Iron(0)-Catalyzed Transfer Hydrogenative Condensation of Nitroarenes with Alcohols: A Straightforward Approach to Benzoxazoles, Benzothiazoles, and Benzimidazoles
作者:Ramachandra Reddy Putta、Simin Chun、Seung Hyun Choi、Seok Beom Lee、Dong-Chan Oh、Suckchang Hong
DOI:10.1021/acs.joc.0c02191
日期:2020.12.4
the redox condensation of o-hydroxynitrobenzene with alcohol, leading to the formation of benzoxazole derivatives. A wide range of 2-substituted benzoxazoles were synthesized in good to excellent yields without the addition of an external redox agent. A series of control experiments provided a plausible mechanism. Furthermore, the reaction system was successfully extended to the synthesis of benzothiazoles
Lawesson'sreagent acts as an efficient promoter in the solvent-free microwave-assisted synthesis of 2-substituted benzoxazoles from carboxylic acids and 2-aminophenol, and thus, constitutes a general synthetic method for these compounds. This new application of Lawesson'sreagent is valid also for benzothiazoles with very high efficiency level. A variety of aromatic, heteroaromatic and aliphatic carboxylic
A synthesis of 2-substituted oxazolo[3,2-a]pyridiniumsalts is described. The appropriate 2-(4-ethoxybutyryl)-oxazoles are treated with hydrobromic acid and then cyclised and aromatised by boiling acetic anhydride. Attempts to prepare 2-substituted oxazoles suitable for the synthesis of the parent oxazolopyridinium ion have been unsuccessful. Catalytic reduction of two oxazolopyridinium salts leads
描述了2-取代的恶唑并[3,2- a ]吡啶鎓盐的合成。用氢溴酸处理适当的2-(4-乙氧基丁酰基)-恶唑,然后环化并通过沸腾乙酸酐使其芳香化。尝试制备适合于母体恶唑吡啶鎓离子合成的2-取代的恶唑是失败的。两种恶唑并吡啶鎓盐的催化还原导致开环,得到N-取代的2-哌啶酮。
Nickel(II)-Catalyzed Addition of Aryl-, Alkenyl-, and Alkylboronic Acids to Alkenylazaarenes
作者:Xing-Yu Liu、Yun-Xuan Tan、Xin Wang、Hao Xu、Yu-Hui Wang、Ping Tian、Guo-Qiang Lin
DOI:10.1021/acs.orglett.0c01425
日期:2020.5.15
A nickel(II)-catalyzedaddition of aryl-, alkenyl-, and alkylboronic acids to alkenylazaarenes was presented. This reaction exhibited high efficiency (up to 93% yield), a broad substrate scope (seven types of heterocycles), and good functional group compatibility. The resulting products can be further transformed to many useful building blocks. Finally, the preliminary studies suggested that the adjacent