tempos de reação curtos, bons a excelentes rendimentos, processo seguro e simples tornam este método uma contribuição atrativa e útil à presente síntese orgânica de 1H-tetrazóis-5-substituídos.A series of 5-substituted-1H-tetrazoles (RCN 4 H) have been synthesized by cycloaddition reaction of different aryl and alkyl nitriles with sodium azide in DMSO using CuSO 4 •5H 2 O as catalyst. A wide variety of aryl nitriles underwent [3+2] cycloaddition to afford tetrazoles under mild reaction conditions in good to excellent yields. The catalyst used is readily available and environmentally friendly. Short reaction times, good to excellent yields, safe process and simple workup make this method an attractive and useful contribution to present organic synthesis of 5-substituted-1H-tetrazoles.Keywords: 5-substituted-1H-tetrazole, arylnitriles, sodium azide, CuSO 4 •5H 2 O, cycloaddition reaction IntroductionThe chemistry of heterocyclic compounds has been an interesting field of study for a long time. Tetrazoles as a group of heterocyclic compounds are reported to possess a broad spectrum of biological activities such as antibacterial, 1 antifungal, 2 antiviral, 3-5 analgesic, 6,7 anti-inflammatory, [8][9][10] [41][42][43][44][45][46][47][48] were commonly used to improve the catalytic abilities of montmorillonites. These methods require a large excess of sodium azide, longer reaction time, and expensive metals. Moreover, the cycloaddition is too slow A Novel Approach for the Synthesis of 5-Substituted-1H-tetrazoles J. Braz. Chem. Soc. 2198 to be synthetically useful except when strong electronwithdrawing groups activate the nitrile compounds.Today's stringent environmental and legislative concerns demand for the green methods that reduce the use of toxic and corrosive reagents and stop the formation of inorganic wastes. 49 However, it has been also observed that the catalysts employed are not always eco-friendly and because of this, serious environmental pollution often results. Therefore, in the area of green synthesis, the development of environmentally friendly alternatives is desirable for the synthesis of tetrazoles. 50 Recently, we have studied the application of cupric sulfate pentahydrate in the trimethylsilylation of alcohols and phenols, 51 and perceived that cupric sulfate pentahydrate as a mild Lewis acid, which is readily available, might be a useful catalyst for the synthesis of 5-substituted-1H-tetrazoles. In this paper we report a new process for the synthesis of 5-substituted 1-H-tetrazoles using cupric sulfate pentahydrate as a safe, environmentally benign, and inexpensive catalyst. ExperimentalThe p...

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TBAF-Catalyzed Synthesis of 5-Substituted 1H-Tetrazoles under Solventless Conditions

Abstract: Tetrabutylammonium fluoride (TBAF) is an efficient catalyst in the [3 + 2] cycloaddition reaction of organic nitriles 1 with trimethylsilyl azide (TMSN(3)) in solventless conditions. The corresponding 5-substituted 1H-tetrazoles 2 were obtained under mild conditions and in 80-97% yields.

Cited by 274 publications

References 10 publications

N,N-Dimethylpyridin-4-amine (DMAP) based ionic liquids: evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1H-tetrazole synthesis

N,N-Dimethylpyridin-4-amine (DMAP) based ionic liquids: evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1H-tetrazole synthesis

ZnBr2-SiO2 catalyzed green synthesis of tetrazoles: Molecular docking and antioxidant activity studies

A novel approach for the synthesis of 5-substituted-1H-tetrazoles

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