- Ultraviolet-light-induced aerobic oxidation of benzylic C(sp3)-H of alkylarenes under catalyst- and additive-free conditions
-
A mild and efficient system has been discovered for the synthesis of α-aryl carbonyl compounds via oxidation of benzylic C–H to C[dbnd]O bonds. This ultraviolet-light-mediated oxygenation reaction exhibited excellent substrate scope including various xanthenes, thioxanthenes and 9, 10-dihydroacridines and afforded the corresponding ketones with good to excellent yields under catalyst- and additive-free conditions at room temperature.
- Zhou, Jiacheng,Li, Meichao,Li, Tianci,Li, Chunmei,Hu, Xinquan,Jin, Liqun,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu
-
-
- Ultraviolet light promoted synthesis method of xanthone compounds
-
The invention discloses an ultraviolet light promoted synthesis method of a xanthone compound. The method comprises the steps: by taking a xanthene compound as a reaction substrate and oxygen in air as an oxidant, carrying out a reaction on the reaction substrate in an organic solvent at normal temperature under the condition of 380-385 nm ultraviolet irradiation, and after the reaction is finished, carrying out separation treatment to obtain the xanthone compound. According to the synthesis method disclosed by the invention, a traditional heating reaction is replaced by an illumination reaction, so that energy sources can be saved; no catalyst is used.
- -
-
Paragraph 0037; 0038
(2020/05/05)
-
- A Green Nanopalladium-Supported Catalyst for the Microwave-Assisted Direct Synthesis of Xanthones
-
We report an efficient, selective, rapid and eco-friendly protocol for the one-step synthesis of a small xanthone library via an intermolecular catalytic coupling from readily available salicylaldehydes and 1,2-dihaloarenes under ligand-free conditions. To achieve this advantageous direct annulation, we used a novel recoverable palladium nanocatalyst supported on a green biochar under microwave irradiation. Unlike other existing palladium-based approaches, our synthetic strategy showed a greater operational simplicity, drastic reduction in reaction times, and an excellent tolerance to diverse functional groups. The reaction proceeds in very good yields and with high regioselectivity. The novel heterogeneous catalyst can be recycled and reused up to four times without significant loss of activity.
- Diez, Alejandra S.,Gerbino, Darío C.,Mendioroz, Pamela,Steingruber, H. Sebastián
-
supporting information
p. 619 - 628
(2020/02/13)
-
- Ceric Ammonium Sulfate (CAS) Mediated Oxidations of Benzophenones Possessing a Phenolic Substituent for the Synthesis of Xanthones and Related Products
-
Work previously published by our group described novel methodology for the synthesis of xanthones and related products from phenolic benzophenones in a reaction mediated by ceric ammonium sulfate (CAS). In this paper we further explore this novel reaction by subjecting an additional set of phenolic benzophenones to CAS to afford a range of compounds, including xanthones, 9H-xanthen-2,9(4aH)-diones, 3H-spiro[benzofuran-2,1′-cyclohexa[2,5]diene]-3,4′-diones, and biaryl compounds. A comparison of these reactions with the more commonly used oxidant ceric ammonium nitrate (CAN) was also conducted. Based on these results, greater insight into the reaction mechanism has been gained. In addition, the conversion of the synthesized xanthen-2,9(4aH)-diones to xanthones by treatment with sodium dithionite is described.
- Dam, Jean,Bode, Moira L.,De Koning, Charles B.
-
p. 150 - 160
(2019/01/10)
-
- Visible-light induced enhancement in the multi-catalytic activity of sulfated carbon dots for aerobic carbon-carbon bond formation
-
The development of carbonaceous materials as metal-free catalysts integrating different types of catalysis in a single system represents a significant advance in cascade/tandem organic synthesis. Zero-dimensional carbon dots with tuneable optical properties and easily modifiable surface functionalities can be harnessed as a carbocatalyst for merging photooxidation and acid-catalyzed reactions in one pot. Herein, we explore carbon dots decorated with hydrogen sulfate groups as a photocatalyst for the dehydrogenative cross-coupling of xanthenes with ketones, arenes and 1,3-dicarbonyl compounds that showed high efficiency and selectivity under visible-light irradiation. The sulphated carbon dots demonstrate dual catalytic properties, wherein they induced the rapid photooxidation of xanthenes in the presence of molecular oxygen to form a hydroperoxy intermediate followed by coupling of nucleophiles catalysed by the acidic surface functional groups. The methodology represents an operationally simple pathway for the generation of C-C coupling products in a short reaction time with wide substrate scopes under mild conditions. The catalyst is easily separable and can be reused over multiple cycles with good efficiency.
- Sarma, Daisy,Majumdar, Biju,Sarma, Tridib K.
