954-07-4Relevant academic research and scientific papers
Reactivity of Stable Rotamers. XXXV. Diazotization of 2-(1,4-Dimethyl-9-triptycyl)-2-methylpropylamine Rotamers
Oki, Michinori,Taguchi, Yasushi,Miyasaka, Tsutomu,kitano, Mika,Toyota, Shinji,et al.
, p. 1485 - 1496 (1995)
The title amine rotamers were prepared from the corresponding carboxylic acids and were diazotized with isopentyl nitrite in the presence of acetic acid in benzene.The ap rotamer affords, as main products, olefins that are derived by deprotonation after rearrangement of the intervening carbocation and small amounts each of the corresponding acetate and a cyclized product, both of which are derived from the unrearranged cation.By contrast, the olefins a minor products and a cyclized product, which is formally derived by insertion of the intervening cation to a C-H bond of the 1-methyl group before rearrangement, is main in the case of the sc isomer.This cyclic product was synthesized independently.The yield of the corresponding acetate is increased to a considerable extent in the case of the sc relative to the ap.These results in the reaction of the sc are discussed in terms of stabilization of the intervening cation by the C-H bond.
Photochemical hydroxylation of 1-methyl-9,10-anthraquinones: Synthesis of 9′-hydroxyaloesaponarin II
Elkazaz, Salwa,Jones, Paul B.
, p. 412 - 416 (2010)
(Chemical Equation Presented) Photolysis of 1-methyl-9,10-anthraquinones in the presence of oxygen yields endoperoxides that can be reduced to produce 1-hydroxymethyl-9,10-anthraquinones. The reaction proceeds in a fashion similar to that of other o-alkylphenones which yield either a 1,4-diradical or a "photoenol" upon irradiation. Anthraquinones undergo photochemistry at a wavelength where the endoperoxide is transparent, allowing its isolation. A singlet oxygen quencher had no effect on the rate of formation of the endoperoxide. The photochemical hydroxylation has been used in a total synthesis of a naturally occurring polyketide, 9′-hydroxyaloesaponarin II.
Experimental and theoretical study of photoenolization mechanism for 1-methylanthraquinone
Gritsan, Nina P.,Khmelinski, Igor V.,Usov, Oleg M.
, p. 9615 - 9620 (1991)
Photoenolization of 1-methylanthraquinone (AQ) and its deuterated analogue (AQ-d6) has been studied by laser flash photolysis over a wide temperature range (120-340 K). Phototransfer of a H (or D) atom has been found to occur in both the singlet and triplet nπ* states. The temperature dependence of the efficiency of the phototransfer of H and D atoms in the 1nπ* state has been analyzed. Piperylene quenching of AQ and AQ-d6 triplet excited states has been studied. The rate constants of H- and D-atom phototransfer at room temperature have been estimated to be ca. 3 × 1010 s-1 and ca. 1010 s-1, respectively. Quantum-chemical calculations of potential energy surfaces and of electronic and geometrical structures of key intermediates have been performed by using the AMI technique. A triplet σ,π-biradical has been found to be the intermediate preceding the formation of 9-hydroxy-1,10-anthraquinone-1-methide (AQM). It has been revealed that thermal transformation of the enol AQM to the initial quinone AQ can occur as an intramolecular process via reverse transfer of a H atom, or as a second-order reaction. The latter appears to involve the transfer of two H (or D) atoms in a collisional complex of two AQM molecules. The dependence of the rate constants of the intramolecular thermal transfer of H and D atoms on temperature and solvent nature has been analyzed.
Eco-friendly organocatalyst- And reagent-controlled selective construction of diverse and multifunctionalized 2-hydroxybenzophenone frameworks for potent UV-A/B filters by cascade benzannulation
Akhtar, Muhammad Saeed,Inductivo Tamargo, Ramuel John,Kim, Sung Hong,Lee, Yong Rok,Thombal, Raju S.,Yang, Won-Guen
supporting information, p. 4523 - 4531 (2020/08/10)
The organocatalyst- and reagent-controlled highly selective synthesis of diversely functionalized novel 2-hydroxybenzophenone frameworks, such as 2-hydroxy-3′-formylbenzophenones, 7-(2′-hydroxybenzoyl)-2-naphthaldehydes, and 2-hydroxybenzophenones, under green conditions, for the development of potent UV-A/B filters is described. The organocatalyzed benzannulation reactions proceed individually via [3 + 3] cycloaddition for the synthesis of 2-hydroxy-3′-formylbenzophenones and [4 + 2] cycloaddition for 2-hydroxybenzophenones. With this methodology, an unprecedented double benzannulation allows one-pot construction of diverse 7-(2′-hydroxybenzoyl)-2-naphthaldehydes via [3 + 3 + 4] cycloaddition. This protocol features a broad substrate scope, high functional-group tolerance, and operational simplicity in an environmentally benign green solvent. The synthesized compounds are successfully utilized for further transformations and well characterized as potent UV-A/B filters.
