Results 71 to 80 of about 37,566 (244)

Unveiling the Origin of the Selectivity and the Molecular Mechanism in the [3+2] Cycloaddition Reaction of N-aryl-C-carbamoylnitrone with N-arylitaconimide

Organics, 2022
The [3+2] cycloaddition reaction of N-aryl-C-carbamoylnitrone (nitrone 1) with N-arylitaconimide (ethylene 2) was computationally studied using the B3LYP/6-31G(d) level of theory. An analysis of the different energetic profiles and the transition states’
Abdelmalek Khorief Nacereddine, Fouad Chafaa   +1 more
doaj   +1 more source

Ligand-controlled regiodivergent arylation of aryl(alkyl)alkynes and asymmetric synthesis of axially chiral 9-alkylidene-9,10-dihydroanthracenes

Nature Communications
Transition metal-catalyzed addition of organometallics to aryl(alkyl)alkynes has been well known to proceed with the regioselectivity in forming a carbon–carbon bond at the alkyl-substituted carbon (β-addition).
Chao Sun, Ting Qi, Faiz-Ur Rahman, Tamio Hayashi, Jialin Ming   +4 more
doaj   +1 more source

Heterogeneous Catalysts in Pictet-Spengler-Type Reactions

Journal of Chemistry, 2013
Several solid catalysts were evaluated as an alternative for 1,2,3,4-tetrahydroisoquinoline synthesis by means of the Pictet-Spengler reaction. The reaction catalysed by a mixed oxide (Mg and Al) led to the best yield and good regioselectivity; using an ...
Rodolfo Quevedo, Camilo Perdomo, Sonia Moreno   +2 more
doaj   +1 more source

A Simple and Easily Implemented Method for the Regioselective Introduction of Deuterium into Azolo[1,5-a]pyrimidines Molecules

Molecules, 2023
A method for the technically easy-to-implement synthesis of deuterium-labeled pyrazolo[1,5-a]pyrimidines and 1,2,4-triazolo[1,5-a]pyrimidines have been developed. The regioselectivity of such transformations has been shown.
Gevorg G. Danagulyan, Henrik A. Panosyan, Vache K. Gharibyan, Ani H. Hasratyan   +3 more
doaj   +1 more source

Tailoring Regioselectivity‐Controlled UDP‐Glycosyltransferase for Bidirectional Glycosylation of Tyrosol via Free Energy‐Driven Pocket Reshaping and Tunnel Engineering

Advanced Science
UDP‐glycosyltransferases (UGTs) are pivotal biocatalysts for synthesizing pharmaceutically valuable active components; however, their application is frequently constrained by poor regioselectivity and suboptimal catalytic efficiency.
Ziyu Zhang, Jingyi Chen, Zuozhi Liang, Wenming Shao, Zhen Gao, Bin Wu, Bingfang He, Gerhard Schenk   +7 more
doaj   +1 more source

Semi-rational engineering of an α-L-fucosidase for regioselective synthesis of fucosyl-N-acetylglucosamine disaccharides

Food Chemistry: Molecular Sciences
α-L-Fucosidases are attractive biocatalysts for the production of bioactive fucosylated oligosaccharides, however, poor regioselectivity and activity for transglycosylation have significantly limited their applications.
Peng Liu, Xiaodi Chen, Xueting Cao, Yuying Wang, Yafei Gao, Li Xu, Xukai Jiang, Min Xiao   +7 more
doaj   +1 more source

A Straightforward Selective Acylation of Phenols over ZSM-5 towards Making Paracetamol Precursors

Bulletin of Chemical Reaction Engineering & Catalysis, 2018
Commercially available ZSM-5 was minimally treated as the catalyst to selectively acylate phenols. The ZSM-5 was simply immersed in ammonium nitrate in order to fill the pores with Brönsted acid to concentrate the catalytic reactions inside the pores ...
Robby Roswanda, Alfhons Daniel Sirampun, Rino Rakhmata Mukti, Didin Mujahidin   +3 more
doaj   +1 more source

Exploring the Potential of Cytochrome P450 CYP109B1 Catalyzed Regio—and Stereoselective Steroid Hydroxylation

Frontiers in Chemistry, 2021
Cytochrome P450 enzyme CYP109B1 is a versatile biocatalyst exhibiting hydroxylation activities toward various substrates. However, the regio- and stereoselective steroid hydroxylation by CYP109B1 is far less explored.
Xiaodong Zhang, Yun Hu, Wei Peng, Chenghua Gao, Qiong Xing, Binju Wang, Aitao Li   +6 more
doaj   +1 more source

Regioselectivity in Hetero Diels–Alder Reactions

, 2019
Regioselectivity in hetero Diels-Alder reactions can be observed in a simple reaction between a nonsymmetrical heterodiene and an unsymmetrical heterodienophile.
Liber, Marta, Amadeu F. Brigas, Teresa M. V. D. Pinho e Melo, Lemos, Americo, Carla Grosso, Marta Liber, Américo Lemos, Brigas, Amadeu, Grosso, Carla, Pinho e Melo, Teresa M. V. D.   +9 more
core   +1 more source

Regioselectivity in the Nitration of Dialkoxybenzenes

, 2016
Dinitrodialkoxybenzene derivatives are important precursors for Schiff base macrocycles and a variety of other molecules. During our investigations, we have found that the dinitration reaction of 1,2-dialkoxybenzenes proceeds with unusual ...
Kevin Shopsowitz (2226526), Mark J. MacLachlan (1263879), Francesco Lelj (1600021)   +2 more
core   +1 more source