Convenient One-Pot Synthesis of 2,5-Disubstituted Oxazoles via a Catalytic Oxidative Dehydrogenation of F<sub>3</sub>CSO<sub>3</sub>H·SiO<sub>2</sub>-DDQ/CuCl<sub>2</sub>/LiCl
作者:Shizhen Yuan、Zhen Li、Ling Xu
DOI:10.1002/jhet.1637
日期:2013.11
A facile one‐potsynthesis of 2,5‐disubstitutedoxazoles was developed via cyclization of aldoximes and phenylacetylene then dehydrogenation oxidation. 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone was studied for the selective oxidation of oxazolines using Cu2+/Li+ as catalyst and O2 as indirect oxidant. The reaction results showed that this catalyst system can effectively catalyze the oxidation of oxazolines
通过醛肟和苯乙炔的环化然后脱氢氧化制得了一种简便的一锅合成2,5-二取代的恶唑。以Cu 2+ / Li +为催化剂,O 2为间接氧化剂,研究了2,3-二氯-5,6-二氰基-1,4-苯醌对氧化唑啉的选择性氧化。反应结果表明,该催化剂体系可有效催化恶唑啉氧化为相应的恶唑。因此,通过2,3-二氯-5,6-二氰基-1,4-苯醌/ CuCl 2 / LiCl / O 2的催化氧化,很容易以高收率合成各种多取代的恶唑。
CO<sub>2</sub>/Photoredox-Cocatalyzed Tandem Oxidative Cyclization of α-Bromo Ketones and Amines To Construct Substituted Oxazoles
作者:Xiaowei Zhang、Yonghui He、Jing Li、Rui Wang、Lijun Gu、Ganpeng Li
DOI:10.1021/acs.joc.9b00283
日期:2019.6.21
CO2/photoredox-cocatalyzed tandem oxidative cyclization of α-bromo ketones and amines for the preparation of substituted oxazoles has been achieved. The avoidance of using both transition-metal catalysts and peroxides makes this method more sustainable and renewable.
Spectral and time-resolved fluorescence properties as well as relative fluorescence quantum yields of carbodiimide derivatives of 2.5-diphenyloxazole (PPO) (prepared by H2S elimination from the corresponding thioureas), of some intermediates in the preparation, and of several other PPO derivatives were investigated in solution and in the solid state to test their suitability as solid scintillators
Photoinduced Copper-Catalyzed C−H Arylation at Room Temperature
作者:Fanzhi Yang、Julian Koeller、Lutz Ackermann
DOI:10.1002/anie.201512027
日期:2016.4.4
Room‐temperature azole C−H arylations were accomplished with inexpensive copper(I) compounds by means of photoinduced catalysis. The expedient copper catalysis set the stage for site‐selective C−H arylations of non‐aromatic oxazolines under mild reaction conditions, and provides step‐economical access to the alkaloid natural products balsoxin and texamine.
An efficient synthesis of 2,5-disubstitutedoxazolesvia Co(III) catalysis is described herein. The synthesis is achieved under mild conditions through [3+2] cycloaddition of N-pivaloyloxyamides and alkynes. The reaction operates through an internal oxidation pathway and features a very broad substrate scope. The one-step synthesis of natural products such as texamine and balsoxin has been demonstrated