1200-89-1Relevant academic research and scientific papers
UV PhotoVap: Demonstrating How a Simple and Versatile Reactor Based on a Conventional Rotary Evaporator Can Be Used for UV Photochemistry
Clark, Charlotte A.,Lee, Darren S.,Pickering, Stephen J.,Poliakoff, Martyn,George, Michael W.
, p. 595 - 599 (2018)
We report the use of a simple rotary evaporator as a semi-continuous UV photochemical reactor. By generation of a thin film from the rotation of a flask, better light penetration is achieved, and in this work we used high-power Hg lamps to enable the direct irradiation of molecules with UV light. The intramolecular [2 + 2] photocycloaddition of Cookson's dione and the intermolecular [2 + 2] photocycloaddition of maleimide with 1-hexyne were used as test reactions to examine the effectiveness of this reactor. High productivities, equivalent to 210 g h-1, were obtained for the simple intramolecular reaction, demonstrating the scalability of the reactor. The effects of flask size, reaction mixture volume, and use of borosilicate or quartz glassware were also investigated.
First synthesis of 9,10-dimethoxy-2-methyl-1,4-anthraquinone: A naturally occurring unusual anthraquinone
Mal, Dipakranjan,Ray, Sutapa
, p. 3014 - 3020 (2008)
The synthesis of 9,10-dimethoxy-2-methyl-1,4-anthraquinone, an unusual quinone, was achieved in five steps from p-benzoquinone. A Kochi-Anderson radical methylation features as the key step in the synthesis. The chemistry of a cyclopropa-1,4-anthracenedio
A Crystalline Ready-to-Use Form of Cyclopentadiene
Krupp, Felix,He, Shiliang,Frey, Wolfgang,Richert, Clemens
, p. 1707 - 1710 (2018)
Cyclopentadiene (Cpd) is widely used as a starting material in organic and inorganic chemistry. In neat form, Cpd dimerizes, making it necessary to distill it prior to use to obtain fully reactive material. We have screened three different tetraphenyladamantane octaethers for their ability to act as encapsulating organic crystal (EnOC) hosts for Cpd. To this end, we also synthesized 1,3,5,7-tetrakis(3,5-dimethoxyphenyl)adamantane, a new octaether, dubbed iso -TDA. Only one of the octaethers was found to produce inclusion complexes with Cpd in the crystalline state. The encapsulated diene was stable for one month and showed full reactivity in a series of different synthetic transformations.
Unexpected regioselectivity observed in the bromination and epoxidation reactions of p-benzoquinone-fused norbornadiene: An experimental and computational study
Essiz, Selcuk,Dalkilic, Erdin,Sari, Ozlem,Dastan, Arif,Balci, Metin
, p. 1640 - 1649 (2017)
The bromination reaction of p-benzoquinone-fused norbornadiene was studied at various temperatures (?78,??50, 0, 25, and 77?°C). At room temperature, the double bonds of the p-benzoquinone units were mainly brominated. The double bond of the norbornene unit also underwent a bromination reaction in a yield of only 2%. However, the reaction at??78?°C resulted in the formation of products derived from the attack of bromine on the norbornene double bond with higher charge density. In contrast to the bromination reaction, the epoxidation reaction of the same compound with m-chloroperbenzoic acid and dimethyldioxirane exclusively resulted in the formation of products derived from the addition to the double bond of norbornadiene. The regioselectivity observed was investigated and the results were supported by theoretical calculations.
Soluble cycloannulated tetroxa[8]circulane derivatives: Synthesis, optical and electrochemical properties, and generation of their robust cation-radical salts
Rathore, Rajendra,Abdelwahed, Sameh H.
, p. 5267 - 5270 (2004)
Syntheses of soluble bicycloalkane-annulated tetraoxa[8]circulane derivatives via Lewis acid-catalyzed tetramerization of readily available cycloannulated benzoquinons is described. The ready availability of the soluble circulane derivatives allows the evaluation of their optical and electrochemical properties. These circulanes form stable (isolable) cation-radical salts upon 1-electron oxidation using antimony pentachloride and various aromatic oxidants.
Lewis acid catalyst system for Diels–Alder reaction
Kalepu, Rishir,Mishra, Satyendra
, (2020)
Abstract: Ca(OTf)2/Bu4NPF6 catalytic system has been illustrated for the synthesis of Diels–Alder adduct for the first time. This procedure tolerates substrate diversity and delivers high yield. Use of environmentally benign catalyst, high yields and substrate diversity are the highlight of the existing method. Graphic Abstract: Ca(OTf)2, along with n-Bu4NPF6 as the co-catalyst, is shown to be an effective Lewis acidic catalyst system for the Diels–Alder reaction. Apart from being sustainable and efficient, this procedure is robust and products are obtained in near-quantitative yields.[Figure not available: see fulltext.].
Triquinane scaffolds: Shape and geometry as a function of saturation and bridgehead groups
Young, Lois-May,Zeller, Matthias,Geldenhuys, Werner J.,Malan, Sarel F.,Van Der Schyf, Cornelis J.
