90-47-1Relevant articles and documents
Sodium Trimethylsilanethiolate in Novel Cyclizations for Synthesis of Aromatic Heterotricyclic Compounds
Lai, Long-Li,Lin, Pen-Yuan,Huang, Wen-Hong,Shiao, Min-Jen,Hwu, Jih Ru
, p. 3545 - 3546 (1994)
A new method was developed for synthesis of aromatic heterotricyclic compounds in 50-64percent yields from diaryls bearing a functionality including OMe, COOMe, and CN, and a leaving group (i.e., F and OMe) by use of Me3SiSNa in 1,3-dimethyl-2-imidazolidinone at 120-150 deg C.
New strategies for the synthesis and functionalization of tetrahydroxanthones
Turner, Penelope A.,Samiullah,Geden, Joanna V.,White, Alexander,Clarkson, Guy J.,Shipman, Michael
, p. 9433 - 9438 (2015)
Two strategies for the functionalization of simple tetrahydroxanthones (THX) on either of the carbocyclic rings are reported. By application of palladium catalysis, concomitant assembly of this heterocyclic scaffold with controlled introduction of substituents on the aromatic ring at C-5, C-6 or C-7 can be achieved. Variation in the nature of the added carbon fragment (aryl, alkenyl and alkynyl) is explored through use of different cross-coupling partners. Separately, functionalization at C-4 of the saturated carbocyclic ring is demonstrated through use of the extended enolate derived from 1-hydroxytetrahydroxanthone.
A new method for the preparation of 2,3-cycloalkeno-5,6-cycloalkeno-4H-pyran-4-ones
Xu, Fan,Cao, Xueqin,Cao, Zhengbai,Zou, Lei
, p. 10257 - 10261 (2000)
Several 2,3-cycloalkeno-5,6-cycloalkeno-4H-pyran-4-ones, such as 2,3,5,6-bicyclopenteno-4H-pyran-4-one and 1,2-dihydronaphtho[3,4-b]cyclopenteno[1,2-e]-4H-pyran-4-one, were synthesized conveniently by the reaction of a cyclic ketone enamine and diacylchloride. This reaction allows a new method for preparation of these compounds, which may be the precursors for the synthesis of some useful heterocycles. (C) 2000 Elsevier Science Ltd.
Multicomponent Reaction of Phosphines, Benzynes, and CO2: Facile Synthesis of Stable Zwitterionic Phosphonium Inner Salts
Xie, Pei,Yang, Shoushan,Guo, Yuyu,Cai, Zhihua,Dai, Bin,He, Lin
, p. 8872 - 8880 (2020)
The first synthesis of benzyne-derived stable zwitterions is reported. Benzynes generated in situ from 2-(trimethylsilyl)aryl triflates undergo a multicomponent reaction with phosphines and CO2 to produce the stable 1,5-zwitterionic species in moderate to excellent isolated yields, which provides a novel method for the preparation of phosphonium inner salts under mild and transition-metal-free conditions.
