2851-09-4Relevant articles and documents
New topological Co2(BDC)2(DABCO) as a highly active heterogeneous catalyst for the amination of oxazoles via oxidative C-H/N-H couplings
Tu, Thach N.,Nguyen, Khoa D.,Nguyen, Truong N.,Truong, Thanh,Phan, Nam T. S.
, p. 1384 - 1392 (2016)
Herein, we report the synthesis, structural characterization, and catalytic properties of a new cobalt-based metal-organic framework, Co2(BDC)2(DABCO) (where BDC = 1,4-benzenedicarboxylate and DABCO = 1,4-diazabicyclo[2.2.2]octane), namely VNU-10 (where VNU = Vietnam National University). Single-crystal X-ray diffraction analysis revealed that VNU-10 crystallizes in the hexagonal space group P6/mmm. The structure of this material is comprised of two-dimensional kgm layers which are interconnected by DABCO pillars to afford an overall three-dimensional porous architecture. VNU-10 exhibited exceptional catalytic activity toward the direct amination of oxazoles via C-H/N-H couplings while a previously reported topological isomer, Co2(BDC)2(DABCO), with the sql topology, displayed poor activity. Leaching tests indicated that homogeneous catalysis via leached active cobalt species is unlikely. Furthermore, the VNU-10 catalyst was facilely isolated from the reaction mixture and reused several times without degradation of the catalytic reactivity.
Room-Temperature Amination of Chloroheteroarenes in Water by a Recyclable Copper(II)-Phosphaadamantanium Sulfonate System
Dandela, Rambabu,Desai, Aman A.,Kapdi, Anant R.,Kori, Santosh,Maity, Dilip K.,Parmar, Udaysinh,Somvanshi, Dipesh
, p. 8900 - 8925 (2021/07/20)
Buchwald-Hartwig amination of chloroheteroarenes has been a challenging synthetic process, with very few protocols promoting this important transformation at ambient temperature. The current report discusses about an efficient copper-based catalytic system (Cu/PTABS) for the amination of chloroheteroarenes at ambient temperature in water as the sole reaction solvent, a combination that is first to be reported. A wide variety of chloroheteroarenes could be coupled efficiently with primary and secondary amines as well as selected amino acid esters under mild reaction conditions. Catalytic efficiency of the developed protocol also promotes late-stage functionalization of active pharmaceutical ingredients (APIs) such as antibiotics (floxacins) and anticancer drugs. The catalytic system also performs efficiently at a very low concentration of 0.0001 mol % (TON = 980,000) and can be recycled 12 times without any appreciable loss in activity. Theoretical calculations reveal that the π-acceptor ability of the ligand PTABS is the main reason for the appreciably high reactivity of the catalytic system. Preliminary characterization of the catalytic species in the reaction was carried out using UV-VIS and ESR spectroscopy, providing evidence for the Cu(II) oxidation state.
Zwitterionic Ring-Opened Oxyphosphonium Species from the Ph3P-I2 Mediated Reactions of Benzo[ d]oxazol-2(3 H)-ones with Secondary Amines
Pattarawarapan, Mookda,Wiriya, Nittaya,Yimklan, Saranphong,Wangngae, Sirilak,Phakhodee, Wong
, p. 6151 - 6158 (2020/05/20)
Instead of the expected substituted 2-aminobenzo[d]oxazoles, relatively stable ring-opened oxyphosphonium betaines were isolated for the first time from the Ph3P-I2-mediated reactions of benzo[d]oxazol-2(3H)-ones with acyclic seconda
