New Heteroaromatic Azo Compounds Based on Pyridine, Isoxazole, and Benzothiazole for Efficient and Highly Selective Amidation and Mono-<i>N</i>-Benzylation of Amines under Mitsunobu Conditions
4,4′-Azopyridine (2c) is used in conjunction with triphenylphosphine for the efficient conversion of carboxylic acids into amides via Mitsunobu reaction with primary and secondary aliphatic and aromatic amines. The highly selective amidation of only primary aromatic amines with new heterogeneous azo compounds based on benzothiazole 2d and isoxazole 2e is also described. These azo compounds 2c–2e can also be applied for selective mono-N-benzylation of primary aromatic amines. The solid side product heteroaromatic hydrazines obtained under the developed Mitsunobu conditions are easily separated by simple filtration and can be reoxidized to azo compounds for further use.
Photocatalysis Enabling Acceptorless Dehydrogenation of Diaryl Hydrazines at Room Temperature
作者:Manoj K. Sahoo、Krishnasamy Saravanakumar、Garima Jaiswal、Ekambaram Balaraman
DOI:10.1021/acscatal.8b01579
日期:2018.8.3
catalytic acceptorless dehydrogenation of diarylhydrazine derivatives to access a wide variety of aryl-azo compounds with the removal of molecular hydrogen as the sole byproduct. This distinctive reactivity has been achieved under dual catalytic conditions by merging the visible-light active [Ru(bpy)3]2+ as the photoredox catalyst and Co(dmgH)2(py)Cl as the proton-reduction catalyst. The reaction proceeds
Convenient semihydrogenation of azoarenes to hydrazoarenes using H<sub>2</sub>
作者:Manoj K. Sahoo、Ganesan Sivakumar、Sanjay Jadhav、Samrin Shaikh、Ekambaram Balaraman
DOI:10.1039/d1ob00850a
日期:——
The high atom-economical and eco-benign nature of hydrogenation reactions make them much more superior to conventional reduction and transferhydrogenation. Herein, a convenient and highly selective hydrogenation reaction of azoarenes using molecular hydrogen to access diverse hydrazoarenes is reported. The present catalytic method is general and operationally simple, and it operates under exceedingly
Additive-free aerobic oxidation of hydroazobenzenes: Access to azobenzenes and epoxidation of enones
作者:Yu Lin、Hao Wu、Ziang Liu、Jin Li、Rui Cai、Makoto Hashimoto、Lei Wang
DOI:10.1016/j.tetlet.2022.154132
日期:2022.10
to prepare azobenzenes from hydroazobenzenes via an additive-freeaerobicoxidation strategy. This method smoothly produces azobenzenes and heterocyclic azo derivatives in DMF at 80 °C under oxygen atmosphere. It features excellent yield, functional group tolerance and convenience. The broad application of this method is further proved by gram scale synthesis and the epoxidation of enones.
我们在此报道了一种通过无添加剂好氧氧化策略从氢偶氮苯制备偶氮苯的高效方法。该方法在氧气气氛下在 80 °C 下在 DMF 中顺利生成偶氮苯和杂环偶氮衍生物。它具有优异的产量、官能团耐受性和便利性。克级合成和烯酮的环氧化进一步证明了该方法的广泛应用。