Results 71 to 80 of about 25,619 (230)

1,3-Dipolar Cycloaddition in the Preparation of New Fused Heterocyclic Compounds via Thermal Initiation

open access: yesMolecules, 2016
This paper describes the synthesis of precursors with a benzo[b]furan skeleton for the intramolecular 1,3-dipolar cycloaddition of azomethine ylides prepared from N-substituted 3-allyl-aminobenzo[b]furan-2-aldehydes and secondary amines derived from α ...
Martin Porubský   +2 more
doaj   +1 more source

Regiospecific 1 ,3-Dipolar Cycloaddition Polymerization of Keto-Stabilized Bisalkylidenephosphoranes with Bisazides

open access: yes, 1972
Department of Chemistry, Laboratory of Macromolecular and Organic Chemistry, University of Louvain, B-3030 Heverlee, Belgium Received 4 September 1972 Thennostable poly-1,2,3-triazoles (7) were prepared by the regiospecific rt:action of bisazides with. keto-stabilhed bisalkylidenephosporanes (6) in DMSO solution.
P. YKMAN, G. L' ABBE, G. SMETS
openaire   +2 more sources

Isotelluroureas for Asymmetric C1 Ammonium Enolate Reactions

open access: yesEuropean Journal of Organic Chemistry, EarlyView.
Chiral isotelluroureas are powerful catalysts for a variety of C─C bond forming C1 ammonium enolate transformations. Isotelluroureas (ITeUs) have recently been introduced as a novel class of highly nucleophilic Lewis base catalysts. Herein, we systematically screened them for their potential to facilitate C1 ammonium enolate transformations and ...
Fereshteh Khorasani   +3 more
wiley   +1 more source

1,3-dipolar cycloaddition reactions of C-60 with 3-phenyl-phthalazinium-1-olate. A theoretical study [PDF]

open access: yes, 2002
1,3-Dipolar cycloaddition products of the reaction between C-60 and 1-phenyl-phthalazinium-1-olate were studied within the framework of AM1(RHF) level. The reactions involving the double bond between two hexagons and a hexagon and a pentagon, as well as ...
Türker, Burhan Lemi
core  

Retro‐Hetero‐Michael Addition Strategies in Organic Synthesis

open access: yesEuropean Journal of Organic Chemistry, EarlyView.
In this review, synthetic approaches to carbo‐ and heterocyclic compounds, including natural products, published in the last 15 years (2011–2025) which have either relied upon or included a retro‐hetero‐Michael addition step at any stage are discussed.
Dina Scarpi, Ernesto G. Occhiato
wiley   +1 more source

Synthesis of benzopyranopyrrolidines via 1,3-dipolar cycloaddition of nonstabilized azomethine ylides with 3-substituted coumarins [PDF]

open access: yes, 2013
A three-component reaction of 3-substituted coumarins with N-alkyl-α-amino acids and aldehydes gave 1-benzopyrano[3,4-c]pyrrolidines as a result of a 1,3-dipolar cycloaddition of an intermediate nonstabilized azomethine ylide at the double bond of the ...
Vladimir S. Moshkin   +5 more
core   +1 more source

1, 3-Dipolar Cycloaddition of Diazomethane with Carbon-Carbon Unsaturated Systems Involving Nitrofuran Ring

open access: yesJournal of Synthetic Organic Chemistry, Japan, 1968
1, 3-Dipolar cycloaddition reaction of diazomethane with 5-nitro-2-furylacrylic acid gave 4- (5'-nitro-2'-furyl) -3-carbomethoxypyrazoline (3), mp 184485°C, in 80% yield. A similar reaction with 5-nitro-2-furylpropiolic acid afforded the corresponding isomeric mixture of the 2-pyrazole derivatives in 25% yield. (1) was refluxed in toluene to afford 2- (
SASAKI, Tadashi, SHOJI, Katsuhiko
openaire   +3 more sources

High‐performance electro‐optic materials featuring enhanced thermal stability through dual‐donor structural crosslinking engineering

open access: yesSmart Molecules, EarlyView.
A groundbreaking dual‐donor crosslinking strategy was reported to significantly enhance the thermal stability, achieving remarkable EO coefficients (257–301 pm/V), glass transition temperatures (Tg) ranging from 107–187°C, and ultrahigh chromophore densities (3.73–4.26 × 10²⁰ molecules/cm³) with exceptional long‐term stability after 500 h at 85°C ...
Yu Zhang   +7 more
wiley   +1 more source

Creating a Masterpiece. The Road to (and Beyond) Woodward and Hoffmann's 1969 Angewandte Chemie Treatise

open access: yesThe Chemical Record, EarlyView.
This publication describes how R. B. Woodward and Roald Hoffmann crafted their masterpiece publications. Illustrations include Woodward's first draft of the famous “Violations There are none. Nor can violations be expected of so fundamental a principle of maximum bonding.” Original but discarded text shows the stepwise paths toward the W‐H masterpieces.
Jeffrey I. Seeman
wiley   +1 more source

Late‐Stage Functionalization of Peptides on the Solid Phase

open access: yesAngewandte Chemie International Edition, Volume 65, Issue 31, 27 July 2026.
Peptide modifications are essential to control pharmacodynamic and pharmacokinetic properties of peptide drugs. Consequently, strategies that allow for efficient and rapid incorporation of non‐canonical modifications into peptides in parallel formats are highly sought after.
Marius Werner   +2 more
wiley   +1 more source

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