73500-16-0Relevant articles and documents
Regioselective reduction of 1h-1,2,3-triazole diesters
Butler, Christopher R.,Bendesky, Justin,Schoffstall, Allen Milton
, (2021/09/24)
Regioselective reactions can play pivotal roles in synthetic organic chemistry. The reduction of several 1-substituted 1,2,3-triazole 4,5-diesters by sodium borohydride has been found to be regioselective, with the C(5) ester groups being more reactive towards reduction than the C(4) ester groups. The amount of sodium borohydride and reaction time required for reduction varied greatly depending on the N(1)-substituent. The presence of a β-hydroxyl group on the N(1)-substituent was seen to have a rate enhancing effect on the reduction of the C(5) ester group. The regioselective reduction was attributed to the lower electron densities of the C(5) and the C(5) ester carbonyl carbon of the 1,2,3-triazole, which were further lowered in cases involving intramolecular hydrogen bonding.
Visible-Light-Mediated Click Chemistry for Highly Regioselective Azide–Alkyne Cycloaddition by a Photoredox Electron-Transfer Strategy
Wu, Zheng-Guang,Liao, Xiang-Ji,Yuan, Li,Wang, Yi,Zheng, You-Xuan,Zuo, Jing-Lin,Pan, Yi
supporting information, p. 5694 - 5700 (2020/04/24)
Click chemistry focuses on the development of highly selective reactions using simple precursors for the exquisite synthesis of molecules. Undisputedly, the CuI-catalyzed azide–alkyne cycloaddition (CuAAC) is one of the most valuable examples of click chemistry, but it suffers from some limitations as it requires additional reducing agents and ligands as well as cytotoxic copper. Here, we demonstrate a novel strategy for the azide–alkyne cycloaddition reaction that involves a photoredox electron-transfer radical mechanism instead of the traditional metal-catalyzed coordination process. This newly developed photocatalyzed azide–alkyne cycloaddition reaction can be performed under mild conditions at room temperature in the presence of air and visible light and shows good functional group tolerance, excellent atom economy, high yields of up to 99 %, and absolute regioselectivity, affording a variety of 1,4-disubstituted 1,2,3-triazole derivatives, including bioactive molecules and pharmaceuticals. The use of a recyclable photocatalyst, solar energy, and water as solvent makes this photocatalytic system sustainable and environmentally friendly. Moreover, the azide–alkyne cycloaddition reaction could be photocatalyzed in the presence of a metal-free catalyst with excellent regioselectivity, which represents an important development for click chemistry and should find versatile applications in organic synthesis, chemical biology, and materials science.
An efficient and recyclable thiourea-supported copper(i) chloride catalyst for azide-alkyne cycloaddition reactions
Barman, Milan Kr.,Sinha, Ashish Kumar,Nembenna, Sharanappa
, p. 2534 - 2541 (2016/05/19)
A reaction between two equivalents of bulky thiourea, i.e., 1,3-bis(2,6-dimethylphenyl)thiourea (L) [L = (ArNH)2C = S; Ar = 2,6-Me2C6H3], and CuCl2 or CuCl in THF solvent afforded a bulky thiourea-sta
