3274-32-6Relevant academic research and scientific papers
Palladium-catalyzed selective formation of substituted pyrroles from alkene-tethered cyclic oxime esters
Okamoto, Kazuhiro,Oda, Tomohiro,Matsushita, Gaku,Shimbayashi, Takuya,Sasakura, Kohei,Ohe, Kouichi
, p. 218 - 231 (2019/04/27)
Isoxazol-5(4H)-ones were used as nitrene precursors for the selective formation of trisubstituted pyrroles by applying a palladium-catalyzed decarboxylative ring-reconstruction method. The use of bulky biaryl-type monophosphine ligands was effective for improving the selectivity. Deuterium-labeling experiments suggested a mechanism involving β-hydride elimination followed by reductive elimination from an aza-π-allyl intermediate.
Preparation method of derivatives of pyrrole, imidazole, and oxazole
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Paragraph 0014; 0015; 0018, (2017/07/19)
The invention relates to a preparation method of derivatives of pyrrole, imidazole, and oxazole. Specifically, in the presence of triphenyl phosphine, various alkenyl azides carry out cyclization reactions to generate derivatives of pyrrole, imidazole, an
Method of manufacturing pyrrolecarboxylic
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Paragraph 0048-0054; 0055-0057, (2016/11/09)
PROBLEM TO BE SOLVED: To provide a method obtainable of a pyrrole in a good yield. SOLUTION: As shown by chemical reaction formula (1) and chemical reaction formula (2), a β-amino alcohol is reacted with a carbonyl compound or an alcohol in the pres
Insertion of Nitriles into Zirconocene 1-aza-1,3-diene Complexes: Chemoselective Synthesis of N-H and N-Substituted Pyrroles
Yu, Shasha,Xiong, Meijun,Xie, Xin,Liu, Yuanhong
supporting information, p. 11596 - 11599 (2016/02/19)
The direct insertion of nitriles into zirconocene-1-aza-1,3-diene complexes provides an efficient, chemoselective, and controllable synthesis of N-H and N-substituted pyrroles upon acidic aqueous work-up. The outcome of the reaction (that is, the formatio
The dual role of ruthenium and alkali base catalysts in enabling a conceptually new shortcut to N-unsubstituted pyrroles through unmasked α-amino aldehydes
Iida, Kazuki,Miura, Takashi,Ando, Junki,Saito, Susumu
supporting information, p. 1436 - 1439 (2013/06/26)
A virtually salt-free and straightforward bimolecular assembly giving N-unsubstituted pyrroles through fully unmasked α-amino aldehydes, which was enabled by the dual effects of a catalytic ruthenium complex and an alkali metal base, is reported. Either solvent-free or acceptorless dehydrogenation facilitates high atom, step, and pot economy, which are otherwise difficult to achieve in multistep operations involving protection/deprotection.
Regioselective synthesis of 2,3,4- or 2,3,5-trisubstituted pyrroles via [3,3] or [1,3] rearrangements of O-vinyl oximes
Wang, Heng-Yen,Mueller, Daniel S.,Sachwani, Rachna M.,Kapadia, Rachel,Londino, Hannah N.,Anderson, Laura L.
supporting information; experimental part, p. 3203 - 3221 (2011/06/24)
The regioselective synthesis of 2,3,4- or 2,3,5-trisubstituted pyrroles has been achieved via [3,3] and [1,3] sigmatropic rearrangements of O-vinyl oximes, respectively. Iridium-catalyzed isomerization of easily prepared O-allyl oximes enables rapid access to O-vinyl oximes. The regioselectivity of pyrrole formation can be controlled by either the identity of the α-substituent or through the addition of an amine base. When enolization is favored, a [3,3] rearrangement followed by a Paal-Knorr cyclization provides a 2,3,4-trisubstituted pyrrole; when enolization is disfavored, a [1,3] rearrangement occurs prior to enolization to produce a 2,3,5-trisubstituted pyrrole after cyclization. Optimization and scope of the O-allyl oxime isomerization and subsequent pyrrole formation are discussed and mechanistic pathways are proposed. Conditions are provided for selecting either the [3,3] rearrangement or the [1,3] rearrangement product with β-ester O-allyl oxime substrates.
Photochemistry of N-heterocycles. 7: Light induced reductive ring contractions of sixmembered cyclic iminium ions
Nagy, Jozsef,Madarasz, Zoltan,Rapp, Rudolf,Szoelloesy, Aron,Nyitrai, Jozsef,Doepp, Dietrich
, p. 281 - 290 (2007/10/03)
Photochemically induced reductive ring contractions, previously observed for 2,5-dihydro-1,2,4-triazines, have also been verified for 1,4-dihydropyrimidines 2a,b, the dihydro-1,2,4,5-tetrazine 9, and dihydro-1,3,5-triazines 11a,b giving rise to fivemembered fully unsaturated heterocycles (pyrroles 4a,b, imidazoles 13a,b, and triazole 10, respectively). The 1,4-dihydropyrazines 15a-j tend to decompose in acidified 2-propanol in the dark, but on irradiation they also undergo reductive ring contraction furnishing solely the 1,2,5-triarylpyrroles 16a-d rather than the (a priori also possible) isomeric 1,3,4-triarylpyrroles 17a-d. In contrast, the 3,6-diphenylpyrid-azine 18 gives the 4-isopropyl-analogue 19 in low yield upon irradiation in hydrogen chloride saturated 2-propanol. Wiley-VCH Verlag GmbH, 2000.
Intermolecular Reductive Cross Coupling of Carbonyl Compounds with Nitriles Induced by Low-valent Titanium
Gao, Ju,Hu, Ming-yang,Chen, Jian-xie,Yuan, Su,Chen, Wei-xing
, p. 1617 - 1620 (2007/10/02)
Intermolecular cross coupling of carbonyl compounds with nitriles promoted by TiCl4-Zn leads to ketones.
