Tautomerism of4,4′-dihydroxy-1,1′-naphthaldazine studied byexperimental and theoretical methods

Tautomerism of 4,4′-dihydroxy-1,1′-naphthaldazine studied by experimental and theoretical methods

BACKGROUND The title compound belongs to the class of bis-azomethine pigments. On the basis of comparative studies on similar structures, insight into the complex excited state dynamics of such compounds has been gained. It has been shown, for example, that only compounds that possess hydroxyl groups are fluorescent, and that the possibility for cis-trans isomerisation and/or bending motions of...

Tautomerism: Introduction, History, and Recent Developments in Experimental and Theoretical Methods

Prototropic tautomerism, defined by one of its early investigators as ‘‘the addition of a proton at one molecular site and its removal from another’’ [1], and hence clearly distinguished from ionization, is one of the most important phenomena in organic chemistry despite the relatively small proportion of molecules in which it can occur. There are several reasons for this. Enantiomers, or cis a...

Tautomerism in 11-Hydroxyaklavinone: A DFT Study

The antharquinone-based chromophore of 11-hydroxyaklavinone is present in the structure of an anticancer agent, daunomycin. On the other hand, aklavinone is the parent aglycone of certain anthracycline antibiotics that possess anti-cancer activity too. The structures of aklavinone and its 11-hydroxy derivative have many -OH groups, and two keto groups which may take place in certain tautomeric ...

Synthesis of new unsymmetrical 4,5-dihydroxy-2-imidazolidinones. Dynamic NMR spectroscopic study of the prototropic tautomerism in 1-(2-benzimidazolyl)-3-phenyl-4,5-dihydroxy-2-imidazolidinone.

The acid-catalyzed cyclocondensation in refluxing acetonitrile of aqueous glyoxal with N-heteroaryl-N'-phenylureas 4a-f (heteroaryl = 2-thiazolyl, 2-pyrimidinyl,2-pyrazinyl, 2-pyridinyl, 3-pyridinyl and 2-benzimidazolyl) led to the formation of the corresponding 1-heteroaryl-3-phenyl-4,5-dihydroxy-2-imidazolidinones 5a-f. All the products were characterized by elemental and spectroscopic analys...

Computational Methods 11 - 04 and 11 Yxx