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A 15N NMR investigation of a series of benzotriazinones and related antitumour heterocycles

✍ Scribed by Keith Vaughan; Derry E. V. Wilman; Richard T. Wheelhouse; Malcolm F. G. Stevens

Publisher
John Wiley and Sons
Year
2002
Tongue
English
Weight
105 KB
Volume
40
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

A series of 3‐substituted 1,2,3‐benzotriazin‐4‐ones, 1 and 2, were synthesized by standard methods and the ^15^N NMR spectra were recorded. All spectra were obtained using the natural abundance of the nitrogen‐15 isotope. The chemical shifts appear in the normal range for N‐1, N‐2 and N‐3 of the triazine ring, and also correlate with the chemical shifts in the spectra of the imidazolotriazinone, 4, and the imidazolotetrazinone, 5. Significantly, the spectra of 1a, 2 and 4, recorded with full NOE, show inversion of the singlet assigned to N‐3, demonstrating that these compounds exist in the tautomeric form shown. The structure of the 4‐iminobenzotriazinone (3) was confirmed by this ^15^N NMR analysis. The spectrum shows a signal for the NH‐bearing imino‐nitrogen atom, which is an inverted singlet in the NOE spectrum, whereas the signal from the N‐3 atom of 3 is not inverted in the NOE spectrum. Copyright © 2002 John Wiley & Sons, Ltd.

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