, p. 86 - 94 (2013)
Polycyclic hydrocarbon compounds, also known as "cage compounds", are of interest in drug discovery due to their versatility as scaffolds. Derivatives of both pentacycloundecane-dione and triquinane-dione have been the focus of numerous investigations as multifunctional neuroprotective drugs where these compounds were used as novel drug scaffolds with the ability to cross the blood brain barrier. Here we present the synthesis, characterization and single crystal X-ray analysis for two triquinane synthons; tricyclo[6.3.0.0 2,6]undecane-4,9-diene-3,11-dione (compound 5 crystallizes in the monoclinic system, unit cell parameters are: a = 6.5876 (12) ?, b = 10.4204 (19) ?, c = 12.074 (2) ?; V = 825.4 (3) ?3 and Z = 4) and tricyclo[6.3.0.02,6]undecane-3,11-dione (compound 6 crystallizes in monoclinic system, unit cell parameters are: a = 7.5992 (7) ?, b = 10.7294 (10) ?, c = 10.8664 (10) ?; V = 884.04 (14) ?3 and Z = 4); as well as a triquinane derivative, N-(3-methoxybenzyl)-3,11-azatricyclo[6.3.0.02,6]undecane (compound 11 crystallizes in triclinic system, unit cell parameters are: a = 7.6714 (7) ?, b = 9.0100 (9) ?, c = 11.2539 (11) ?; V = 745.78 (12) ?3 and Z = 2). The size and geometrical conformation of the triquinane scaffolds were compared to tetra and pentacycloundecanes, revealing that tricyclo[6.3.0.02,6]undecane-3,11-dione experiences strain relief resulting in greater flexibility, a more asymmetric molecular shape and larger surface area. However, with the introduction of the aza-bridge in N-(3-methoxybenzyl)-3,11-azatricyclo[6.3.0.02,6]undecane, much of the flexibility and asymmetry is lost again. We also discuss the rearrangement mechanism for the observed retro cycloaddition and reversion, and utilized density functional theory calculations to discuss the photocyclization mechanism of this unique [2 + 2] Diels-Alder system.
The Rates of a Diels-Alder Reaction in Liquid and Supercritical Carbon Dioxide
Isaacs, Neil S.,Keating, Nicholas
, p. 876 - 877 (1992)
Kinetic measurements on the Diels-Alder reaction between p-benzoquinone and cyclopenta-1,3-diene have been carried out in carbon dioxide as a medium between 25 and 40 deg C; the reaction effectively occurs throughout liquid and supercritical ranges with no discontinuity and rates are about 20percent greater than those in diethyl ether.
Design, synthesis and evaluation of pentacycloundecane and hexacycloundecane propargylamine derivatives as multifunctional neuroprotective agents
Zindo, Frank T.,Malan, Sarel F.,Omoruyi, Sylvester I.,Enogieru, Adaze B.,Ekpo, Okobi E.,Joubert, Jacques
supporting information, p. 83 - 94 (2018/12/04)
The multifactorial pathophysiology of neurodegenerative disorders remains one of the main challenges in the design of a single molecule that may ultimately prevent the progression of these disorders in affected patients. In this article, we report on twelve novel polycyclic amine cage derivatives, synthesized with or without a propargylamine function, designed to possess inherent multifunctional neuroprotective activity. The MTT cytotoxicity assay results showed the SH-SY5Y human neuroblastoma cells to be viable with the twelve compounds, particularly at concentrations less than 10 μM. The compounds also showed significant neuroprotective activity, ranging from 31% to 61% at 1 μM, when assayed on SH-SY5Y human neuroblastoma cells in which neurodegeneration was induced by MPP+. Calcium regulation assays conducted on the same cell line showed the compounds to be significant VGCC blockers with activity ranging from 26.6% to 51.3% at 10 μM; as well as significant NMDAr antagonists with compound 5 showing the best activity of 88.3% at 10 μM. When assayed on human MAO isoenzymes, most of the compounds showed significant inhibitory activity, with compound 5 showing the best activity (MAO-B: IC50 = 1.70 μM). Generally, the compounds were about 3–52 times more selective to the MAO-B isoenzyme than the MAO-A isoenzyme. Based on the time-dependency studies conducted, the compounds can be defined as reversible MAO inhibitors. Several structure activity relationships were derived from the various assays conducted, and the compounds’ possible putative binding modes within the MAO-B enzyme cavity were assessed in silico.
Underwater diene addition reaction synthesizing method and application thereof in synthesizing of double-cage spiro hydrocarbon PCUD
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Paragraph 0047; 0052-0055, (2019/09/17)
The invention provides an underwater diene addition reaction synthesizing method and application thereof in synthesizing of double-cage spiro hydrocarbon PCUD. The synthesizing method is characterizedin that p-benzoquinone and cyclic conjugate diolefins are treated as raw materials, and water is treated as a dispersant, and on that basis, Diels-Alder addition reaction is carried out. According tothe method, pure water is treated as a medium in the reaction; and the reaction post-treatment is simple, and easy to carry out; the energy consumption is low; and the yield is high.
