Two novel Diels-Alder adducts from Hippocratea celastroides roots and their insecticidal activity

2000 ◽  
Vol 78 (2) ◽  
pp. 248-254 ◽  
Author(s):  
M Jiménez-Estrada ◽  
R Reyes-Chilpa ◽  
S Hernández-Ortega ◽  
E Cristobal-Telésforo ◽  
L Torres-Colín ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
X Ray Diffraction ◽  
Stored Grain ◽  
X Ray ◽  
Diels Alder Reaction ◽  
Antifeeding Activity ◽  
Hippocratea Celastroides ◽  
Stored Grain Insects

Two novel compounds, celastroidine A (1) and B (2), were isolated from the roots of Hippocratea celastroides K. Their structures were elucidated by spectroscopical and X-ray diffraction studies. Celastroidine A (1) (C50H74O5) was identified as a Diels-Alder adduct of a triterpene plus a diterpene and celastroidine B (2) as a beyerane, a type of dimer of two diterpene (C40H60O4). Both compounds could be formed in vivo by a Diels-Alder reaction. Celastroidine A showed some antifeeding activity against the stored grain insect Sitophyllus zeamays.Key words: Hippocratea celastroides, Hippocrataceae, roots, Diels-Alder adducts, diterpenoids, triterpenoids, x-ray diffraction, insect antifeedants, stored grain insects, Sitophyllus zeamays, insecticidal plants, Diels-Alderase.

Molecular Topology of Linked Anthracenes: X-Ray Structure Analyses of Alkyl Di-9-anthryl-glycolates, 9-Anthryl 9-Anthrylmethyl Ethers and Their Photoisomers

1989 ◽  
Vol 42 (11) ◽  
pp. 1869 ◽  
Author(s):  
HD Becker ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Alder Reaction ◽  
Diels Alder ◽  
Molecular Structures ◽  
Molecular Topology ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diels Alder Reaction ◽  
Photochemical Isomerization ◽  
Spatial Demand

The molecular structures of ethyl di-9-anthrylglycolate (1) and methyl di-9-anthrylglycolate (2), as well as those of three isomerization products of (2), have been established by single-crystal X-ray diffraction studies. In both (1) and (2), the anthracenemoieties are characterized by marked deviations from planarity. The stereospecific course of the thermal and photochemical isomerization of (2) by Diels -Alder reaction is suggested to be governed by the spatial demand of the alkoxycarbonyl group. Base-catalysed isomerization of (2) by migration of 9-anthryl from carbon to oxygen is associated with steric relief.

High-yield, regiospecific bis-functionalization of C70 using a Diels–Alder reaction in molten anthracene

2014 ◽  
Vol 50 (73) ◽  
pp. 10584-10587 ◽  
Author(s):  
Venkata S. Pavan K. Neti ◽  
Maira R. Cerón ◽  
A. Duarte-Ruiz ◽  
Marilyn M. Olmstead ◽  
Alan L. Balch ◽  
...  
Keyword(s):  
Single Crystal ◽  
Thermal Gravimetric Analysis ◽  
Alder Reaction ◽  
Diels Alder ◽  
High Yield ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diels Alder Reaction

A regiospecific bis-adduct of C70 with anthracene was prepared with unusually high yield (68%) by the Diels–Alder reaction in the absence of solvent (melt). The structure of the bis-adduct was an unexpected 12 o'clock isomer, as determined by single crystal X-ray diffraction, thermal gravimetric analysis (TGA) and spectroscopy.

scholarly journals Cooperativity in the Reaction of 9-Methylanthracene With a 1,4-Dithiin Molecule

2014 ◽  
Vol 70 (a1) ◽  
pp. C913-C913
Author(s):  
Sanaz Khorasani ◽  
Manuel Fernandes
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Single Crystal ◽  
Lattice Energy ◽  
Alder Reaction ◽  
Diels Alder ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diels Alder Reaction

