The Synthesis of 5-Substituted 1H-Tetrazoles in Molten Tetrabutylammonium Bromide

Abstract

An economical and environmentally benign method for the synthesis of 5-substituted 1H-tetrazoles has been established. In this protocol, molten tetrabutylammonium bromide (TBAB) is used as both the solvent and catalyst. A mechanism involving the intermediacy of tetrabutylammonium azide (TBAN 3 ) is proposed.

Synthesis of 5‐Substituted‐1H‐Tetrazoles from Nitriles and Azides in a Betaine‐Diol‐Based Deep Eutectic Solvent

“…When acetate-based catalysts, such as Zn(OAc) 2 , Cu(OAc) 2 , and NH 4 OAc, were employed, the yield obtained was unsatisfactory compared to that obtained with the ZnCl 2 catalyst (Table 1, entries [11][12][13].…”

MCM-41-SO3H: as an efficient reusable Nano-ordered heterogeneous catalyst for the synthesis of divers 1- & 5-substituted 1H-tetrazoles

“…In an e ort to develop better reaction conditions, di erent solvents, such as DMSO, H 2 O, CH 3 CN, CHCl 3 , 1,4-dioxan, and toluene ( Table 1, entries [11][12][13][14][15][16], were screened for cycloaddition reaction in the presence of MCM-41SO 3 H as an e ective catalyst. The result indicated that the desired product was obtained in low yield as compared with DMF.…”

“…In comparison to aromatic nitriles, a wide range of alkyl nitriles, such as 4-chloro benzyl cyanide, benzyl cyanide, and malononitrile, react with NaN 3 under the optimized reaction conditions with subsided yield (Table 2 entries [12][13][14].…”

“…Literature reviews indicate that the Huisgen 1,3-Dipolar Cycloaddition of a dipolarophile (e.g., nitrile moiety) with a 1,3-dipolar structure (e.g., sodium azide) in the presence of a broad variety of homogeneous or heterogeneous catalysts such as CdCl 2 [7], Pd(OAc) 2 /ZnBr 2 [8], ZnO, ZnBr 2 , ZnCl 2 /tungstates, Zn/Al hydrotalcite, ZnCl 2 /AlCl 3 /silica, Zn(OTf) 2 , Zn hydroxyapatite, ZnS, Cu(OAc) 2 , Cu 2 O, nano ZnO/Co 3 O 4 , FeCl 3 -SiO 2 , Fe(OAc) 2 , nano CuFe 2 O 4 , BF 3 .OEt 2 , InCl 3 , I 2 , (CH 3 ) 2 SnO, NH 4 Cl, TBAF, TBAB, AgNO 3 , Ag-NPs, copper tri ates, -cyclodextrin, cuttlebone, COY zeolites, Silica Sulfuric Acid, Pd(PPh 3 ) 4 , WAlPO-5 microspheres, Fe 3 O 4 @SiO 2 /salen of Cu(II), B(C 6 F 5 ) 3 , AlCl 3 , Zn-Cu alloy, CAES, CuSO 4 .5H 2 O, and cutlleboneand In(OTf) 3 is a general current mechanism for the synthesis of 1H-tetrazol derivatives [9][10][11][12][13][14][15][16][17][18][19][20].…”

Tetrabutylammonium Bromide (TBAB) Catalyzed Synthesis of Bioactive Heterocycles

“…Xie et al [ 86 ] reported a simple and efficient protocol for the synthesis of a series of 5-substituted 1 H -tetrazoles ( 26 ) with excellent yields from the reactions of aryl nitrile ( 24 ) and sodium azide ( 25 ) in molten tetrabutylammonium bromide at 105 °C ( Scheme 12 ). In this reaction, molten TBAB played a dual role, both as a solvent as well as a catalyst.…”