- Development of a Rhodium(II)-Catalyzed Chemoselective C(sp3)-H Oxygenation
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We report the first example of RhII-catalyzed chemoselective double C(sp3)-H oxygenation, which can directly transform various toluene derivatives into highly valuable aromatic aldehydes with great chemoselectivity and practicality. The critical combination of catalyst Rh(OAc)2, oxidant Selectfluor, and solvents of TFA/TFAA promises the successful delivery of the oxidation with satisfactory yields. A possible mechanism involving a unique carbene-Rh complex is proposed, and has been supported by both experiments and theoretical calculations.
- Lin, Yun,Zhu, Lei,Lan, Yu,Rao, Yu
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supporting information
p. 14937 - 14942
(2015/10/19)
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- Total synthesis, cytotoxic effects of damnacanthal, nordamnacanthal and related anthraquinone analogues
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Naturally occurring anthraquinones, damnacanthal (1) and nordamnacanthal (2) were synthesized with modified reaction steps and investigated for their cytotoxicity against the MCF-7 and K-562 cancer cell lines, respectively. Intermediate analogues 2-bromomethyl-1,3-dimethoxyanthraquinone (5, IC 50 = 5.70 ± 0.21 and 8.50 ± 1.18 μg/mL), 2-hydroxymethyl-1,3-dimethoxyanthraquinone (6, IC50 = 12.10 ± 0.14 and 14.00 ± 2.13), 2-formyl-1,3-dimethoxyantharquinone (7, IC 50 = 13.10 ± 1.02 and 14.80 ± 0.74), 1,3-dimethoxy-2-methylanthraquinone (4, IC50 = 9.40 ± 3.51 and 28.40 ± 2.33), and 1,3-dihydroxy-2-methylanthraquinone (3, IC 50 = 25.60 ± 0.42 and 28.40 ± 0.79) also exhibited moderate cytotoxicity against MCF-7 and K-562 cancer cell lines, respectively. Other structurally related compounds like 1,3-dihydroxyanthraquinone (13a, IC50 = 19.70 ± 0.35 and 14.50 ± 1.28), 1,3-dimethoxyanthraquinone (13b, IC50 = 6.50 ± 0.66 and 5.90 ± 0.95) were also showed good cytotoxicity. The target compound damnacanthal (1) was found to be the most cytotoxic against the MCF-7 and K-562 cancer cell lines, with IC50 values of 3.80 ± 0.57 and 5.50 ± 1.26, respectively. The structures of all compounds were elucidated with the help of detailed spectroscopic techniques.
- Akhtar, Muhammad Nadeem,Zareen, Seema,Yeap, Swee Keong,Ho, Wan Yong,Lo, Kong Mun,Hasan, Aurangzeb,Alitheen, Noorjahan Banu
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p. 10042 - 10055
(2013/09/23)
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- Synthesis and Properties of Anthraquinone-Substituted Porphyrin Compounds
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A synthetic route for the preparation of covalently-linked porphyrin-anthraquinone compounds as models for the phototrap in photosynthesis is described. 5-(2-anthraquinone)-15-(N,N-dimethylaminobenzal)-2,8,12,18-tetraethyl-3,7,13,17-tetramethylporphyrin (DPQ) and its derivatives are synthesized by condensation of 3,3'-diethyl-4,4'-dimethyl-2,2'-dipyrrolylmethane with an appropriate aldehyde in good molecular orientation and higher yield.The structures of new compounds are determined by 1H NMR, UV-visible spectroscopy, FTIR spectroscopy, mass spectrometry and elemental analytical data.Some of the photophysical properties of the compounds are reported with reference to their use as models of the reaction centre in photosynthesis.
- Zhang, Jie,Yang, Guo-Yu,Wen, Ke,Sun, Hao-Ran,Yu, Lian-Xiang,Cao, Xi-Zhang
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p. 613 - 618
(2007/10/03)
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- A MILD METHOD FOR THE CONVERSION OF ACTIVATED ARYL METHYL GROUPS TO CARBOXALDEHYDES VIA THE UNCATALYZED PERIODATE CLEAVAGE OF ANAMINES
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A mild procedure for the oxidative cleavage of aryl enamines to aryl aldehydes by periodate without the need for transition metal catalysis is presented.
- Vetelino, Michael G.,Coe, Jotham W.
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p. 219 - 222
(2007/10/02)
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- S(RN)1 reactions of anthraquinone alkylating agents
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The C-alkylation reaction of three reductive alkylating agents prepared from 2-methylanthraquinone by 2-nitropropane anion is shown to proceed by the S(RN)1 mechanism. The S(RN)1 mechanism is confirmed by the leaving group effect and the inhibitory effect of dioxygen, p-dinitrobenzene, cupric chloride and di-tert-butylnitroxide. This reaction can be extended to 1-methyl-3-nitropyrolidin-2-one anion.
- Crozet,Vanelle,Jentzer,Donini,Maldonado
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p. 11253 - 11262
(2007/10/02)
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- REACTIONS DE SUBSTITUTION SRN1 EN SERIE QUINONIQUE
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Salts derived from 2-nitropropane react with 2-(halomethyl)-9,10-anthracenedione or triethylammonium derivative by a SRN1 mechanism.The operation of this mechanism is confirmed by the leaving group effect and by the inhibitory effect of di-tert-butylnitroxide.A base-promoted nitrous acid elimination gives a 9,10-anthracenedione bearing a trisubstituted ethylenic double bound in the 2 position.
- Crozet, Michel P.,Jentzer, Olivier,Vanelle, Patrice
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p. 5531 - 5534
(2007/10/02)
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