TY - JOUR
T1 - Combined XRD-paramagnetic 13C NMR spectroscopy of 1,2,3-triazoles for revealing copper traces in a Huisgen click-chemistry cycloaddition. A model case
AU - Canseco-González, Daniel
AU - Rodríguez De La O, José Luis
AU - Herbert-Pucheta, José Enrique
N1 - Publisher Copyright:
© 2019 Daniel Canseco-Gonzalez et al., published by De Gruyter.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Copper-catalyzed Alkyne-Azide Cycloaddition (CuAAC) click chemistry robustness has been demonstrated over recent years to produce 1,2,3-triazoles with excellent yields at mild conditions with simple purification methods. However, the consequences of having copper paramagnetic traces in final products, which complicate spectroscopic assignments and can produce inaccurate conclusions, has been scarcely discussed. Herein we present a strategy that combines X-Ray Diffraction (XRD) with 13C- paramagnetic Nuclear Magnetic Resonance spectroscopy, in order to demonstrate the presence of paramagnetic metal traces at standard Huisgen synthesis and purification conditions. We also demonstrate that the derivatization of 1,4-disubstituted-1,2,3- triazoles to produce 1,3,4,-trisubstituted-1,2,3.triazolium salts, promotes an efficient removal of Cu(II/I) moieties. Evidence of paramagnetic metal moieties is given using XRD structural analysis of abnormalities in torsional angles between substituents and the 1,2,3-triazole center, in parallel to 13C- paramagnetic NMR chemical shift and line width analysis. As model systems to demonstrate the importance of characterizing paramagnetic traces, we present the synthesis of novel 1-((3s,5s,7s)-adamantan- 1-yl)-4-cyclopropyl-1H-1,2,3-triazole and its derivatized 1-((3s,5s,7s)-adamantan-1-yl)-4-cyclopropyl-3-methyl- 1H-[1,2,3]-triazol-3-ium triflate salt.
AB - Copper-catalyzed Alkyne-Azide Cycloaddition (CuAAC) click chemistry robustness has been demonstrated over recent years to produce 1,2,3-triazoles with excellent yields at mild conditions with simple purification methods. However, the consequences of having copper paramagnetic traces in final products, which complicate spectroscopic assignments and can produce inaccurate conclusions, has been scarcely discussed. Herein we present a strategy that combines X-Ray Diffraction (XRD) with 13C- paramagnetic Nuclear Magnetic Resonance spectroscopy, in order to demonstrate the presence of paramagnetic metal traces at standard Huisgen synthesis and purification conditions. We also demonstrate that the derivatization of 1,4-disubstituted-1,2,3- triazoles to produce 1,3,4,-trisubstituted-1,2,3.triazolium salts, promotes an efficient removal of Cu(II/I) moieties. Evidence of paramagnetic metal moieties is given using XRD structural analysis of abnormalities in torsional angles between substituents and the 1,2,3-triazole center, in parallel to 13C- paramagnetic NMR chemical shift and line width analysis. As model systems to demonstrate the importance of characterizing paramagnetic traces, we present the synthesis of novel 1-((3s,5s,7s)-adamantan- 1-yl)-4-cyclopropyl-1H-1,2,3-triazole and its derivatized 1-((3s,5s,7s)-adamantan-1-yl)-4-cyclopropyl-3-methyl- 1H-[1,2,3]-triazol-3-ium triflate salt.
UR - http://www.scopus.com/inward/record.url?scp=85076189833&partnerID=8YFLogxK
U2 - 10.1515/hc-2019-0018
DO - 10.1515/hc-2019-0018
M3 - Artículo
AN - SCOPUS:85076189833
SN - 0793-0283
VL - 25
SP - 98
EP - 106
JO - Heterocyclic Communications
JF - Heterocyclic Communications
IS - 1
ER -