Synlett 2024; 35(12): 1429-1435
DOI: 10.1055/a-2184-4836
letter

A Study on the Diazo-Transfer Reaction Using o-Nitrobenzenesulfonyl Azide

Sungduk Gwak
,
Ji Hye Lee
,
,
Hogyu Han

H.H. is grateful for the financial support from the National Research Foundation (NRF) of Korea funded by the Ministry of Science and ICT (NRF2021R1A2C1094754).


Preview

Abstract

15N-Labeled azides have a great potential as practical and effective tags for vibrational probing and hyperpolarized magnetic resonance imaging of biomolecules. They can be synthesized by reaction of primary amines with a 15N-labeled diazo-transfer reagent. TfNN15N, a γ-15N-labeled diazo-transfer reagent, was developed to prepare β-15N-labeled azides; these are vibrational probes devoid of strong spectral interference by Fermi resonance. To overcome the stability and safety problems associated with TfNN15N, there is a strong demand for the development of a novel γ-15N-labeled diazo-transfer reagent. We present a study on the diazo-transfer reaction using o-nitrobenzenesulfonyl azide (o-NsN3). o-NsNN15N, a γ-15N-labeled diazo-transfer reagent, was newly developed and found to be better than TfNN15N with respect to its physicochemical properties and ease of synthesis. Unlike TfNN15N, however, o-NsNN15N was found to afford a mixture of β- and γ-15N-labeled azides rather than the β-15N-labeled azide alone. A mechanism for the diazo-transfer reaction of o-NsNN15N with primary amines is proposed to explain the formation of such isotopomeric mixtures.

Supporting Information



Publication History

Received: 21 April 2023

Accepted after revision: 29 September 2023

Accepted Manuscript online:
29 September 2023

Article published online:
30 November 2023

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