136540-09-5Relevant articles and documents
Unexpected dealkylation during nucleophilic substitution: Synthesis of 2-N,N-dialkylamino benzoxazoles and benzothiazoles
Khalaf, Abedawn I,Alvarez, Ricardo G,Suckling, Colin J,Waigh, Roger D
, p. 8567 - 8571 (2000)
Mild reaction conditions are described for the preparation of a number of 2-alkyl- and 2-arylaminobenzoxazoles and benzothiazoles from 2-chlorobenzoxazole and 2-chlorobenzothiazole and N-methyl or other simple N-alkyl tertiary amines. The reaction proceeds neat or in THF solution and involves dealkylation of the amine reactant by nucleophilic substitution by chloride. In the case of N-methylpyrrolidine and N-methylpiperidine demethylation was not observed and the major product was formed by ring opening to give chlorobutyl- and chloropentyl-methylamino substituted benzoxazoles and benzothiazoles. Treatment of the chlorobutyl derivative with iodide in acetone afforded the new 1H,2H,3H,4H,5H-[1,3]diazepino[2,1-b][1,3]benzoxazol-6-ium ring system. (C) 2000 Elsevier Science Ltd.
Buchwald-Hartwig Amination of Coordinating Heterocycles Enabled by Large-but-Flexible Pd-BIAN-NHC Catalysts**
Li, Dong-Hui,Lan, Xiao-Bing,Song, A-Xiang,Rahman, Md. Mahbubur,Xu, Chang,Huang, Fei-Dong,Szostak, Roman,Szostak, Michal,Liu, Feng-Shou
supporting information, (2021/12/06)
A new class of large-but-flexible Pd-BIAN-NHC catalysts (BIAN=acenaphthoimidazolylidene, NHC=N-heterocyclic carbene) has been rationally designed to enable the challenging Buchwald-Hartwig amination of coordinating heterocycles. This robust class of BIAN-NHC catalysts permits cross-coupling under practical aerobic conditions of a variety of heterocycles with aryl, alkyl, and heteroarylamines, including historically challenging oxazoles and thiazoles as well as electron-deficient heterocycles containing multiple heteroatoms with BIAN-INon (N,N′-bis(2,6-di(4-heptyl)phenyl)-7H-acenaphtho[1,2-d]imidazol-8-ylidene) as the most effective ligand. Studies on the ligand structure and electronic properties of the carbene center are reported. The study should facilitate the discovery of even more active catalyst systems based on the unique BIAN-NHC scaffold.
Copper-catalyzed oxidative C-H, N-H coupling of azoles and thiophenes
Mitsuda, Shinobu,Fujiwara, Taiki,Kimigafukuro, Katsuyoshi,Monguchi, Daiki,Mori, Atsunori
experimental part, p. 3585 - 3590 (2012/06/30)
CH, NH coupling of azole and thiophene derivatives takes place in the presence of a catalytic amount of Cu(OAc)2 and an additive. The reaction of azoles smoothly occurs with several amines and amides catalyzed by 20 mol % of Cu(OAc)2-2PPh3 and 4 equiv of NaOAc under O2 or in the presence of Ag2CO3 under N 2. The coupling reaction leads to a facile synthesis of a N-substituted analogue of 2,5-diarylthiazole, which shows photoluminescent properties with extended π-conjugation. Spectroscopic characteristics of the obtained thiazole derivatives are discussed by measurements of UV-vis absorption and photoluminescent spectra. Under the reaction conditions using Ag 2CO3 as an additive and Cu(OAc)2-2PPh 3 as a catalyst, thiophene derivatives also react with 2-pyrrolidone to undergo CH, NH amidation.
