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 tetrazolesElectronic supplementary information (ESI) available: Characterization of compounds 2a-2k. See DOI: 10.1039/c7nj00568g

• Main Authors: Joshi, Sameer M, Mane, Rasika B, Pulagam, Krishna R, Gomez-Vallejo, Vanessa, Llop, Jordi, Rode, Chandrashekhar
• Format: Journal Article
• Language: English
• Published: 07.08.2017
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c7nj00568g

The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of a new Cu II catalyst in N -methyl-2-pyrrolidone (NMP) to give the corresponding 5-substituted 1 H -tetrazoles. The desired tetrazoles were obtained in high yields within 3-30 min by employing controlled microwave heating. The reaction most probably proceeds through the activation of the nitrile groups by the Cu II species, followed by a successive [3+2] cycloaddition with the sodium azide. The good performance of the catalyst enabled the preparation of selected tetrazoles labelled with the positron emitter nitrogen-13 even under conventional heating. The short reaction time, simple work-up procedure, and recyclability of the catalyst are advantages of the method reported here. The [3+2] cycloaddition between various nitriles and sodium azide proceeds smoothly in the presence of a new Cu II catalyst in N -methyl-2-pyrrolidone (NMP) to give the corresponding 5-substituted 1 H -tetrazoles.