A Convenient Synthesis of 2-Oxazolines and 2-Benoxazoles with PPh3-DDQ as the Dehydrating Reagent
作者:Quancai Xu、Zhengning Li、Huiying Chen
DOI:10.1002/cjoc.201190190
日期:2011.5
2‐benoxazoles were synthesized in high yields from acylamino alcohols and acylamino‐ phenols, respectively, with triphenylphosphine‐2,3‐dichloro‐5,6‐dicyanobenzoquinone (PPh3‐DDQ) as the dehydrating and activating reagent. The synthesis was accomplished under neutral conditions.
Iron(III) Chloride Mediated
<i>para</i>
‐Selective C‐H Functionalization: Access to C5‐Chloro and C5,C7‐Dichloro/Dianisyl Substituted 2‐Arylbenzoxazoles
作者:Kanchanbala Sahoo、Niranjan Panda
DOI:10.1002/adsc.202101359
日期:2022.3
Iron(III) chloride mediated para-selective C−H chlorination and subsequent annulation of 2-amidophenol to synthesize C5- and C5, C7-chlorinated benzoxazoles was developed. Further, the oxidative cross-dehydrogenative coupling of amidophenol with anisole by ferricchloride was explored to achieve the remotely anisylated benzoxazoles.
Tertiary Amine-Catalyzed Acyl Group Exchange Reaction of<i>N</i>,<i>O</i>-Diacyl-<i>o</i>-aminophenols. Its Mechanism and Factors Determining the Relative Stability of Acyl Exchanged Isomer Pairs
polarities. It was found that the relativestability of acyl exchanged isomer pairs is determined solely by the inductive effect of acyl groups, provided that the steric hindrance of acyl substituents bonded to amide nitrogen affects the stability to the same extent. The importance of steric hindrance exerted by a bulky acyl group in determining the relativestability was demonstrated by analyzing the
A kinetic study on the base-catalyzed acyl group-exchange reactions of N,O-diacyl-o-aminophenols was undertaken to show that the formation of the amidate ion should be the rate-determining step in these intramolecular acyl-exchange reactions, and that the electron-withdrawing power of acyl group becomes an important factor to control the relative stabilities of a pair of N,O-diacyl-o-aminophenols.
The photochemical decomposition of the title compounds yielded the rearrangement products derived from 1,3- and 1,5-aroyloxyl migrations in addition to the fragmentation products typical of the aroyloxyl and amido radicals, while only 1,3-aroyloxyl migration was observed on thermolysis. The results of crossover experiments indicate an intramolecular rearrangement, probably involving homolysis of the