20055-04-3Relevant academic research and scientific papers
2,3-disubstituted pyrrole or 2,3,4-trisubstituted pyrrole prepared by one-pot method and preparation method thereof
-
Paragraph 0157-0162, (2019/10/08)
The invention provides 2,3-disubstituted pyrrole or 2,3,4-trisubstituted pyrrole prepared by a one-pot method and a preparation method thereof. Ketoxime and p-toluenesulfonyl chloride generate ketoxime sulfonate under alkaline conditions, the ketoxime sulfonate is not separated, Neber rearrangement is carried out under the conditions to obtain a nitrogen heterocyclic propylene intermediate, and the nitrogen heterocyclic propylene intermediate and proton-containing ketone at an alpha position are subjected to ring opening and cyclization to obtain the 2,3-disubstituted pyrrole or 2,3,4-trisubstituted pyrrole. The invention firstly provides the method for preparing the 2,3-disubstituted pyrrole or 2,3,4-trisubstituted pyrrole through the steps that the ketoxime and p-toluenesulfonyl chloride generate the ketoxime sulfonate under the alkaline conditions, the ketoxime sulfonate is not separated, and the intermediate obtained by the Neber rearrangement under the conditions and the ketone are subjected to the ring opening and cyclization, the synthesis step is simplified, the yield is improved, and the range of application of the reaction is expanded.
General Transition Metal-Free Synthesis of NH-Pyrroles from Secondary Alcohols and 2-Aminoalcohols
Krasniqi, Besir,Geerts, Kayle,Dehaen, Wim
, p. 5027 - 5034 (2019/05/10)
A novel, transition metal-free and one-pot methodology to synthesize various substituted NH-pyrroles from readily available building blocks such as secondary alcohols and 2-aminoalcohols is described. The process is based on the venerable Oppenauer-Woodward oxidation, which uses benzophenone as an inexpensive reagent to achieve oxidation of secondary alcohols under mild condition to ketones, further in situ condensation with aminoalcohol, and oxidative cyclization to the target pyrrole ring. The reaction occurs under basic conditions, and features a broad substrate scope combined with very good tolerance for sensitive functional groups. This method can be used to synthesize various substituted pyrroles useful as a starting material for broad applications.
Pd(II)/Bu4NBr/DMSO catalytic system for practical synthesis of indoles and pyrroles from imines through aerobic dehydrogenative cyclization
Tan, Wei Wen,Hou, Xiaoya,Yoshikai, Naohiko
, p. 2727 - 2733 (2015/05/05)
N-Aryl- and N-allylimines derived typically from substituted acetophenones undergo palladium(II)-catalyzed dehydrogenative cyclization reactions in the presence of tetrabutylammonium bromide and molecular oxygen in DMSO to afford indole and pyrrole deriva
Copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates: A facile synthesis of 2-arylpyrroles
Du, Wei,Zhao, Mi-Na,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
supporting information, p. 7437 - 7439 (2014/07/07)
A novel and facile copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates for the synthesis of 2-arylpyrroles has been developed. The reaction tolerates a range of functional groups and is a practical procedure for rapid synthesis of 2-arylpyrroles in high yields under mild conditions. the Partner Organisations 2014.
α-Palladation of imines as entry to dehydrogenative heck reaction: Aerobic oxidative cyclization of N-allylimines to pyrroles
Chen, Zhiyuan,Lu, Beili,Ding, Zhenhua,Gao, Ke,Yoshikai, Naohiko
supporting information, p. 1966 - 1969 (2013/06/04)
We report here a palladium(II)-catalyzed oxidative cyclization reaction of N-allylimines derived from methyl ketones, typically acetophenones, affording pyrrole derivatives at room temperature under oxygen atmosphere. The reaction likely proceeds through α-palladation of the imine followed by olefin migratory insertion and β-hydride elimination, thus representing a new example of aerobic dehydrogenative Heck cyclization.
Palladium-catalysed aerobic oxidative Heck-type alkenylation of Csp 3-H for pyrrole synthesis
Meng, Lingkui,Wu, Kun,Liu, Chao,Lei, Aiwen
supporting information, p. 5853 - 5855 (2013/07/19)
The first palladium-catalysed aerobic oxidative intramolecular alkenylation of Csp3-H bonds was described. The reaction conditions were mild and molecular oxygen was used as the terminal oxidant. Kinetic studies showed that the Csp3-H metallation step was a slow step.
Aerobic synthesis of pyrroles and dihydropyrroles from imines: Palladium(II)-catalyzed intramolecular C-H dehydrogenative cyclization
Shi, Zhuangzhi,Suri, Mamta,Glorius, Frank
, p. 4892 - 4896 (2013/06/04)
sp3ectacularly mild! An efficient PdII-catalyzed intramolecular dehydrogenative cyclization of imines affords (dihydro)pyrrole products using molecular oxygen as the sole oxidant. This mild formal sp 3-C-H functionalization allows rapid and atom-economical assembly of (dihydro)pyrrole rings from inexpensive and readily available allylamines and ketones. A broad range of functional groups are tolerated. Copyright
A simple and efficient protocol to 1,2,4-substituted pyrroles via a sonogashira coupling-acid-catalyzed cyclization
Zhu, Da,Zhao, Jie,Wei, Yuxiu,Zhou, Hongwei
supporting information; experimental part, p. 2185 - 2186 (2011/10/09)
A facile and efficient protocol for the synthesis of 1,2,4-substituted pyrrole derivatives was developed. As a result of the ready availability of materials and the simple operation, this type of reaction should have potential utility in organic synthesis. Georg Thieme Verlag Stuttgart · New York.
Carbon-carbon bond formation and pyrrole synthesis via the [3,3] sigmatropic rearrangement of O-vinyl oxime ethers
Wang, Heng-Yen,Mueller, Daniel S.,Sachwani, Rachna M.,Londino, Hannah N.,Anderson, Laura L.
supporting information; experimental part, p. 2290 - 2293 (2010/08/05)
A new method for the synthesis of 2,4- and 2,3,4-substituted pyrroles in two or three steps from commercially available ketones and allyl hydroxylamine is described. An iridium-catalyzed isomerization reaction has been developed to convert O-allyl oximes
New efficient, flexible and regioselective synthesis of 2,4-Di- and 2,3,4-trialkylated and arylated 1H-pyrroles
Enders, Dieter,Maassen, Ralf,Han, Sin-Ho
, p. 1565 - 1574 (2007/10/03)
Starting from easily available 2-acetoxy aldehyde dimethylhydrazones rac-2, we prepared various alkyl- and aryl-substituted 1H-pyrroles 6 in good overall yield. The titanium-mediated a2-umpolung reaction of rac-2 with different acyclic and cyclic silyl enol ethers 3 leads directly or via 4-oxo hydrazones rac,anti-4 to 1-(dimethylamino)-1H-pyrroles 5. A novel method for the reductive removal of the dimethylamino group affording 1H-pyrroles 6 is presented. VCH Verlagsgesellschaft mbH, 1996.