-
p. 6717 - 6726
(2019/12/26)
-
- Visible-Light-Induced Aerobic Oxidation of Benzylic C(sp 3)-H of Alkylarenes Promoted by DDQ, tert -Butyl Nitrite, and Acetic Acid
-
A visible-light photocatalytic aerobic oxidation of benzylic C(sp 3)-H bonds proceeded in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tert -butyl nitrite, and acetic acid. Advantages of this aerobic oxidation method include its relatively mild conditions, the use of visible-light irradiation instead of conventional thermal methods, the use of a low catalyst loading, and the ability to oxidize a range of alkylarenes, including xanthenes, thioxanthenes, and 9,10-dihydroacridines, to the corresponding ketones in excellent yields.
- Pan, Decheng,Wang, Yiqing,Li, Meichao,Hu, Xinquan,Sun, Nan,Jin, Liqun,Hu, Baoxiang,Shen, Zhenlu
-
p. 218 - 224
(2019/01/14)
-
- Method for catalytic oxidization synthesis of anthone compound
-
The invention discloses a method for catalytic oxidation synthesis of an anthone compound. The method is carried out according to the following steps: adding an anthene compound, Fe(NO3)3*9H2O and a fluorine-containing inorganic salt into an acetonitrile solvent, and performing a reaction for 2-12h at 75-85 DEG C under a normal pressure oxygen condition to obtain the anthone compound, wherein the mass ratio of the reaction substrate namely the anthone compound, Fe(NO3)3*9H2O and the fluorine-containing inorganic salt is 100:(8-15):(15-30), and after the completion of the reaction, the anthone compound can be obtained by adopting conventional column separation purification. The method provided by the invention is simple, convenient and safe to operate, and has the following beneficial effects: A) clean oxygen is used as an oxidant in the method, so that the environmental cost is greatly reduced; and B) Fe(NO3)3*9H2O is used as a catalyst in the method, so that the cost is low.
- -
-
Paragraph 0037
(2017/07/21)
-
- FeCl3 and ether mediated direct intramolecular acylation of esters and their application in efficient preparation of xanthone and chromone derivatives
-
The direct intramolecular acylation of esters was developed by using the combined system of FeCl3 with Cl2CHOCH3. This unique cooperative system offered a new and efficient approach to biologically important xanthone and chromone derivatives with regioselectivity. Examples were reported, and control experiments were carried out to examine the effect of the benzyl esters and Cl2CHOCH3.
- Jiang, Neng,Li, Su-Yi,Xie, Sai-Sai,Yao, Hequan,Sun, Hongbin,Wang, Xiao-Bing,Kong, Ling-Yi
-
supporting information
p. 63632 - 63641
(2015/02/19)
-
- One-step synthesis of xanthones catalyzed by a highly efficient copper-based magnetically recoverable nanocatalyst
-
A versatile and highly efficient strategy to construct a xanthone skeleton via a ligand-free intermolecular catalytic coupling of 2-substituted benzaldehydes and a wide range of phenols has been developed. For this purpose, a novel and magnetically recoverable catalyst consisting of copper nanoparticles on nanosized silica coated maghemite is presented. The reaction proceeds smoothly with easy recovery and reuse of the catalyst. The methodology is compatible with various functional groups and provides an attractive protocol for the generation of a small library of xanthones in very good yield.
- Menendez, Cintia A.,Nador, Fabiana,Radivoy, Gabriel,Gerbino, Dario C.
-
supporting information
p. 2846 - 2849
(2014/06/23)
-
- Metal-free oxidative coupling: Xanthone formation via direct annulation of 2-aryloxybenzaldehyde using tetrabutylammonium bromide as a promoter in aqueous medium
-
A metal-free intramolecular annulation of 2-aryloxybenzaldehydes to xanthones is disclosed, which proceeds through the direct oxidative coupling of an aldehyde C-H bond and aromatic C-H bonds using tetrabutylammonium bromide (TBAB) as a promoter in aqueous medium. This strategy works smoothly in the presence of both electron-donating and electron-withdrawing groups, and displays good tolerance towards catalytically reactive substituents, thus promising further functionalizations of xanthone products.
- Rao, Honghua,Ma, Xinyi,Liu, Qianzi,Li, Zhongfeng,Cao, Shengli,Li, Chao-Jun
-
supporting information
p. 2191 - 2196
(2013/10/01)
-
- Hydrophobicity constants for several xanthones and flavones
-
The octanol-water distribution of several xanthones and flavones was studied. Their hydrophobicity constants (log P) were determined. The lipophilicity constants (π) of the substituents were calculated. The relationship between the structure and hydrophobicity constants of the gamma-pyrone derivatives was found.
- Pogodaeva,Medvedeva,Sukhov,Shishmareva
-
experimental part
p. 38 - 42
(2011/07/06)
-
- One-step preparation of xanthones via Pd-catalyzed annulation of 1,2-dibromoarenes and salicylaldehydes
-
A one-step preparation of xanthones via Pd-catalyzed annulation of 1,2-dibromoarenes and salicylaldehydes was developed.
