Remendable thermosetting polymers for isocyanate-free adhesives: a preliminary study

2015 ◽  
Vol 6 (45) ◽  
pp. 7851-7861 ◽  
Author(s):  
Elena Dolci ◽  
Guillaume Michaud ◽  
Frédéric Simon ◽  
Bernard Boutevin ◽  
Stéphane Fouquay ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Cyclic Monomer ◽  
Diels Alder Reaction ◽  
Model Study ◽  
Thermosetting Polymers ◽  
Preliminary Study ◽  
Alder Adduct

Based on a model study, a new bis-cyclic monomer bearing a Diels–Alder adduct was synthesized. This monomer was polymerized with a diamine to yield a thermoresponsive polyhydroxyurethane (PHU). This PHU is remendable at around 100 °C by retro Diels–Alder reaction.

scholarly journals Crystal structures and conformations of two Diels–Alder adduct derivatives: 1,8-bis(thiophen-2-yl)-14-oxatetracyclo[6.5.1.02,7.09,13]tetradeca-2(7),3,5-trien-10-one and 1,8-diphenyl-14-oxatetracyclo[6.5.1.02,7.09,13] tetradeca-2,4,6-trien-10-one

2015 ◽  
Vol 71 (2) ◽  
pp. 213-216
Author(s):  
S. Gopinath ◽  
P. Narayanan ◽  
K. Sethusankar ◽  
Meganathan Nandakumar ◽  
Arasambattu K. Mohanakrishnan
Keyword(s):  
Crystal Packing ◽  
Rotation Axis ◽  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Compound I ◽  
Diels Alder Reaction ◽  
Phenyl Rings ◽  
Axis Parallel ◽  
Alder Adduct

The title compounds, C21H16O2S2(I) and C25H20O2(II), are products of a tandem `pincer' Diels–Alder reaction consisting of [2 + 2] cycloadditions between benzo[c]furan and cyclopentanone. Each comprises a fused tetracyclic ring system containing two five-membered rings (inenvelopeconformations with the O atom as the flap) and six-membered rings (inboatconformations). In addition, two thiophene rings in (I) and two phenyl rings in (II) are attached to the tetracyclic ring system. The cyclopentanone ring adopts atwistedconformation in (I) and anenvelopeconformation in (II). In (I), the thiophene rings are positionally disordered over two sets of sites, with occupancy ratios of 0.901 (2):0.099 (2) and 0.666 (2):0.334 (2). In (II), the oxygen atom of the cyclopentanone ring is rotationally disordered over two sites with an occupancy ratio of 0.579 (4):0.421 (4). The molecular structure of (I) is stabilized by an intramolecular C—H...O hydrogen bond, which generates anS(7) ring motif. In the crystal, the molecules are linkedviaweak C—H...O hydrogen bonds, which generateR22(16) ring motifs in (I) andC(8) chains in (II). In both structures, the crystal packing also features C—H...π interactions. The crystal studied of compound (I) was twinned by non-merohedry. The twin component is related by the twin law [−1 0 0 −0.101 1 −0.484 0 0 −1] operated by a twofold rotation axis parallel to thebaxis. The structure of (I) was refined with a twin scale factor of 0.275 (2).

scholarly journals Hetero Diels-Alder adduct formation between nitrosobenzene and tetra-methyl purpurogallin and its retro-Diels-Alder reaction

2001 ◽  
Vol 12 (4) ◽  
Author(s):  
Daniela Gamenara ◽  
Eduardo Días ◽  
Néstor Tancred ◽  
Horacio Heinzen ◽  
Patrick Moyna ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Adduct Formation ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Alder Adduct

Synthesis of (±)-epiisopodophyllotoxin

1983 ◽  
Vol 61 (3) ◽  
pp. 573-575 ◽  
Author(s):  
Margaret B. Glinski ◽  
Tony Durst
Keyword(s):  
Title Compound ◽  
Dimethyl Fumarate ◽  
Dimethyl Acetal ◽  
Alder Reaction ◽  
Diels Alder ◽  
Carbon Skeleton ◽  
Diels Alder Reaction ◽  
Alder Adduct

The synthesis of (±)-epiisopodophyllotoxin commencing with 6-bromopiperonal dimethyl acetal is described. The carbon skeleton of isoepipodophyllotoxin was assembled via a Diels–Alder reaction between the hydroxyquinodimethane generated photochemically from 6-(3′,4′,5′-trimethoxybenzyl)-piperonal, obtained from the bromoacetal above, and dimethyl fumarate. This Diels–Alder adduct was converted in five steps into the title compound. The overall yield for the seven steps was 15%.