Reaction of thioketones with (R)-2-vinyloxirane: Regio- and stereoselective formation of (sS)-4-vinyl-1,3-oxathiolanes
Fedorov, Alexey,Fu, Changchun,Linden, Anthony,Heimgartner, Heinz
, p. 1613 - 1619 (2005)
The reactions of 4,4′-dimethoxythiobenzophenone (1), 9H-xanthene-9-thione (2), and adamantane-2-thlone (3) with (R)-2-vinyloxirane [(R)-6] in the presence of SiO2 in anhydrous CH2Cl 2 at 0°C or room temperature afforded th
Photoionization of xanthone via its triplet state or via its radical anion
Goez, Martin,Hussein, Belal Hussein Mohammed
, p. 5490 - 5497 (2004)
The photoionization of xanthone in methanol-water by light of wavelength 308, 355 and 532 nm was investigated by single-pulse and two-pulse laser-flash photolysis with optical detection of the hydrated electron and the ketone-based intermediates. Kinetic constants and quantum yields were obtained from the intensity dependences of the concentrations. In the absence of an electron donor, the mechanism is sequential. A first photon produces the triplet state, which is then ionized by a second photon with a quantum yield φion of 8 × 10-3 at both 308 and 355 nm; at 532 nm photoionization is undetectable (φion -6). When an electron donor (triethylamine or DABCO) is added in large excess, excitation of the ketone and quenching are followed by photoionization of the radical anion X.-. The latter regenerates the starting carbonyl compound, so in effect the donor is ionized by a catalytic cycle. The competition of both ionization pathways was studied quantitatively by varying the donor concentration. The ionization of X.- is monophotonic at 308 and 355 nm with a wavelength-independent quantum yield of 7 × 10-2. A biphotonic ionization was found at 532 nm; φion of the excited radical anion must be larger than 5 × 10-5. At that wavelength, nonabsorbing products are also formed with a quantum yield that is higher than φion by a factor of 3.2. The consistently lower quantum yields of photoionization in the absence of a donor were explained by reverse intersystem crossing of the upper excited triplet states as an efficient deactivation channel that is not accessible to the excited radical anions.
Synthesis of Xanthones by Palladium-Catalyzed Tandem Carbonylation/C–H Activation via 2-Iodo Diaryl Ethers
Ma, Rui-Yue,Chen, Ya-Fang,Wang, Jun-Ru,Du, Zhen-Ting
, p. 28 - 32 (2018)
The ring closure of 2-iodo diaryl ether in the presence of a palladium catalyst to xanthone under carbon monoxide atmosphere is studied. A series of xanthones could be successfully obtained through this protocol, with Pd(OAc)2 as the catalyst, P(Cy)3 as ligand, PivONa.H2O as base, and PivOH and tetrabutylamonium bromide as additives in DMSO, in moderate to good yields.
Intermolecular Electrochemical C(sp3)-H/N-H Cross-coupling of Xanthenes with N-alkoxyamides: Radical Pathway Mediated by Ferrocene as a Redox Catalyst
Lin, Meng-Ying,Xu, Kun,Jiang, Yang-Ye,Liu, Yong-Guo,Sun, Bao-Guo,Zeng, Cheng-Chu
, p. 1665 - 1672 (2018)
Efficient intermolecular dehydrogenative cross-coupling of N-alkyloxyamides with xanthenes is reported. The protocol is carried out in an undivided cell under constant current conditions employing simple, cheap and readily available ferrocene (Fc) as a redox catalyst. Cyclic voltammetry and control experiments disclosed that the dehydrogenative cross-coupling reaction may proceed via an amidyl radical. (Figure presented.).
1,3-Dichloro-tetra-n-butyl-distannoxane: A new application for catalyzing the direct substitution of 9H-xanthen-9-ol at room temperature
Liu, Ling-Yan,Zhang, Yan,Huang, Kai-Meng,Chang, Wei-Xing,Li, Jing
, p. 9 - 15 (2012)
1,3-Dichloro-tetra-n-butyl-distannoxane was firstly used to catalyze the direct substitution of 9H-xanthen-9-ol with indoles at room temperature to afford a class of 3-(9H-xanthen-9-yl)-1H-indole derivatives in good to excellent isolating yield. Moreover, other nucleophiles (such as diketone and pyrrole) could also proceed smoothly in this methodology. Copyright
A highly efficient thiourea catalyzed dehydrative nucleophilic substitution reaction of 3-substituted oxindoles with xanthydrols
Chen, Long,Zhu, Feng,Wang, Cui-Hong,Zhou, Jian
, p. 19880 - 19884 (2013)
We report a highly efficient thiourea catalyzed dehydrative nucleophilic substitution reaction. The Schreiner's thiourea catalyst A1 catalyzed the alkylation of 3-substituted oxindoles with xanthydrols well, to furnish quaternary oxindoles in high yield. The ESI-MS analysis confirms the interaction of 3-substituted oxindole 1 with the thiourea, which might facilitate the oxindole-hydroxindole tautomerization for the alkylation. The Royal Society of Chemistry 2013.
