Results 21 to 30 of about 25,619 (230)

Synthesis of novel pyrazoles via [2+3]-dipolar cycloaddition using alkyne surrogates [PDF]

Tetrahedron Letters, 2010
The syntheses of an important class of hitherto unreported novel pyrazoles are described. The regioselective synthesis of 1,3,4,5-tetrasubstituted pyrazoles was achieved by the Huisgen cyclization of nitrile imines with a trisubstituted bromoalkene. The substituted bromoalkene functions as an alkyne synthon which was used to construct 5,5-disubstituted
Sureshbabu, Dadiboyena, Edward J, Valente, Ashton T, Hamme   +2 more
openaire   +2 more sources

Construction of nine-membered N,N,O-heterocycles via Pd-catalyzed [6+3] dipolar cycloaddition [PDF]

, 2022
A new approach for the synthesis of 9-membered N,N,O-heterocycles by Pd-catalyzed [6+3] dipolar cycloaddition of N-iminoisoquinolinium ylides and 2-vinyl oxetanes has been developed. The scope of this cycloaddition was demonstrated with 28 examples. This
Han, Zhengyu, Huang, Hai, Xie, Hongling, Sun, Jianwei, Yang, Zhenkun, Tang, Luning   +5 more
core   +1 more source

Dimerization of propargyl and homopropargyl 6-azido-6-deoxy-glycosides upon 1,3-dipolar cycloaddition

Beilstein Journal of Organic Chemistry, 2008
Copper-catalyzed, thermal or microwave promoted 1,3-dipolar cycloaddition (Click Reaction) of 2-propynyl and 3-butynyl 2,3,4-tri-O-acetyl-6-azido-6-deoxy-glycopyranosides in the D-gluco, D-galacto and D-manno series afford the corresponding dimeric ...
Nikolas Pietrzik, Daniel Schmollinger, Thomas Ziegler   +2 more
doaj   +1 more source

Side-chain Modifications of Highly Functionalized 3(2H)-Furanones

Molecules, 2012
A series of 3(2H)-furanones, based on side-chain modifications of a parent 3(2H)-furanone, was synthesized in good yield. The parent compound was prepared by hydrogenolysis, and subsequent acid hydrolysis, of isoxazole derivatives.
Gil Valdo José da Silva, Maurício Gomes Constantino, Viviani Nardini, Shirley Muniz Machado Rodrigues   +3 more
doaj   +1 more source

Diastereoselective Formal 1,3-Dipolar Cycloaddition of Trifluoroethyl Amine-Derived Ketimines Enables the Desymmetrization of Cyclopentenediones

Molecules, 2023
In this research, a metal-free diastereoselective formal 1,3-dipolar cycloaddition of N-2,2,2-trifluoroethylisatin ketimines and cyclopentene-1,3-diones which can efficiently lead to the desymmetrization of cyclopentene-1,3-diones is developed.
Lin-Qiang Li, Jian-Qiang Zhao, Yan-Ping Zhang, Yong You, Zhen-Hua Wang, Zhen-Zhen Ge, Ming-Qiang Zhou, Wei-Cheng Yuan   +7 more
doaj   +1 more source

Domino Multicomponent Approach for the Synthesis of Functionalized Spiro-Indeno[1,2-b]quinoxaline Heterocyclic Hybrids and Their Antimicrobial Activity, Synergistic Effect and Molecular Docking Simulation

Molecules, 2019
An expedient synthesis of hitherto unexplored novel hybrid heterocycles comprising dispiropyrrolidine, N-styrylpiperidone and indeno[1,2-b]quinoxaline units has been developed via domino multicomponent 1,3-dipolar cycloaddition strategy employing a new ...
Abdulrahman I. Almansour, Natarajan Arumugam, Raju Suresh Kumar, Dhaifallah M. Al-thamili, Govindasami Periyasami, Karuppiah Ponmurugan, Naif Abdullah Al-Dhabi, Karthikeyan Perumal, Dhanaraj Premnath   +8 more
doaj   +1 more source

Photo‐Triggered, Fast, and Fluorogenic Thiophene‐Based Cycloalkynes for the Bioorthogonal Fluorescent Labeling of 1,3‐Dipole‐Tagged Molecules in No‐Wash Conditions

Angewandte Chemie, EarlyView.
Thiophene is king! The fusion of thiophene rings to cycloalkynes super‐charged their copper‐free click chemistry applications, by (1) enhancing the alkyne reactivity (fastest cyclooctyne to date) and (2) rendering the alkyne fluorogenic (with fluorescence enhancement up to 150‐fold upon reaction), making these bioorthogonal reagents ideal for tracking ...
Jurgen Schulz, Zoeisha S. Chinoy, Tarek Khalaf, Yukang Li, Pengchen Ma, Dennis Svatunek, Kendall N. Houk, Frédéric Friscourt   +7 more
wiley   +2 more sources

1,3-Dipolar Cycloadditions of N-Benzyl Furfuryl Nitrones with Electron-rich Alkenes

Molecules, 2000
The 1,3-dipolar cycloaddition reaction of N-benzyl-C-(2-furyl)nitrones with electron-rich alkenes gives preferentially trans-substituted 3,5-disubstituted isoxazolidines (endo approach).
Tomas Tejero, Francisco L. Merchan, Sonia Anoro, Pedro Merino   +3 more
doaj   +1 more source

Organocatalytic Enantioselective Addition of Malonates to Cyclic Imines: A Short Total Synthesis of Tetraponerine T‐1

Angewandte Chemie, EarlyView.
A stereoselective functionalization method of cyclic imines under mild organocatalytic conditions was developed. Bifunctional cinchona alkaloid catalysts combined with carefully optimized reaction conditions to suppress background reactivity enabled highly enantio‐ and diastereoselective addition reactions of malonates to cyclic imines.
Frederic Kölblin, Helma Wennemers
wiley   +2 more sources

Photo-induced 1, 3-Dipolar Cycloaddition Reaction of Aziridinedicarboximide

Chemical and Pharmaceutical Bulletin, 1969
Cycloaddition reaction of N-(p-methoxyphenyl)-1-benzyl-2, 3-aziridinedicarboximide (8) with dimethyl acetylenedicarboxylate (3) was not effected thermally, but under irradiation it resulted in a formation of 1 : 1-cycloadducts, I (9), II (17), and III (34), and a 1 : 2-cycloadduct IV (38).
OIDA, SADAO, OHKI, EIJI
openaire   +2 more sources