Diels–Alder reaction of tetraarylcyclopentadienones with benzo[b]thiophene S,S-dioxides: an unprecedented de-oxygenation vs. sulfur dioxide extrusion

2020 ◽  
Vol 56 (97) ◽  
pp. 15317-15320
Author(s):  
Palani Manikandan ◽  
Jayachandran Karunakaran ◽  
Elumalai Varathan ◽  
Georg Schreckenbach ◽  
Arasambattu K Mohanakrishnan
Keyword(s):  
Sulfur Dioxide ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Alder Adduct

The Diels–Alder adduct, dihydrodibenzothiophene S,S-dioxides underwent aromatization either through de-oxygenation or extrusion of sulfur dioxide to furnish substituted dibenzothiophenes or benzenes.

scholarly journals Stereocontrolled chiral synthesis of a trans-anti-trans tricycle by a transannular Diels–Alder reaction

1992 ◽  
Vol 70 (9) ◽  
pp. 2350-2364 ◽  
Author(s):  
Anne Marinier ◽  
Pierre Deslongchamps
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Chiral Synthesis ◽  
Diels Alder Reaction ◽  
Tricyclic Compound ◽  
Preliminary Study

The racemic and chiral synthesis of trans-cis-cis macrocyclic triene 5 is described. Heating this compound at 262 °C leads via a transannular Diels–Alder reaction to the tricyclic structure 6, which can be further transformed into tricyclic compound 7. This work constitutes a preliminary study for the synthesis of corticoids.

Syntheses of Angucyclinones Related to Ochromycinone

1998 ◽  
Vol 51 (6) ◽  
pp. 515 ◽  
Author(s):  
Tomas Rozek ◽  
Wit Janowski ◽  
John M. Hevko ◽  
Edward R. T. Tiekink ◽  
Suresh Dua ◽  
...  
Keyword(s):  
Structural Study ◽  
Alder Reaction ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Diels Alder Reaction ◽  
Synthetic Approaches ◽  
Alder Adduct

Two synthetic approaches have been investigated for the syntheses of model angucyclinones related to ochromycinone. The first involves a Diels–Alder/Friedel–Crafts strategy in which the Diels–Alder adduct formed between dimethyl acetylenedicarboxylate and 3-ethenyl-5,5-dimethylcyclohex-2-en-1- one was converted into 6,6-dimethyl-8-oxo-5,6,7,8-tetrahydronaphthalene-1,2-dicarboxylic anhydride, which was then reacted with benzene in a Friedel–Crafts reaction. Acid-catalysed cyclization of the Friedel–Crafts products gave 3,3-dimethyl-3,4-dihydrobenz[a]anthracene-1,7,12(2H)-trione (3) in poor yield. Angucyclinones related to (3) are formed (in 40–50% overall yield) by aromatization of the adduct formed between the appropriate 1,4-naphthoquinone and 3-[(E)-2-methoxyethenyl]- 5,5-dimethylcyclohex-2-en-1-one (this dienone reacts with itself by a Diels–Alder process to yield an adduct which decomposes to 3,3,8,8-tetramethyl-3,4,7,8-tetrahydroanthracene-1,6(2H,5H)-dione). When the substituted 1,4-naphthoquinone is unsymmetrical, a boron triacetate assisted Diels–Alder reaction gives a single regioisomer (e.g. X-ray investigations indicate that 8-hydroxy-3,3-dimethyl-3,4-dihydrobenz[a]anthracene-1,7,12(2H)-trione is the product from 5-hydroxy-1,4-naphthoquinone). An X-ray structural study of the Diels–Alder adduct in the above reaction confirms the operation of an endo cyclization.

