- Transition metal-catalyzed [4 + 2 + 2] cycloadditions of bicyclo[2.2.1]hepta-2,5-dienes (Norbornadienes) and bicyclo[2.2.2]octa-2,5-dienes
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The transition-metal-catalyzed [4 + 2 + 2] cycloadditions of norbornadienes, bicyclo[2.2.2]octa-2,5-diene, and benzobarrelene with 1,3-butadienes proceed in excellent yields using cobalt-based catalytic systems. Two key distinctions between these [4 + 2 + 2] cycloadditions and the corresponding transition-metal-catalyzed [2 + 2 +2] reactions of norbornadiene are the requirement of a bimetal catalytic system with a bisphosphine ligand for the former and exclusive regioselectivity in the [4 + 2 + 2] reaction of 2-substituted norbornadienes to produce 1-substituted adducts. These distinctions may indicate two distinct mechanisms for the [4 + 2 + 2] and [2 + 2 + 2] reactions.
- Chen,Kiattansakul,Ma,Snyder
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- Catalytic Isomerisation of Water-Soluble Quadricyclane to Norbornadiene Derivatives Induced by Cobalt-Porphyrin Complexes
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In an aqueous alkaline solution, the exothermic isomerisation of quadricyclane derivatives to norbornadiene derivatives catalyzed by cobalt-porphyrin complexes was investigated.By catalytic action of cobalt 5,10,15,20-tetrakis(p-carboxyphenyl)porphyrin (Co-TPPC), thermally stable and water-soluble quadricyclane derivatives 1a-l isomerised to the corresponding norbornadiene derivatives 2a-l quantitatively and suddenly even at room temperature in an aqueous sodium carbonate solution.It was seen that larger hydrophobicities of 1 enhanced the isomerization rate.The attacking direction of cobalt porphyrins toward quadricyclanes might be to the five-membered ring, which was different from that suggested in the action of Rh catalyst, i.e., attack to the three-membered ring.
- Maruyama, Kazuhiro,Tamiaki, Hitoshi
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- Ring Opening Metathesis Polymerization of Bicyclic α,β-Unsaturated Anhydrides for Ready-to-be-grafted Polymers Having Tailored pH-Responsive Degradability
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Polymers having α,β-unsaturated anhydrides as repeating units were synthesized by ring opening metathesis polymerization (ROMP). The anhydride moieties were ready-to-be-grafted with amines to form acid-labile cis-α,β-unsaturated acid amide linkages. The pH-responsive reversible de-grafting can be controlled by changing the intramolecular accessibility between acid and amide groups. The alendronate-grafted ROMP polymers showed distinct pH-dependent cytotoxicity according to the anhydride structures.
- Kim, Heejin,Kim, Sungwhan,Kang, Sunyoung,Song, Youngjun,Shin, Suyong,Lee, Seonju,Kang, Minji,Nam, So Hee,Lee, Yan
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- Addition Reactions to syn- and anti-Sesquinorbornenes Involving Ionic Mechanisms. The Role of Tetracyanoethylene
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Addition of bromine or of acids to anti-sesquinorbornene is more rapid and less readily reversible than that to the syn isomer, whereas other addition reactions proceeding by concerted or free-radical mechanisms show a small rate advantage for syn-sesquinorbornene and no reversibility.Tetracyanoethylene (TCNE) does not undergo cycloaddition with syn- or anti-sesquinorbornene, nor can any dipolar ion from TCNE and sesquinorbornene be trapped by methanol, as in the case of TCNE and vinyl ethers.However, under the conditions of such experiments TCNE catalyzes the addition of methanol to yield sesquinorbornyl methyl ether, or of water to yield sesquinorbornanol, the TCNE undergoing no apparent chemical change.From a comparative study of TCNE and p-toluenesulfonic acid it is concluded that the TCNE reaction is an example of acid catalysis, probably by the complex between TCNE and the alcohol or water. syn-Sesquinorbornene adds methanol in CD3CN with the lower equilibrium constant of about 0.54 +/- 0.05 L/mol at ca. 30 deg C. anti-Sesquinorbornene in similar additions shows an equilibrium more favorable to addition by about 3 orders of magnitude.These reactions are discussed in light of the general character and behavior of the sesquinorbornenes.A new route to anti-sesquinorbornene is described that gives better yields than the former electrolytic preparation.
- Bartlett, Paul D.,Roof, Antonius A. M.,Subramanyam, Ravi,Winter, William J.
