82-49-5Relevant articles and documents
Carbon-carbon cleavage of aryl diamines and quinone formation using sodium periodate: a novel application
Telvekar, Vikas N.,Takale, Balaram S.
experimental part, p. 3940 - 3943 (2010/08/07)
A first novel synthetic utility of sodium periodate for aryl diamine carbon-carbon cleavage is described. Aryl 1,2-diamine compounds were successfully converted into corresponding nitriles, while the developed method is also useful for the preparation of quinones from corresponding aryl 1,4-diamine compounds. The advantages of this protocol are shorter reaction time and mild reaction conditions to obtain moderate to good yields.
Equilibrium and Kinetic Studies of Some Reactions of 1-Anthraquinonesulfenic Acid and Its Methyl Ester
Kice, John L.,Weclas-Henderson, Ludmilla,Kewan, Aly
, p. 4198 - 4203 (2007/10/02)
1-Anthraquinonesulfenic acid (2) is a stable arenesulfenic acid.Its pKa, and the products and kinetics of its reactions, and those of its methyl ester (3), with both a thiol (n-BuSH) and m-chloroperoxybenzoic acid (MCPBA), have been determined.The results are compared with those for the corresponding reactions of two stable areneselenic acids (1a and 1b).The pKa of 2 (7.51) shows it to be ca. 3 pK units stronger acid than o-O2NC6H4SeOH (1a).Reaction of 2 and 3 with n-BuSH occurs at comparable rates and gives n-butyl 1-antraquinonyl disulfide (5) via a reactionthat is acid catalyzed.The rate of reaction of 2 with the thiol is ca. 104 slower than the rate of reaction of the structurally analogous areneselenenic acid, o-PhC(O)C6H4SeOH (1b).The probable reason for this large difference in rates is outlined.The difference in the rates of oxidation of 2 and 1b by MCPBA is much smaller, the selenenic acid being oxidized only 6 times faster than 2.Just as was found with selenenic acid 1a and its methyl ester, the rate of oxidation of sulfenic acid 2 by MCPBA is much faster than the rate of oxidation of its methyl ester.
Process for concentrating halogenoanthraquinones
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, (2008/06/13)
A process for concentrating at least one of (a) individual halogenoanthraquinones (b) binary mixtures of di-halogenoanthraquinones and (c) binary mixtures of trihalogenoanthraquinones, from a mixture containing at least two halogenoanthraquinones, comprising subjecting said mixture containing at least two halogenoanthraquinones to fractional vacuum distillation in a heated rectification column having an efficiency corresponding to about 20 to 50 theoretical stages with an absolute pressure at the top of about 0.5 to 50 mm Hg and a reflux to take-off ratio of about 5/1 to 50/1. Advantageously, distillation is carried out continuously in a cascade of columns, the products withdrawn from the top of the first column being 2-chloroanthraquinone in the first stage, 1-chloroanthraquinone in the second stage, 1,6- and 1,7-dichloroanthraquinone in the third stage and 1,5- and 1,8-dichloroanthraquinone in the fourth stage, 1,4,5- and 1,4,6-trichloroanthraquinone being obtained in the sump of the 4th stage and being separated therefrom by film evaporation. The mixture of halogenoanthraquinones is advantageously a mixture of chloroanthraquinones such as is obtained by the action of chlorine, chloric acid or a chlorate on various industrial mixtures of nitro- or sulfo-anthraquinones.