Results 21 to 30 of about 5,904 (191)

Synthesis of 1,4-Disubstituted Mono and Bis-triazolocarbo-acyclonucleoside Analogues of 9-(4-Hydroxybutyl)guanine by Cu(I)-Catalyzed Click Azide-Alkyne Cycloaddition [PDF]

open access: yes, 2011
A series of novel mono-1,2,3-triazole and bis-1,2,3-triazole acyclonucleoside analogues of 9-(4-hydroxybutyl)guanine was prepared via copper(I)-catalyzed 1,3-dipolar cycloaddition of N-9 propargylpurine, N-1-propargylpyrimidines/as-triazine with the ...
Krim, Jamal   +5 more
core   +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

open access: yesAngewandte 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   +7 more
wiley   +2 more sources

Synthesis and cytotoxic evaluation of substituted 3-(3′-indolyl-/3′-pyridyl)-isoxazolidines and bis-indoles

open access: yesActa Pharmaceutica Sinica B, 2012
Regio- and stereoselective 1,3-dipolar cycloadditions of C-(3-indolyl)-N-phenylnitrone (10) were carried out with different mono-substituted, disubstituted and cyclic dipolarophiles under mono-mode microwave irradiation to obtain substituted 3-(indol-3 ...
Vishal Sharma   +9 more
doaj   +1 more source

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

open access: yesAngewandte 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

open access: yesChemical 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

Intramolecular 1,3-Dipolar Cycloadditions of Norbornadiene-Tethered Nitrones [PDF]

open access: yes, 2016
Efficient routes to the synthesis of norbornadiene-tethered nitrones have been developed, and their intramolecular 1,3-dipolar cycloadditions were studied.
Geoffrey K. Tranmer (2520547)   +1 more
core   +3 more sources

Intermolecular 1,3-dipolar cycloadditions of azomethine imines [PDF]

open access: yes, 2006
Dipolar cycloadditions of azomethine imines, formed in situ from aldehydes and N1-alkyl-N2-acylhydrazines, with electron-deficient dipolarophiles produce pyrazolidines: mono-substituted dipolarophiles afford principally 4-substituted ...
Raymond C. F. Jones   +5 more
core   +1 more source

Synthesis of Spiroisoxazolines by 1,3-Dipolar Cycloaddition

open access: yesMolecules, 1997
The cycloaddition of the chiral nitrile oxide 1 to 1-R-substituted 3,3-methylene-5,5-dimethyl-2-pyrrolidinones 2 (where R is H, n-butyl-, 1,1-dimethylethoxycarbonyl-, 1-methylethenyl- and acetyl-) proceeds regioselectively under the formation of ...
Peter Ertl   +3 more
doaj   +1 more source

1,3-Dipolar cycloadditions of azomethine imines [PDF]

open access: yes, 2015
Azomethine imines are considered 1,3-dipoles of the aza-allyl type which are transient intermediates and should be generated in situ but can also be stable and isolable compounds.
Nájera, Carmen   +2 more
core   +2 more sources

Theoretical Study of 1,3-Dipolar Cycloadditions Regioselectivity of Benzyl Azide with Glycosyl-O Acetylene Using Density Functional Theory (DFT)

open access: yesOrbital: The Electronic Journal of Chemistry, 2017
A theoretical study of 1,3-cycloaddition has been carried out using density functional theory (DFT) methods at the B3LYP/6-31G* level. The regioselectivity of the reaction have been clarified through different theoretical approaches: Case of a Two-Center
Adib Ghaleb   +5 more
doaj   +1 more source

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