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- Photochemical isomerization of norbornadiene-containing polytriazoles obtained by click chemistry polyaddition
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Polyesters and polyethers containing norbornadiene (NBD) and 1,2,3-triazole units in the main chain are prepared by step growth polymerization of diester or diether NBD-based dialkynes with different aromatic diazides using copper-catalyzed azide-alkyne c
- Miladi, Imen Abdelhedi,Mudraboyina, Bhanu Prakash,Oueslati, Ahmed,Drockenmuller, Eric,Romdhane, Hatem Ben
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- Structure and NMR spectra of bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylic acid and its Anhydride
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Two of the three published sets of 1H and 13C NMR data for bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylic anhydride have been found to actually be those of the corresponding diacid. The NMR spectroscopic distinction between these two compounds is clarified and 1JC–H values are reported for the anhydride, the diacid and a related diester. The X-ray structure of the diacid has been determined and features chains of molecules involving both intra- and inter-molecular hydrogen bonding.
- Aitken, R. Alan,Fotherby, Fiona M.,Slawin, Alexandra M.Z.
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- Synthesis and Evaluation of Nematicidal Activity of Compounds Derived from Norbornadiene
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Nematode is a major problem in agriculture, the effective way to control this pest is through chemical control, but the efficient molecules present in the market have great toxicity to mammals and birds. Thus, there is a constant demand for the development of new nematicide molecules. This study describes the synthesis of 21 novel esters derived from norbornadiene and evaluation of their potential activity against Meloidogyne javanica. The esters 5-25 presented 50% mortality of the nematodes. The acid 3 and the ester 4 caused 96 and 93% mortality of the nematodes, respectively. The lethal concentration to kill 50% of the nematodes (LD50) were determined as being 11.8 μg mL?1 for the acid 3 and 99.4 μg mL?1 for the ester 4. According to the results obtained it is believed that polarity seems to be a key factor for the higher activity of compound 3 compared to structurally similar ester derivatives.
- Alvarenga, Elson S.,Buonicontro, Dalila S.,Demuner, Antonio J.,Fonseca, Andressa R.,Gomes, Anni C. S.,Gondim, Jo??o P. E.,Pilau, Eduardo J.,Silva, Evandro
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p. 1805 - 1814
(2020/10/09)
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- Energy storage material based on 2,5-norbornadiene derivative and preparation method thereof
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The invention discloses an energy storage material based on a 2,5-norbornadiene derivative and a preparation method thereof. An esterification method is used for preparing an ortho grafted bisazo benzene 2,5-norbornadiene derivative; two azobenzene groups are introduced at 2,5-norbornadiene in an ortho manner, so that norbornadiene is obviously subjected to Einstein shift; the photon yield is effectively improved. 2,5-norbornadiene and the azobenzene groups are combined, so that the heat storage energy density can be effectively improved; the storage energy is increased. The material has excellent optical performance and is hopeful to be applied in the fields of light and heat conversion and energy storage.
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Paragraph 0036-0038; 0041-0043; 0046-0048
(2018/12/13)
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- Synthesis of novel chiral bisoxazoline ligands with a norbornadiene backbone: Use in the copper-catalyzed enantioselective Henry reaction
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Novel chiral bisoxazoline ligands based on norbornadiene were synthesized and used for the asymmetric Henry reaction. Various aromatic aldehydes were converted into chiral β -nitro alcohols with high yields and moderate to acceptable enantioselectivities
- Deliku?, Rabia,?akir, Emine,Demirel, Nadir,Balci, Metin,Karata?, Betül
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p. 248 - 261
(2016/05/24)
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- DEUTERATED 5-HT1A RECEPTOR AGONISTS
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The present invention relates to new deuterated derivatives of serotonin 5-HT1A receptor agonists of formula 1 and in particular to compositions and methods for therapeutic use.
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Paragraph 0369-0370
(2013/11/19)
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- DEUTERATED TANDOSPIRONE DERIVATIVES AS 5-HT1A RECEPTOR AGONISTS
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The present invention relates to new deuterated derivatives of serotonin 5-HT1A receptor agonists of formula 1 and in particular to compositions and methods for therapeutic use.