Solid-state chemistry involves the manipulation of molecules and materials through photochemical, thermal, or mechanical reaction methods. Single-crystal-to-single-crystal (SCSC) reactions are rare, but offer the opportunity to study reaction mechanisms and molecular motions in the solid state at the atomic level using single crystal X-ray diffraction. This allows the effect of the surrounding molecules, and hence the reaction cavity, on the reacting molecules to be examined which may ultimately lead to postcrystallization methods for creating new materials or reaction products that cannot easily be obtained via solution. SCSC reactions involving two different molecules are relatively uncommon. A convenient system that allows the study of such reactions is the [4+2] Diels-Alder reaction of 1,4-dithiintetracarboxylic type compounds with anthracene derivatives. In the work reported here, electron donor to acceptor interactions between 9-Methylanthracene and bis(N-cyclobutylimino)-1,4-dithiin lead to the formation of chiral charge transfer (CT) crystals [1]. These undergo a topochemical thermal SCSC [4 + 2] Diels-Alder reaction in the solid state. CT crystals were reacted at 400C, their structures determined by X-ray diffraction at various degrees of conversion, and examined using Hirshfeld surfaces and lattice energy calculations to find evidence of reaction cooperativity and feedback mechanisms. In this case, a maximum reaction conversion of around 96% was obtained indicating that the reaction is non-random within the charge transfer stacks, with close contacts between product molecules in the reacted crystal also providing some evidence for reaction cooperativity along the b axis perpendicular to the CT stacking axis.

Temporal Control of Efficient In Vivo Bioconjugation Using a Genetically Encoded Tetrazine-Mediated Inverse-Electron-Demand Diels–Alder Reaction

2020 ◽  
Vol 31 (10) ◽  
pp. 2456-2464
Author(s):  
Byungseop Yang ◽  
Kiyoon Kwon ◽  
Subhashis Jana ◽  
Seoungkyun Kim ◽  
Savanna Avila-Crump ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Temporal Control ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Electron Demand

scholarly journals Two-Carbon Ring Enlargement of Five-, Six-, and Seven-Membered 1-Aza-2-vinylcycloalk-2-enes with Dimethyl Acetylenedicarboxylate and Subsequent Thermal Isomerization Reactions

2006 ◽  
Vol 61 (4) ◽  
pp. 385-395 ◽  
Author(s):  
Gerhard Maas ◽  
Robert Reinhard ◽  
Hans-Georg Herz
Keyword(s):  
Elevated Temperatures ◽  
Alder Reaction ◽  
Thermal Isomerization ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
Ring Enlargement ◽  
Diels Alder Reaction ◽  
Carbon Ring ◽  
Electrocyclic Reaction

2-Aminodienes, in which the enamine function is incorporated in a five-, six-, or seven-membered ring, react with dimethyl acetylenedicarboxylate in a sequence of [2+2] cycloaddition and electrocyclic ring-opening to form the two-carbon ring expanded unsaturated heterocycles, i.e., 3,4- dicarboxylate substituted 6,7-dihydro-1H-azepines 3, 8 and 21, 1,6,7,8-tetrahydroazocines 22, and 6,7,8,9-tetrahydro-1H-azonines 13. Similarly, 2-[(2-thienyl)ethynyl]-4,5,6,7-tetrahydro-1H-azepine 9 is converted into 2-[(2-thienyl)ethynyl]-6,7,8,9-1H-azonine-3,4-dicarboxylate 10 which was characterized by X-ray structure determination. The eight- and nine-membered azaheterocycles 22 and 13, which have not been isolated, undergo thermal isomerization at elevated temperatures. Thus, ring contraction by a 6π-electrocyclic reaction takes place for N-methyl substituted azonine 13, while the N-allyl moiety of azocines 22 engages in an intramolecular Diels-Alder reaction or a 1,7- electrocyclization reaction

scholarly journals Diels-Alder Reaction for Tumor Pretargeting: In Vivo Chemistry Can Boost Tumor Radiation Dose Compared with Directly Labeled Antibody

2013 ◽  
Vol 54 (11) ◽  
pp. 1989-1995 ◽  
Author(s):  
R. Rossin ◽  
T. Lappchen ◽  
S. M. van den Bosch ◽  
R. Laforest ◽  
M. S. Robillard
Keyword(s):  
Radiation Dose ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

ChemInform Abstract: Abnormal Diels-Alder Reaction of 5-Alkoxyoxazoles with Tetracyanoethylene and X-Ray Crystal Structure of an Adduct.

ChemInform ◽  
2010 ◽  
Vol 23 (44) ◽  
pp. no-no
Author(s):  
T. IBATA ◽  
Y. ISOGAMI ◽  
H. NAKAWA ◽  
H. TAMURA ◽  
H. SUGA ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Alder Reaction ◽  
Diels Alder ◽  
X Ray ◽  
Diels Alder Reaction
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