The microwave-assisted synthesis of 5-substituted 1H-tetrazoles via [3+2] cycloaddition over a heterogeneous Cu-based catalyst: application to the preparation of ¹³N-labelled tetrazoles

Abstract

The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of a new CuII catalyst in N-methyl-2-pyrrolidone (NMP) to give the corresponding 5-substituted 1H-tetrazoles.

Chemie der Positronenemissionstomographie: Aktuelle Fortschritte bei 11C‐, 18F‐, 13N‐ und 15O‐Markierungsreaktionen

“…[ 13 N]NO 2 − wurde auch verwendet, um 13 N‐markierte Diazo‐ und Azidoverbindungen über ein Diazoniumintermediat zu erhalten. Die resultierenden 13 N‐markierten Azidoverbindungen können dann in Cyclisierungsreaktionen eingesetzt werden, um [ 13 N]Triazole, [ 13 N]Tetrazole und das Furaxananalogon [ 13 N]PRG150 zu bilden (Schema C) . Über weitere 13 N‐Markierungsagenzien wie [ 13 N]N 2 und [ 13 N]N 2 O wurde ebenfalls berichtet …”

Chemistry for Positron Emission Tomography: Recent Advances in 11C‐, 18F‐, 13N‐, and 15O‐Labeling Reactions

“…[217,219] Forexample,GSNO,amost widely studied S-nitrosothiol, was synthesized in 24 %RCY. [217] [ 13 N]NO 2 À is also used to prepare 13 N-labeled diazo [220,221] and azido [222] compounds via ad iazonium intermediate.T he ensuing 13 Nlabeled azido compounds could be further used in cyclization reactions to form [ 13 N]triazoles, [223] [ 13 N]tetrazoles, [224] and the furaxan analogue [ 13 N]PRG150 (Scheme 37 C). [225] Other 13 Nlabeling agents,s uch as [ 13 N]N 2 and [ 13 N]N 2 O, were also reported.…”

β‐Cyclodextrin: A Green and Efficient Supramolecular Catalyst for Organic Transformations

“…Sharpless and co‐workers reported a “click” chemistry approach for synthesis of tetrazoles by [2+3] cycloaddition of nitriles and NaN 3 using stoichiometric amounts or 50 mol % of Zn(II) salts,, but still requires tedious time consuming steps such as removal of zinc salts from acidic products. Several new pathways have been developed such as use of metal complexes as a catalyst, use of TMSN 3 −TBAF, micellar media and ionic liquids, Zn/Al‐hydrocalcite, Sb 2 O 3 , Mesoporous ZnS nanospheres, silica sulfuric acid, metal modified clay catalyst, ZnO in microwave, ZnCl 2 under solvent free condition, ZnBr 2 in microwave, use of clay‐Montmorillonite K‐10, Kaoline,, use of various azide salts, microwave irradiation,, Et 3 N.HCl in nitrobenzene under microwave irradiation., CdCl 2, FeCl 3 −SiO 2 as acidic heterogeneous catalyst, iodine or silica supported sodium hydrogen sulfate (NaHSO 4 ⋅ SiO 2 ), CoY zeolite, using copper acetate, InCl 3 , copper catalyzed microwave irradiation, sulfamic acid, etc. However, some methods still require long reaction times to achieve reasonable yields and tedious work‐up and purification of products.…”