61799-01-7Relevant articles and documents
Borane adducts of punicine and of its dehydroxy derivatives (pyridinium-1-yl)-2- and 3-phenolates
Freese, Tyll,Hübner, Eike G.,Herzberger, Colin,Lederle, Felix,Liu, Ming,Namyslo, Jan C.,Nieger, Martin,Otto, Christian F.,Schmidt, Andreas
, (2020/10/13)
The natural product punicine (Punica granatum) exists in two tautomeric forms, the cross-conjugated mesomeric betaine 1-(pyridinium-1-yl)-2-hydroxy-phenyl-5-olate and the conjugated mesomeric betaine 1-(pyridinium-1-yl)-5-hydroxy-phenyl-2-olate. Punicine
SYNTHESIS AND SOLVATOCHROMIC AND ACID-BASE REACTIONS OF A BETAINE AND SALTS OF 4-N-PYRIDINIUMCATECHOL
Neiland, O. Ya.,Kraupsha, I. L.,Gudele, I. Ya.
, p. 1428 - 1434 (2007/10/02)
Oxidation of catechol by phenyliodosyldiacetate in the presence of pyridine gives 4-N-pyridiniumcatechol salts whose structures are confirmed by an independent synthesis from 2,2-dimethyl-5-aminobenzodioxole.The spectroscopically determined ionization constants for the 4-N-pyridiniumcatechol cation depend on the nature of the buffer cation solution (sodium, ammonium, tetraethylammonium).The large solvatochromic shift in the long wavelength absorption band of the betaine of 4-N-pyridinium-catechol followed the empirical scale of solvent polarity ENT.Introduction of the N-pyridinium group in position 4 increases the acidity of the catechol by 2.7 pK units, which is an almost identical effect to the introduction of a 4-nitro group.However, the solvatochromism for the anion of 4-nitrocatechol is insignificant.The compounds were characterized by their 1H NMR and IR spectra.
Reaction of Bromine with Dihydric Phenols in Presence of Heterocyclic Tertiary Bases
Jain, M. L.,Soni, R. P.,Saxena, J. P.
, p. 718 - 720 (2007/10/02)
A number of N-(dihydroxyphenyl)ammonium bromides (I, II) have been synthesised and their structure ascertained through elemental analyses, IR and PMR spectral data.
