92533-24-9Relevant academic research and scientific papers
Direct arylation of oxazole and benzoxazole with aryl or heteroaryl halides using a palladium-diphosphine catalyst
Derridj, Fazia,Djebbar, Safia,Benali-Baitich, Ouassini,Doucet, Henri
, p. 135 - 144 (2008/03/30)
Through the use of PdCl(dppb)(C3H5) as a catalyst, a range of aryl bromides and chlorides undergoes coupling via C-H bond activation/functionalization reaction with oxazole or benzoxazole in good yields. This air-stable catalyst can be used at low loadings with several substrates. Surprisingly, better results in terms of substrate/catalyst ratio were obtained in several cases using electron-excessive aryl bromides than with the electron-deficient ones. This seems to be mainly due to the relatively low thermal stability of some of the 2-arylbenzoxazoles formed with electron-deficient aryl halides. With these substrates, in order to obtain higher yields of product, the reactions had to be performed at a lower temperature (100-120 °C) using a larger amount of catalyst. On the other hand, in the presence of the most stable products, the reactions were performed at 150 °C using as little as 0.2 mol% catalyst. Arylation of benzoxazole with heteroaryl bromides also gave the coupling products in moderate to high yields using 0.2-5 mol% catalyst. With this catalyst, electron-deficient aryl chloride such as 4-chlorobenzonitrile, 4-chloroacetophenone or 2-chloronitrobenzene have also been used successfully.
A Comparison of the Flash Vacuum Pyrolysis Products of Some N-Acylbenzotriazoles and N-Acylbenzisoxazolones
Baradarani, Mehdi M.,Khalafy, Jabbar,Prager, Rolf H.
, p. 775 - 780 (2007/10/03)
The flash vacuum pyrolysis (f.v.p.) products of 2-(1H-benzotriazol-1-ylcarbonyl)benzonitrile, methyl 2-(1H-benzotriazol-1-ylcarbonyl)benzoate and 1-(2-chloromethylbenzoyl)-1H-benzotriazole and the corresponding benzisoxazolones have been characterized. The benzotriazole derivatives gave compounds whose origin suggests the predominance of radical processes. At lower temperatures the benzisoxazolones gave benzoxazole products consistent with a singlet carbene intermediate, but which had triplet diradical properties at higher temperatures, leading to the formation of acridine from the chloromethyl compound. The major low-temperature f.v.p. product from the (chloromethylbenzoyl)benzisoxazolone was indolo[1,2-b]benzoxazole.
