80224-46-0Relevant academic research and scientific papers
IBX-Promoted Oxidative Cyclization of N-Hydroxyalkyl Enamines: A Metal-Free Approach toward 2,3-Disubstituted Pyrroles and Pyridines
Gao, Peng,Chen, Huai-Juan,Bai, Zi-Jing,Zhao, Mi-Na,Yang, Desuo,Wang, Juan,Wang, Ning,Du, Lele,Guan, Zheng-Hui
, p. 7939 - 7951 (2020/07/16)
An iodoxybenzoic acid-mediated selected oxidative cyclization of N-hydroxyalkyl enamines was developed. Through this strategy, a variety of 2,3-disubstituted pyrroles and pyridines were produced in good selectivity involving oxidation of alcohol, followed by condensation of aldehyde and α-C of enamines. Furthermore, this metal-free method has several advantages, including the use of environmentally friendly reagents, broad substrate scope, mild reaction conditions, and high efficiency.
Transition metal-free cyclization of N-boc-N-propargylenamines
Chikayuki, Yuya,Higashiyama, Kimio,Ishikawa, Haruka,Kouno, Yasuaki,Sasaki, Shigeru,Teramoto, Hiroyoshi,Waki, Yoko,Yamauchi, Takayasu,Yonekawa, Shiori
, p. 719 - 746 (2020/07/13)
An efficient method for the synthesis of multi-substituted pyrroles was developed using basic cyclization of readily accessible N-Boc-N-propargylenamines. Despite the basic conditions, cleavage of the N-Boc group occurred easily. The process was rapid and afforded N-H-pyrroles with wide functional group tolerance in high yields.
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.
, 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.
Novel and convenient routes to substituted pyrroles and imidazoles
Katritzky, Alan R.,Zhu, Lie,Lang, Hengyuan,Denisko, Olga,Wang, Zuoquan
, p. 13271 - 13276 (2007/10/02)
S-Methyl N-(benzotriazol-1-ylmethyl)thioimidate 6 is obtained by lithiation of the corresponding N-(benzotriazol-1-ylmethyl)thioamide 5 and subsequent reaction with methyl iodide. Derivative 6 undergoes [2+3] cycloaddition reactions with α,β-unsaturated -esters, -ketones and -nitriles, and vinylpyridines which are followed by elimination of benzotriazole and the thioalkoxy group, to give 2,3,4-trisubstituted pyrroles. Lithiation of 6 followed by reactions with imines gives cyclized 4,5-dihydroimidazoles 14 which upon further treatment with ZnBr2 or direct refluxing in toluene yield the 1,2,5-trisubstituted imidazoles 15 in good yields.
