2467-83-6Relevant academic research and scientific papers
Biphilic Organophosphorus-Catalyzed Intramolecular Csp2-H Amination: Evidence for a Nitrenoid in Catalytic Cadogan Cyclizations
Nykaza, Trevor V.,Ramirez, Antonio,Harrison, Tyler S.,Luzung, Michael R.,Radosevich, Alexander T.
, p. 3103 - 3113 (2018/03/08)
A small-ring phosphacycloalkane (1,2,2,3,4,4-hexamethylphosphetane, 3) catalyzes intramolecular C-N bond forming heterocyclization of o-nitrobiaryl and -styrenyl derivatives in the presence of a hydrosilane terminal reductant. The method provides scalable access to diverse carbazole and indole compounds under operationally trivial homogeneous organocatalytic conditions, as demonstrated by 17 examples conducted on 1 g scale. In situ NMR reaction monitoring studies support a mechanism involving catalytic PIII/PV=O cycling, where tricoordinate phosphorus compound 3 represents the catalytic resting state. For the catalytic conversion of o-nitrobiphenyl to carbazole, the kinetic reaction order was determined for phosphetane catalyst 3 (first order), substrate (first order), and phenylsilane (zeroth order). For differentially 5-substituted 2-nitrobiphenyls, the transformation is accelerated by electron-withdrawing substituents (Hammett factor ? = +1.5), consistent with the accrual of negative charge on the nitro substrate in the rate-determining step. DFT modeling of the turnover-limiting deoxygenation event implicates a rate-determining (3 + 1) cheletropic addition between the phosphetane catalyst 3 and 2-nitrobiphenyl substrate to form an unobserved pentacoordinate spiro-bicyclic dioxazaphosphetane, which decomposes via (2 + 2) cycloreversion giving 1 equiv of phosphetane P-oxide 3·[O] and 2-nitrosobiphenyl. Experimental and computational investigations into the C-N bond forming event suggest the involvement of an oxazaphosphirane (2 + 1) adduct between 3 and 2-nitrosobiphenyl, which evolves through loss of phosphetane P-oxide 3·[O] to give the observed carbazole product via C-H insertion in a nitrene-like fashion.
Rh(I)-catalyzed decarbonylation synthesis of carbazoles via C-N cleavage
Fan, Weizheng,Jiang, Shan,Feng, Bainian
, p. 4035 - 4038 (2015/06/02)
A one-pot Rh(I)-catalyzed synthesis of 9-H carbazoles via C-N bond cleavage by activation of aldehyde C-H bonds is reported. This protocol offers good yields and tolerates a broad range of functional groups. Based on the extensive control experiments, we propose a plausible decarbonylation mechanism.
Direct synthesis of N -H carbazoles via iridium(III)-catalyzed intramolecular C-H amination
Suzuki, Chiharu,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
, p. 1597 - 1600 (2015/03/30)
The iridium-catalyzed dehydrogenative cyclization of 2-aminobiphenyls proceeds smoothly in the presence of a copper cocatalyst under air as a terminal oxidant through intramolecular direct C-H amination to produce N-H carbazoles. A similar iridium/copper system can also catalyze the unprecedented dimerization reaction of 2-aminobiphenyl involving 2-fold C-H/N-H couplings.
"transition-metal-free" synthesis of carbazoles by photostimulated reactions of 2′-halo[1,1′-biphenyl]-2-amines
Guerra, Walter D.,Rossi, Roberto A.,Pierini, Adriana B.,Barolo, Silvia M.
, p. 928 - 941 (2015/01/30)
An efficient and simple protocol for the preparation of a series of 9H-carbazoles by photostimulated SRN1 substitution reactions is presented. Substituted 9H-carbazoles were synthesized in low to excellent yields (up to 96%) through an intramolecular C-N bond formation of 2′-halo[1,1′-biphenyl]-2-amines by the photoinitiated SRN1 mechanism under mild and "transition-metal-free" conditions. The biphenylamines used as substrates were obtained with isolated yields ranging from 21% to 84% by two approaches: (A) the cross-coupling Suzuki-Miyaura reaction and (B) the radical arylation of anilines. Some key aspects of the proposed mechanism were evaluated at the B3LYP/6-311+G? level.
Synthesis of carbazoles by copper-catalyzed intramolecular C-H/N-H coupling
Takamatsu, Kazutaka,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
, p. 2892 - 2895 (2014/06/23)
A Cu-catalyzed intramolecular C-H amination for the synthesis of carbazoles has been developed. The key to success is the installation of the picolinamide-based directing group, which is spontaneously removed after the coupling event. The Cu catalysis proceeded smoothly under Pd- and I(III)-free conditions, and its mild oxidation aptitude enables the rapid and concise construction of heteroatom-incorporated carbazole core π-systems.
Amino-directed RhIII-catalyzed C-H activation leading to one-pot synthesis of N-H carbazoles
Jiang, Qibai,Duan-Mu, Dandan,Zhong, Wei,Chen, Hao,Yan, Hong
supporting information, p. 1903 - 1907 (2013/03/28)
One-pot synthesis: An efficient amino-directed one-pot synthesis of N-H carbazoles from unprotected 2-aminobiaryl compounds is reported. The free amino unit acts as both a directing group for ortho C-H activation and a functional group for construction of an N-heterocyclic ring (see scheme). Copyright
Kinesin spindle protein (KSP) inhibitors with 2,3-fused indole scaffolds
Oishi, Shinya,Watanabe, Toshiaki,Sawada, Jun-Ichi,Asai, Akira,Ohno, Hiroaki,Fujii, Nobutaka
experimental part, p. 5054 - 5058 (2010/09/05)
Mitotic kinesin spindle protein (KSP) is involved in the assembly of the bipolar spindle during cell division. On the basis of a common 2,3-fused indole substructure within the complex frameworks of terpendole E and other KSP inhibitors, the carbazoles with a bulky alkyl group were identified as a novel KSP inhibitory scaffold. Additionally, among several naturally occurring cell growth inhibitors with 2,3-fused indole structures,β-carboline alkaloids, harman and harmine, showed moderate inhibition of KSP.
Palladium-catalyzed direct synthesis of carbazoles via one-pot N-arylation and oxidative biaryl coupling: Synthesis and mechanistic study
Watanabe, Toshiaki,Oishi, Shinya,Fujii, Nobutaka,Ohno, Hiroaki
experimental part, p. 4720 - 4726 (2009/10/02)
(Chemical Equation Presented) An efficient catalytic system has been developed for the synthesis of carbazoles by one-pot N-arylation and oxidative biaryl coupling. A significant substituent effect of the diarylamine intermediate on oxidative coupling was observed. Mechanistic studies of oxidative coupling, including trapping of reaction intermediates and kinetic isotope effect experiments, are also presented.
Methods and compositions
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Page/Page column 14, (2009/07/17)
Compounds, compositions and methods relating to kinesin inhibition are described herein.
Rh2(II)-catalyzed synthesis of carbazoles from biaryl azides
Stokes, Benjamin J.,Jovanovic, Brankica,Dong, Huijun,Richert, Kathleen J.,Riell, Ryan D.,Driver, Tom G.
supporting information; experimental part, p. 3225 - 3228 (2009/08/07)
An array of carbazoles (23 examples) can be synthesized from substituted biaryl azides at 60 °C using substoichio-metric quantities of Rh 2(O2CC3F7)4 or Rh 2(O2CC7H15)4.