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Page/Page column 108; 109
(2012/02/15)
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- Mild and efficient boronic acid catalysis of Diels-Alder cycloadditions to 2-alkynoic acids
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The concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied to the Diels-Alder cycloaddition between 2-alkynoic acids as dienophiles and various dienes. These [4+2] cycloadditions produce cyclohexadienyl carboxylic acids, which can be oxidized in situ to produce polysubstituted aromatic carboxylic acids. The boronic acid catalyst is suspected to provide activation by a LUMO-lowering effect of the unsaturated carboxylic acid likely via a covalent, monoacylated hemiboronic ester intermediate.
- Zheng, Hongchao,Hall, Dennis G.
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supporting information; experimental part
p. 3561 - 3564
(2010/08/07)
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- SYNTHESIS OF HALF ESTERS
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A method for hydrolyzing an ester is provided. In accordance with the method, a compound A is provided which has first and second ester moieties. The compound is reacted in a liquid medium with a base having the formula MaXb,such that the first ester moiety is converted to a carboxyl moiety and the second ester moiety remains, wherein the ratio [Xk-]:[A] in the liquid medium is no greater than 1.6, and wherein k > 0.
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Page/Page column 29
(2009/01/24)
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- Factors influencing anion binding stoichiometry: The subtle influence of electronic effects
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Six new, charge-neutral norbornene-based receptors 1a,1b-3a,3b were prepared, and their ability to interact with simple anions in DMSO was investigated using 1H NMR and UV/Vis spectroscopy. Binding of dihydrogenphosphate by the six receptors ap
- Lowe, Adam J.,Dyson, Gail A.,Pfeffer, Frederick M.
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experimental part
p. 1559 - 1567
(2009/04/11)
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- Towards the cis-bromination of double bonds
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The bromination of olefins yielding a trans-1,2-dibromo-product was studied. Reagents were proposed to brominate the double bonds of cis-olefins mildly and stereospecifically. Reagents delivering two bromine atoms to the same side of olefins through a cyclic six-membered transition state were studied.
- Carman,Derbyshire,Hansford,Kadirvelraj,Robinson
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p. 117 - 126
(2007/10/03)
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- Novel photo-responsive organic spin systems: Preparation and properties of norbornadienes and spiropyrans with TEMPO radical substituents
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Several photo-responsive norbornadiene as well as spiropyran derivatives with TEMPO radical substituents were prepared and their light-induced structural changes to the corresponding quadricyclanes or merocyanine dyes and reverse reactions to the starting materials were investigated. While the intermolecular magnetic interactions tend to be preserved in norbornadiene-quadricyclane systems in spite of the differences of their Weiss temperatures, a switching of the intermolecular magnetic interactions was observed in the spiropyran-merocyanine systems.
- Nakatsuji, Shin'ichi,Ogawa, Yuya,Takeuchi, Soichi,Akutsu, Hiroki,Yamada, Jun-Ichi,Naito, Akira,Sudo, Kyoko,Yasuoka, Noritake
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p. 1969 - 1975
(2007/10/03)
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- The Pyrolysis of Butatrienone Precursors: 3,4-Diazatricyclo2,6>deca-3,8-diene-endo-cis-2,6-dicarboxylic Anhydride and its 5,5-Diphenyl Derivative
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Flash vacuum pyrolysis of the title anhydride (4) gave a poor yield of butatrienone, detected by argon matrix isolation infrared spectroscopy.Similar pyrolysis of the 5,5-diphenyl derivative (8) failed to give diphenylbutatrienone: the red product (16) is
- Anderson, Mark R.,Brown, Roger F. C.,Browne, Neil R.,Eastwood, Frank W.,Fallon, Gary D.,et al.
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p. 549 - 560
(2007/10/02)
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- Silver(I)-Catalyzed Isomerization of Water-Soluble Quadricyclanes
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In aqueous ammonia, silver(I)-catalyzed isomerization of quadricyclanes to norbornadienes was investigated.The catalytic action of silver(I) perchlorate induced rapid and clean isomerization of water-soluble quadricyclanes 1b-g to the corresponding norbornadienes 2b-g even at room temperature.In the isomerization, the silver(I) catalyst might attack 1 from the five-membered ring, which was different from the directions observed in the cobalt(II)-porphyryn- and rhodium(I)-catalyzed reactions.The present reactions proceed via the formation of the cationic species and the successive cleavage of the highly strained cyclopropane ring of 1 to give 2.
- Maruyama, Kazuhiro,Tamiaki, Hitoshi
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p. 3967 - 3970
(2007/10/02)
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