scholarly journals Stepwise radical cation Diels–Alder reaction via multiple pathways

2018 ◽  
Vol 14 ◽  
pp. 704-708 ◽  
Author(s):  
Ryo Shimizu ◽  
Yohei Okada ◽  
Kazuhiro Chiba
Keyword(s):  
Radical Cation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Vinyl Ethers ◽  
Diels Alder Reaction ◽  
Alder Adduct

Herein we disclose the radical cation Diels–Alder reaction of aryl vinyl ethers by electrocatalysis, which is triggered by an oxidative SET process. The reaction clearly proceeds in a stepwise fashion, which is a rare mechanism in this class. We also found that two distinctive pathways, including “direct” and “indirect”, are possible to construct the Diels–Alder adduct.

scholarly journals Thermally Healable and Recyclable Graphene-Nanoplate/Epoxy Composites Via an In-Situ Diels-Alder Reaction on the Graphene-Nanoplate Surface

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1057 ◽  
Author(s):  
Cho-Rong Oh ◽  
Dae-Il Lee ◽  
Jun-Hong Park ◽  
Dai-Soo Lee
Keyword(s):  
Bisphenol A ◽  
Epoxy Resin ◽  
Low Temperatures ◽  
Diglycidyl Ether ◽  
Alder Reaction ◽  
Diels Alder ◽  
Epoxy Composites ◽  
Diels Alder Reaction ◽  
Thermosetting Polymers

In this work, thermally healable graphene-nanoplate/epoxy (GNP/EP) nanocomposites were investigated. GNPs were used as reinforcement and crosslinking platforms for the diglycidyl ether of bisphenol A-based epoxy resin (DGEBA) through the Diels-Alder (DA) reaction with furfurylamine (FA). The GNPs and FA could then be used as a derivative of diene and dienophile in the DA reaction. It was expected that the combination of GNPs and FA in DGEBA would produce composites based on the interfacial properties of the components. We confirmed the DA reaction of GNPs and FA at the interface during curing of the GNP/EP nanocomposites. This procedure is simple and solvent-free. DA and retro DA reactions of the obtained composites were demonstrated, and the thermal healing properties were evaluated. The behavior of the GNP/EP nanocomposites in the DA reaction is similar to that of thermosetting polymers at low temperatures due to crosslinking by the DA reaction, and the nanocomposites can be recycled by a retro DA reaction at high temperatures.

Syntheses of Angucyclinones Related to Ochromycinone. III. An 11-Hydroxy Isomer and Some Reduced Analogues

1999 ◽  
Vol 52 (2) ◽  
pp. 129 ◽  
Author(s):  
Tomas Rozek ◽  
Tomas Rozek ◽  
Dennis K. Taylor ◽  
Dennis K. Taylor ◽  
Edward R. T. Tiekink ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Alder Reaction ◽  
Diels Alder ◽  
X Ray ◽  
X Ray Crystallography ◽  
Diels Alder Reaction ◽  
Stereo Selectivity ◽  
Hydrolysis Of ◽  
Alder Adduct

The boron triacetate assisted Diels Alder reaction between racemic 5,5-dimethyl-3-vinylcyclohex- 2-enyl acetate and 5-hydroxynaphthoquinone yields the racemic 11-hydroxy-3,3-dimethyl-7,12-dioxo- 1,2,3,4,6,6a,7,12,12a,12b-decahydrobenzo[a]anthracen-1-yl acetate as the sole stereoisomer by regio- and stereo-selective cis endo addition. Aromatization of the Diels Alder adduct followed by hydrolysis of the acetate and oxidation of the resultant 1-hydroxy group gives the target angucyclinone, 11-hydroxy-3,3-dimethyl-1,2,3,4,7,12-hexahydrobenzo[a]anthracene-1,7,12-trione, in an overall yield of 37% from 5-hydroxynaphthoquinone. The regio- and stereo-selectivity of the Diels Alder addition is confirmed by a combination of 13C n.m.r. spectroscopy and X-ray crystallography.

Sign in / Sign up

Export Citation Format

Share Document