- Wang, Sizhuo,Xie, Kai,Tan, Ze,An, Xiangyu,Zhou, Xingjian,Guo, Can-Cheng,Peng, Zhihong
-
supporting information; experimental part
p. 6469 - 6471
(2010/03/04)
-
- Reaction of benzyne with salicylaldehydes: General synthesis of xanthenes, xanthones, and xanthols
-
The reaction of salicylaldehydes with benzyne prepared from o-trimethylsilyphenyl triflate and CsF gave xanthenes and xanthones. When the reaction was carried out under basic conditions, 9-hydroxyxanthenes (xanthols) were obtained in good yields.
- Okuma, Kentaro,Nojima, Akiko,Matsunaga, Nahoko,Shioji, Kosei
-
supporting information; experimental part
p. 169 - 171
(2009/06/20)
-
- Synthesis of xanthones, thioxanthones, and acridones by the coupling of arynes and substituted benzoates
-
The reaction of silylaryl triflates, CsF, and ortho-heteroatom-substituted benzoates affords a general and efficient way to prepare biologically interesting xanthones, thioxanthones, and acridones. This chemistry presumably proceeds by a tandem intermolecular nucleophilic coupling of the benzoate with an aryne and a subsequent intramolecular electrophilic cyclization.
- Zhao, Jian,Larock, Richard C.
-
p. 583 - 588
(2007/10/03)
-
- TRICYCLIC OPIOID MODULATORS
-
The invention is directed to compounds of Formula (I) useful as delta and mu opioid receptor modulators. Pharmaceutical and veterinary compositions and methods of treating mild to severe pain and various diseases using compounds of the invention are also
- -
-
Page/Page column 18-19
(2008/06/13)
-
- Synthesis and photochromic behavior of novel annelated 2H-chromenes derived from hydroxy-9H-xanthen-9-ones
-
The synthesis of four novel pyrano-xanthenones derived from hydroxy-9H-xanthen-9-ones is described, and their photochromic properties in solution are reported. All compounds synthesized exhibit a good colorability, making them good potential dyes. The presence of the chromone system fused in the 78-position seems to lead to more stabilized colored forms.
- Coelho, Paulo J.,Carvalho, Luis M.,Silva, Jose C.,Oliveira-Campos, Ana M.F.,Samat, Andre,Guglielmetti, Robert
-
p. 117 - 123
(2007/10/03)
-
- A Complex Induced Proximity Effect in the Anionic Fries Rearrangement of o-Iodophenyl Benzoates: Synthesis of Dihydro-O-methylsterigmatocystin and Other Xanthones
-
The success of an anionic Fries rearrangement, used to synthesise dihydro-O-methylsterigmatocystin and other xanthones, is dependent on the presence of a remote methoxyl substituent.
- Horne, Stephen,Rodrigo, Russell
-
p. 4520 - 4522
(2007/10/02)
-
- POTENTIAL ANTIDEPRESSANTS: 4-(AMINOALKOXY)THIOXANTHONES
-
Four different approaches were used for preparing a series of the title compounds.Reactions of the sodium salt of 4-hydroxythioxanthone (V) with dimethylaminoalkyl chlorides gave the ethers VI and VII.Partial demethylation of VII via the carbamate IX afforded the secondary amine VIII.Reactions of the 4-bromobutoxy compound XI with amines resulted in II, XII, and XIII.Reaction of V with 1-chloro-2,3-epoxypropane and the following treatment of the resulting XIV with 2-propanamine gave the amino alcohol XV.The xanthone III was obtained via XVIII similarly like II.Theproducts, especially II and III are cyclic analogues of the antidepressant and cerebral activator "bifemelane" (I) but they do not exhibit the pharmacological profile of antidepressants.
- Cervena, Irena,Holubek, Jiri,Svatek, Emil,Protiva, Miroslav
-
p. 1307 - 1316
(2007/10/02)
-
- Xanthones and Triterpenes of Mammea acuminata (Guttiferae)
-
2-Methoxyxanthone, 2-hydroxyxanthone, 4-hydroxyxanthone, 1-hydroxy-7-methoxyxanthone, 1,5-dihydroxyxanthone, 1,7-dihydroxyxanthone, 5-hydroxy-1-methoxyxanthone, 3-hydroxy-2-methoxyxanthone and a new natural product 2,6-dihydroxyxanthone have been isolated from the timber extractives of Mammea acuminata.A biogenetic pathway for the formation of xanthones is proposed.The occurence of the triterpenes glutinol and glutinone is reported for the first time from Guttiferae.
- Bandaranayake, Wickramasinghe M.,Karunanayake, Subadra,Sotheeswaran, Subramaniam,Sultanbawa, M. U. S.
-
p. 463 - 467
(2007/10/02)
-