- Liquid azo dyes
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Any liquid azo dyes, in which auxochrome such as dialkylamino, alkoxy, and amino group is attached in a molecule, were produced. In a series of 2-alkyl-4'-(dimethylamino)azobenzenes, the butyl, hexyl, octyl, and dodecyl derivatives were liquid at room temperature, whereas the propyl, 1-methylethyl, 1-methylpropyl, 1,1-dimethylethyl, and octadecyl derivatives were solid. Thus, it is essential for liquid azo dyes to have a medium n-alkyl group at the 2-position. In a series of 2-butyl-4'-(dialkylamino)azobenzenes, the dimethylamino, diethylamino, dibutylamino, dioctylamino, and didodecylamino derivatives were liquid. 2-Butyl-4'-methoxyazobenzene and 4-amino-3,5-dimethyl-2'-butylazobenenzne were also liquid, whereas 2-butyl-4'-hydroxyazobenznene, 4-amino-2'-butylazobenzene, and 2-butyl-4'-(methylamino)azobenzene were solid. The prevention of π/π stacking, alkyl-alkyl interactions, and intermolecular hydrogen bond could produce liquid azo dyes.
- Biradar, Siddanagouda,Kasugai, Ryohei,Kanoh, Hisayoshi,Nagao, Hitoshi,Kubota, Yasuhiro,Funabiki, Kazumasa,Shiro, Motoo,Matsui, Masaki
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- Nitrosation of arenes with nitrosonium ethyl sulfate
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Nitrosonium ethyl sulfate reacts with O-alkylphenols and N,N-dialkylanilines to give the corresponding 4-nitrosoarenes. The reaction is not accompanied by side processes characteristic of common nitrosating agents. Diazotization of primary aromatic amines with nitrosonium ethyl sulfate yields stable diazonium salts, which are promising reagents for organic synthesis.
- Zyk,Nesterov,Khlobystov,Zefirov
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p. 506 - 509
(2007/10/03)
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- Possibility of the Intarmolecularity of Triazene Rearrangement
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The mechanism for the ortho-rearrangement of diaryltriazenes still remains equivocal.An interesting result suggesting an intramolecular nature of the triazene rearrangement was obtained on the basis of the effect of concentration of added N,N-dimethylaniline in the ortho-rearrangement of 1,3-bis(4-methylphenyl)triazene (1).The ortho/para ratio for the rearrangement of 1,3-diphenyltriazene (4) tends to increase with an increase of the viscosity.The results are discussed on the basis of increasing nucleophilicity of free amine by H-bonding with dimethylaniline and favoring ortho-migratrion with viscosity, respectively.
- Ogata, Yoshiro,Nakagawa, Yoshiaki,Inaishi, Morio
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p. 2853 - 2854
(2007/10/02)
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