- A 15N NMR investigation of a series of benzotriazinones and related antitumour heterocycles
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A series of 3-substituted 1,2,3-benzotriazin-4-ones, 1 and 2, were synthesized by standard methods and the 15N 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 15N 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
- Vaughan, Keith,Wilman, Derry E. V.,Wheelhouse, Richard T.,Stevens, Malcolm F. G.
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p. 300 - 302
(2007/10/03)
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- Activation of carboxylic acids as their active esters by means of tert-butyl 3-(3,4-dihydrobenzotriazine-4-on)yl carbonate
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Carboxylic acids were activated in the presence of DMAP with tert-butyl carbonates (BOC-OX) 1, which were prepared in situ by reaction of X-OH and di-tert-butyl dicarbonate (BOC2O). The most efficient active carbonate proved to be tert-butyl 3-(3,4-dihydrobenzotriazine-4-on)yl carbonate 1a, leading to efficient formation of benzotriazinonyl esters 3 and 6, which are intermediates in reactions with primary and secondary amines to afford amides or peptides in good yield. By-products in the formation of 3 or 6 are the environmentally safe tert-BuOH and CO2. The hindered amino acid AIB also forms a dipeptide in good yield.
- Basel, Yochai,Hassner, Alfred
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p. 2529 - 2533
(2007/10/03)
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- Glycosylhydrazides, a New Class of Sugar Surfactant. Preparation and Amphiphilic Properties of 1-Glycosyl-2-Acylhydrazines
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The synthesis and the amphiphilic properties of 1-glycosyl-2-acylhydrazines are described. This new class of surfactants, referred to as glycosylhydrazides, is easily available from a reducing sugar and hydrazides without protection. Seven hydrazides having an alkyi chain of up to fourteen carbon atoms, arc coupled with glucose giving 1-glucosyl-2-acylhydrazines in good yields; 1-maltosyl-2-octanoylhydrazine, as a typical disaccharide-based surfactant, is prepared as well. Critical micellar concentrations of these surfactants range from 0.04 to 252 mM.
- Auge, Jacques,Lubin-Germain, Nadege
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p. 378 - 392
(2007/10/03)
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