Related Experiment Video
Updated: Nov 8, 2025

Nitropeptide Profiling and Identification Illustrated by Angiotensin II
Published on: June 16, 2019
The Hantzsch reaction for nitrogen-13 PET: preparation of [13N]nifedipine and derivatives
Julia E Blower1, Michelle T Ma1, Fahad A I Al-Salemee1
1King's College London, School of Biomedical Engineering and Imaging Sciences, Department of Imaging Chemistry and Biology, 4th Floor Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK. julia.blower@kcl.ac.uk antony.gee@kcl.ac.uk.
Abstract:
Nitrogen-13 is an attractive but under-used PET radionuclide for labelling molecules of biological and pharmaceutical interest, complementing other PET radionuclides. Its short half-life (t1/2 = 9.97 min) imposes synthetic challenges, but we have expanded the hitherto limited pool of 13N labelling strategies and tracers by adapting the multicomponent Hantzsch condensation reaction to prepare a library of 13N-labelled 1,4-dihydropyridines from [13N]ammonia, including the widely-used drug nifedipine. This represents a key advance in 13N PET radiochemistry, and will serve to underpin the renewed interest in clinical opportunities offered by short-lived PET tracers.
Related Concept Videos
2° Amines to N-Nitrosamines: Reaction with NaNO2
Diazonium Group Substitution: –OH and –H
Preparation of Nitriles
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by...
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Other Nuclides: 31P, 19F, 15N NMR
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a...