Full Cleavage of C≡C Bond in Electron-Deficient Alkynes via Reaction with Ethylenediamine
Vasilevsky, Sergei F.,Davydova, Maria P.,Mamatyuk, Victor I.,Tsvetkov, Nikolay,Hughes, Audrey,Baranov, Denis S.,Alabugin, Igor V.
, p. 421 - 429 (2017/04/07)
Reaction of 1,2-diaminioethane (ethylenediamine) with electron-deficient alkynes leads to full scission of the C≡C bond even in the absence of a keto group directly attached to the alkyne. This process involves oxidation of one of the alkyne carbons into C2 of a 2-R-4,5-dihydroimidazole with the concomitant reduction of the other carbon to a methyl group. The sequence of Sonogashira coupling with the ethylenediamine-mediated fragmentation described in this work can be used for selective formal substitution of halogen in aryl halides by a methyl group or a 4,5-dihydroimidazol-2-yl moiety.
Synthesis method of anthraquinone derivatives and tetracenedione derivatives through benzannulation reaction
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Paragraph 0029-0030; 0043, (2017/08/09)
The present invention relates to a method for synthesizing anthraquinone derivatives and tetracene dione derivatives through a benzannulation reaction, which presents a novel synthesis method, capable of processing synthesis easily, conveniently, and efficiently under mild conditions by an organic catalyst. The synthesis method uses an L-proline catalyst which is nontoxic, economical and easily available, compared to conventional production methods, thereby providing the anthraquinone derivatives and the tetracene dione derivatives through the one-pot benzannulation reaction of an α, β-unsaturated aldehyde compound, various 1,4-naphthoquinone compounds or 1,4-anthracenedione compounds. Various forms of anthraquinone derivatives or tetracene dione derivatives prepared by the synthesis method can be widely used for synthesis of natural products, dyes, and pharmaceutical products.COPYRIGHT KIPO 2017
Organocatalyzed benzannulation for the construction of diverse anthraquinones and tetracenediones
Somai Magar, Krishna Bahadur,Xia, Likai,Lee, Yong Rok
supporting information, p. 8592 - 8595 (2015/05/20)
An efficient one-pot synthesis of anthraquinones and tetracenediones was achieved vial-proline catalyzed [4+2] cycloaddition of in situ generated azadiene from α,β-unsaturated aldehydes and 1,4-naphthoquinones or 1,4-anthracenedione in good to excellent yield. This protocol constitutes an unprecedented tandem benzannulation that allows one-pot construction of diverse anthraquinones and tetracenediones in the presence of organocatalysts. This methodology was applied successfully to the synthesis of naturally occurring molecules and photochemically interesting phenanthrenequinone derivatives.
Photoproducts of carminic acid formed by a composite from Manihot dulcis waste
Antonio-Cisneros, Cynthia M.,Dvila-Jimnez, Martn M.,Elizalde-Gonzlez, Mara P.,Garca-Daz, Esmeralda
, p. 725 - 732 (2015/01/09)
Carbon-TiO2 composites were obtained from carbonised Manihot dulcis waste and TiO2 using glycerol as an additive and thermally treating the composites at 800 °C. Furthermore, carbon was obtained from manihot to study the adsorption,
Photoproducts of carminic acid formed by a composite from Manihot dulcis waste
Antonio-Cisneros, Cynthia M.,Dávila-Jiménez, Martín M.,Elizalde-González, María P.,García-Díaz, Esmeralda
, p. 725 - 753 (2015/02/19)
Carbon-TiO2 composites were obtained from carbonised Manihot dulcis waste and TiO2 using glycerol as an additive and thermally treating the composites at 800°C. Furthermore, carbon was obtained from manihot to study the adsorption, desorption and photocatalysis of carminic acid on these materials. Carminic acid, a natural dye extracted from cochineal insects, is a pollutant produced by the food industry and handicrafts. Its photocatalysis was observed under different atmospheres, and kinetic curves were measured by both UV-Vis and HPLC for comparison, yielding interesting differences. The composite was capable of decomposing approximately 50% of the carminic acid under various conditions. The reaction was monitored by UV-Vis spectroscopy and LC-ESI-(Qq)-TOF-MS-DAD, enabling the identification of some intermediate species. The deleterious compound anthracene-9,10-dione was detected both in N2 and air atmospheres.
Highly strained dihydroanthraquinones: Oxidation versus elimination
Reynolds, John D.,Brinson, Robert G.,Day, Cynthia S.,Jones, Paul B.
, p. 2955 - 2959 (2007/10/03)
The chemistry of strained dihydroanthraquinones was investigated for the purpose of developing syntheses for highly strained anthraquinones. The reaction of (1,4-dihydro-9,10-dioxo-anthracen-1-yl)-acetates with triethylamine under aerobic conditions was found to be dependent on the degree of substitution on the acetate. Dihydroanthraquinones bearing dimethylacetates underwent elimination of enolate exclusively, while those without acetate substitution dehydrogenated as expected. Furthermore, oxidation of the cyclohexadiene ring using iodine failed due to a competitive iodolactonization reaction. The desired strained anthraquinones could be prepared, in low yield, by treatment of the resulting lactones with acidic ethanol.
