Synthesis of tetrazoles via isocyanide-based reactions

Abstract

The aim of this review is providing an overview of the various representative literature procedures for the preparation of tetrazoles via isocyanide-based reactions. These reactions have been divided into four classes including two-component reactions (2CRs), Passerini-azide three-component reactions (PA-3CRs), Ugi-azide four-component reactions (UA-4CRs) and Ugi-azide three-component reactions (UA-3CRs).Scheme 1 Tetrazoles are bioisosteres of carboxylic acids and cisamides.Scheme 2 Cycloaddition reaction between isocyanides and HN 3 . Scheme 3 Synthesis of tetrazoles 3 under acid catalysis. Scheme 4 Synthesis of optically pure 1-STs. This journal is Scheme 8 Four-component synthesis of alkoxylated tetrazole 15 and a-alkoxyamides 16. Scheme 9 Synthesis of tetrazoles via intramolecular MCR of cyclic acetals. Scheme 10 The UA-4CR as a variation of the classical Ugi-reaction. 60942 | RSC Adv., 2015, 5, 60938-60955 This journal is Scheme 11 Synthesis of quinolin-4-amine-based tetrazoles 19. Scheme 12 Synthesis of 1,5-disubstituted aminomethyltetrazole derivatives 23. Scheme 13 A UA-4CR repetitive product. Scheme 14 Desosamine containing tetrazoles. This journal is Scheme 15 UA-4CR synthesis of tetrazolic analogues 28 of chalcones 27. Scheme 16 Synthesis of 4-aminoquinoline-tetrazole derivatives 30. 60944 | RSC Adv., 2015, 5, 60938-60955 This journal is Scheme 17 Synthesis of tetrazoles 32 in the presence of MgBr 2 $2Et 2 O. Scheme 18 The preparation of the tetrazole 33 by an UA-4CR. Scheme 19 Diastereoselective synthesis of a-hydrazine tetrazoles 32 via a UA-MCR. This journal isScheme 20 UA-4CRs for the synthesis of a-amino acid analogue tetrazoles 37.Scheme 21 Synthesis of tetrazolyl-isoindolinones 40 via UA-4CR/intramolecular amidation.Scheme 22 Synthesis of bis-3,4-dihydroquinoxalinone and bis-benzodiazepine tetrazoles. Scheme 23 Synthesis of 1,5-DT-hydantoins. 60946 | RSC Adv., 2015, 5, 60938-60955 This journal is Scheme 34 Synthesis of tetrazole-fused diazepinones through UA-MCRs. Scheme 35 Synthesis of tetrazolo-fused benzodiazepinones.Fig. 6 Examples of tetrazolo-fused benzodiazepinones 83 and benzodiazepines 86 and 87. This journal isScheme 41 Proposed mechanism for the formation of 1,5-DTs.Scheme 42 UA-3CR for the synthesis of tetrazolyl-pyridines, -quinoline and -isoquinoline.Scheme 43 Three-component process for the synthesis of 1,5-DT.Scheme 44 U-4C/3-CR for the synthesis of fused 1,5-DSTs.Scheme 45 Synthesis of the 5-halo-1-phenyltetrazoles.This journal is

Length‐Scale‐Dependent Phase Transformation of LiFePO4: An In situ and Operando Study Using Micro‐Raman Spectroscopy and XRD

“…Although multicomponent reactions have lately emerged as a powerful tool in the synthesis of biologically important diverse scaffolds and even though fused tetrazoles possess a wide spectrum of biological activities, only very limited access to these fused tetrazoles is currently possible by a simple one‐pot MCR 1,17. For example, fused tetrazoles are accessible through the isocyanide‐based synthesis of tetrazoles followed by cyclization 18. Using our highly flexible and robust methodology, we foresaw a quick and easy way to access therapeutically interesting complex molecular structures.…”

Isocyanide-based multicomponent reactions in the synthesis of heterocycles

“…The organic segment is connected to the isocyanide group via the nitrogen atom, not via the carbon. They are used as privileged synthons for the synthesis of other organic compounds in particular various heterocycles [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] , frequently via multicomponent reactions (MCRs) namely isocyanide multicomponent reactions (IMCRs) 25,[38][39][40][41][42][43][44][45][46][47][48][49] . Noticeably isocyanides are susceptible to polymerization 50 .…”

Synthesis of α‐Aminonitriles and 5‐Substituted 1H‐Tetrazoles Using an Efficient Nanocatalyst of Fe3O4@SiO2–APTES‐supported Trifluoroacetic Acid

“…Moreover, the existence of electron‐withdrawing groups on the nitriles can further activate it for nucleophilic addition to the carbon in nitriles . An isocyanide‐based multicomponent reaction (Passerini‐azide and Ugi‐azide reactions) is also used for the synthesis of tetrazoles . According to the literature, 5‐substituted and 1‐substituted 1 H ‐tetrazoles have been synthesized using different azide agents (NaN 3 , TMSN 3 , and [bmim]N 3 ) and catalyzed by different systems such as SnCl 2 –SiO 2 , InCl 3 , ZnS nanoparticles (NPs) , Pt NPs@rGO , Cu–MCM‐41 , MCM‐41–SO 3 H , SiO 2 –H 3 BO 3 , Fe 3 O 4 @chitin , and boehmite–Ni .…”