4536-70-3Relevant academic research and scientific papers
Two azo pigments based on Β-naphthol
Schmidt, Martin U.,Bruening, Juergen,Wirth, Daniela,Bolte, Michael
experimental part, p. o474-o477 (2009/02/06)
There has been much discussion in the literature of the azo-hydrazone tautomerism of pigments. All commercial azo pigments with Β-naphthol as the coupling compound adopt the hydrazone tautomeric form (Ph - NH - N=C) in the solid state. In contrast, the red pigments 1-[4-(dimethyl-amino)phenyl-diazen- yl]-2-naphthol, C18H17N3O, (1a), and 1-[4-(di-ethyl-amino)phenyl-diazen-yl]-2-naphthol, C20H 21N3O, (1b), have been reported to be azo tautomers or a mixture of azo and hydrazone tautomers in the solid state. To prove these observations, both compounds were synthesized, recrystallized and their crystal structures redetermined by single-crystal structure analysis. Difference electron-density maps show that the H atoms of the hydroxyl groups are indeed bonded to the O atoms. Nevertheless, a small amount of the hydrazone form seems to be present. Hence, the compounds are close to being real azo compounds. Compound (1a) crystallizes with a herring-bone structure and compound (1b) forms a rare double herring-bone structure.
TAUTOMERIC TRANSFORMATIONS AND COLOR OF MONOAZO DYES. I. DYES BASED ON 3-SUBSTITUTED 2-NAPHTHOLS
Traven', V. F.,Kostyuchenko, E. E.,Mkhitarov, R. A.,Men'shikova, N. F.,Oreshin, M. M.,Stepanov, B. I.
, p. 922 - 930 (2007/10/02)
1-(4-X-phenylazo)-3-Y-2-naphthols, in which X = OMe, NEt2, NHC6H4OMe-4; Y = H, COOH, CONHC6H4OMe-4, CONH(CH2)2OH, OH, COOEt, CON(CH2)5, and also 1-(4-diethylaminophenylazo)-3-Y-2-hydroxybenzocarbazoles, in which Y = COOH, CONHC6H4OMe-4, COOMe, were synthe
