Palladium-Catalyzed Synthesis of 2-Aryl-2H-Benzotriazoles from Azoarenes and TMSN3
摘要:
Substrate-directed ortho C-H amination of azoarenes using TMSN3 as the source of nitrogen leading to the synthesis of 2-aryl-2H-benzotriazoles has been accomplished with the help of Pd/TBHP combinations. An intermolecular o-azidation (C-N bond formation) followed by an intramolecular N-N bond formation via nucleophilic attack of one of the azo nitrogen onto the o-azide nitrogen leads to cyclization with the expulsion of N-2.
The Wallach Rearrangement of Some 4,4′-Disubstituted Azoxybenzenes
作者:Ichiro Shimao、Shigeru Oae
DOI:10.1246/bcsj.56.643
日期:1983.2
treatment of azoxybenzenes bearing electron-withdrawing substituents at 4,4′-positions with sulfuric acid gave the corresponding 2-hydroxyazobenzenes, together with 4′-substituted 4-hydroxyazobenzenes. The treatment of 4,4′-dimethoxyazoxybenzene with p-toluenesulfonic acid and acetic anhydride afforded 4,4′-dimethoxy-3-acetoxyazobenzene and 4,4′-dimethoxy-2-tosyloxyazobenzene as the main rearrangement products
Palladium-Catalyzed Synthesis of 2-Aryl-<i>2H</i>-Benzotriazoles from Azoarenes and TMSN<sub>3</sub>
作者:Nilufa Khatun、Anju Modi、Wajid Ali、Bhisma K. Patel
DOI:10.1021/acs.joc.5b01706
日期:2015.10.2
Substrate-directed ortho C-H amination of azoarenes using TMSN3 as the source of nitrogen leading to the synthesis of 2-aryl-2H-benzotriazoles has been accomplished with the help of Pd/TBHP combinations. An intermolecular o-azidation (C-N bond formation) followed by an intramolecular N-N bond formation via nucleophilic attack of one of the azo nitrogen onto the o-azide nitrogen leads to cyclization with the expulsion of N-2.
Twin liquid crystals and segmented thermotropic polyesters containing azobenzene—effect of spacer length on LC properties
作者:Chinmay G. Nardele、S. K. Asha
DOI:10.1002/pola.26062
日期:2012.7.15
series of twinliquid crystalline (LC) molecules based on phenyl and naphthyl azobenzene (PnP and NpnNp) as well as segmented copolyesters based on them. The twin series had the structure azobenzene–oligooxyethylene–azobenzene, where the ethyleneoxy length was varied from 2 to 6 units. The LCproperties of the twin series depended on the chemical structure of the azochromophore and also the length of the