117286-45-0Relevant academic research and scientific papers
Copper-mediated 3-N-arylation of flavins
Attenberger, Bianca,Schmaderer, Harald,Koenig, Burkhard
, p. 1767 - 1774 (2008/12/22)
A generally applicable method for the direct 3-N-arylation of flavins using arylboronic acids and copper acetate was developed. The reaction conditions were optimized considering the lability of flavins in basic conditions and thermal heating. Donor-and acceptor-substituted arylboronic acids were used yielding 3-N-arylflavins in moderate to good yields by C(aryl)-N(imide) bond formation. UV and fluorescence measurements indicate an orthogonal orientation of the additional aromatic substituent to the flavin ring system. The arene substituent is not electronically coupled to the flavin π-system in the ground state, but electron-rich arene substituents in 3-N position significantly reduce the flavin emission intensity.
Nouvelle voie d'acces aux iso-alloxazines par l'intermediaire d'alkyl-1-amino-2-tetrahydro-1,5,6,7-quinoxaline-3-carbonitriles (ou carboxylate de methyle)
Lacroix, Alain,Schabat, Dominique,Clerin, Daniel,Fleury, Jean-Pierre
, p. 1065 - 1072 (2007/10/02)
A new synthetic approach to iso-alloxazines using 1-alkyl-2-amino-1,5,6,7-tetrahydroquinoxaline-3-carbonitriles (or the corresponding methylcarboxylates) is reported.These key intermediates, accessible in two steps from cyclohexanone-enamines, when treated alkyl(aryl)iso-cyanates, guanidine or alkylchloroformates yield tetrahydro-iso-alloxazine derivatives, which can be dehydrogenated.Thus 3,10-dialkyl, 10-alkyl-3-aryl, 10-alkyl-iso-alloxazines or their 2-imino-4-oxo, 4-imino-2-oxo and 2,4-bisimino derivatives were obtained.The regiospecific aspect of this approach is illustrated by the synthesis of naphto, naphto or dimethyl-7,8 benzo pteridine derivatives.Tautomeric behavior or the tetrahydro intermediates and some limitations of the method are discussed.
