- Synthesis of per-sulfated flavonoids using 2,2,2-trichloro ethyl protecting group and their factor Xa inhibition potential
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The synthesis of per-sulfated flavonoids, organic compounds with multiple sulfate groups, is challenging. We present here a two-step synthesis of fully sulfated flavonoids in high overall yields using the 2,2,2-trichloroethyl moiety as a protecting group.
- Gunnarsson, Gunnar T.,Riaz, Muhammad,Adams, Joanna,Desai, Umesh R.
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- Iridium-Catalyzed Aryl C-H Sulfonamidation and Amide Formation Using a Bifunctional Nitrogen Source
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A new strategy for the sequential formation of aryl and amidyl C-N bonds is reported. Using trichloroethoxysulfonyl azide as a bifunctional nitrogen source, Ir-catalyzed aryl C-H sulfonamidation and subsequent desulfonative amide formation proceed effectively without any need of oxidants or coupling reagents. This protocol is suitable for readily available benzamides and stable carboxylates including primary, secondary, and tertiary alkyl, alkenyl, and phenyl carboxylates, thereby providing a direct and efficient method for the synthesis of biologically and chemically useful N-arylamides.
- Yu, Meng,Zhang, Tao,Jalani, Hitesh B.,Dong, Xunqing,Lu, Hongjian,Li, Guigen
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supporting information
p. 4828 - 4832
(2018/08/24)
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- Design and synthesis of biphenyl and biphenyl ether inhibitors of sulfatases
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Inhibitors of sulfatase-2 are putative anticancer agents, but the discovery of potent small molecules targeting this enzyme has proved challenging. Based on molecular modelling, two series of sulfatase-2 inhibitors have been developed with biphenyl and biphenyl ether scaffolds judiciously substituted with sulfamate, carboxylate and other polar groups (e.g. amino). Inhibition of aryl sulfatase A and B was also determined. The biphenyl ether derivatives were less selective for sulfatase-2 over aryl sulfatase B than the biphenyl series. All biphenyl ether derivatives inhibited aryl sulfatase A, whereas only amino derivatives inhibited aryl sulfatase B significantly. In the biphenyl series few derivatives exhibited activity against aryl sulfatase B. The trichloroethylsulfamate group was identified as a new pharmacophore enabling potent inhibition of all of the sulfatases studied.
- Reuillon, Tristan,Alhasan, Sari F.,Beale, Gary S.,Bertoli, Annalisa,Brennan, Alfie,Cano, Celine,Reeves, Helen L.,Newell, David R.,Golding, Bernard T.,Miller, Duncan C.,Griffin, Roger J.
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p. 2821 - 2826
(2016/04/06)
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- A concise and scalable strategy for the total synthesis of dictyodendrin B based on sequential C-H functionalization
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A sequential C-H functionalization strategy for the synthesis of the marine alkaloid dictyodendrin B is reported. Our synthesis begins from commercially available 4-bromoindole and involves six direct functionalizations around the heteroarene core as part of a gram-scale strategy towards the natural product.
- Pitts, Andrew K.,O'Hara, Fionn,Snell, Robert H.,Gaunt, Matthew J.
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supporting information
p. 5451 - 5455
(2015/04/27)
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- Sulfation of deoxynivalenol, its acetylated derivatives, and T2-toxin
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The synthesis of several sulfates of trichothecene mycotoxins is presented. Deoxynivalenol (DON) and its acetylated derivatives were synthesized from 3-acetyldeoxynivalenol (3ADON) and used as substrate for sulfation in order to reach a series of five different DON-based sulfates as well as T2-toxin-3-sulfate. These substances are suspected to be formed during phase-II metabolism in plants and humans. The sulfation was performed using a sulfuryl imidazolium salt, which was synthesized prior to use. All protected intermediates and final products were characterized via NMR and will serve as reference materials for further investigations in the fields of toxicology and bioanalytics of mycotoxins.
- Fruhmann, Philipp,Skrinjar, Philipp,Weber, Julia,Mikula, Hannes,Warth, Benedikt,Sulyok, Michael,Krska, Rudolf,Adam, Gerhard,Rosenberg, Erwin,Hametner, Christian,Fr?hlich, Johannes
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p. 5260 - 5266
(2014/07/08)
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- Sulfation of deoxynivalenol, its acetylated derivatives, and T2-toxin
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The synthesis of several sulfates of trichothecene mycotoxins is presented. Deoxynivalenol (DON) and its acetylated derivatives were synthesized from 3-acetyldeoxynivalenol (3ADON) and used as substrate for sulfation in order to reach a series of five different DON-based sulfates as well as T2-toxin-3-sulfate. These substances are suspected to be formed during phase-II metabolism in plants and humans. The sulfation was performed using a sulfuryl imidazolium salt, which was synthesized prior to use. All protected intermediates and final products were characterized via NMR and will serve as reference materials for further investigations in the fields of toxicology and bioanalytics of mycotoxins.
- Fruhmann, Philipp,Skrinjar, Philipp,Weber, Julia,Mikula, Hannes,Warth, Benedikt,Sulyok, Michael,Krska, Rudolf,Adam, Gerhard,Rosenberg, Erwin,Hametner, Christian,Fr?hlich, Johannes
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p. 5260 - 5266
(2014/12/10)
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- Sulfation of β-resorcylic acid esters - First synthesis of zearalenone-14-sulfate
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The chemical sulfation of β-resorcylic acid esters was investigated by applying state of the art procedures for the synthesis and deprotection of 2,2,2-trichloroethyl protected sulfates as appropriate intermediates. The selectivity of monosulfation was st
- Mikula, Hannes,Sohr, Barbara,Skrinjar, Philipp,Weber, Julia,Hametner, Christian,Berthiller, Franz,Krska, Rudolf,Adam, Gerhard,Fr?hlich, Johannes
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supporting information
p. 3290 - 3293
(2013/06/27)
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- From homogeneous to heterogeneous catalysis of the three-component coupling of oxysulfonyl azides, alkynes, and amines
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A reliable procedure for the synthesis of oxysulfonyl azides has been developed and applied to the three-component coupling reactions of azides, alkynes, and amines catalyzed homogeneously by CuI, which led to the formation of N-oxysulfonyl amidines with
- Yang, Tao,Cui, Hao,Zhang, Changhe,Zhang, Li,Su, Cheng-Yong
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p. 3131 - 3138
(2013/10/21)
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- ALKENE AZIRIDINATION
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A process for the asymmetric aziridination of an alkene comprising treating the alkene with a sulfonyl azide, preferably trichloroethoxysulfonyl azide, in the presence of a cobalt(II) porphyrin.
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Page/Page column 27
(2010/09/17)
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- O- and N-sulfations of carbohydrates using sulfuryl imidazolium salts
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(Chemical Equation Presented) A series of sulfuryl imidazolium salts (SISs) were prepared and examined as reagents for incorporating trichloroethyl- protected sulfate esters into carbohydrates. The SIS that contained a 1,2-dimethylimidazolium moiety (SIS
- Ingram, Laura J.,Desoky, Ahmed,Ali, Ahmed M.,Taylor, Scott D.
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supporting information; experimental part
p. 6479 - 6485
(2010/01/16)
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- A general sequence independent solid phase method for the site specific synthesis of multiple sulfated-tyrosine containing peptides
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In this communication, a new site specific synthesis of highly functionalized and multiple sulfated peptides using convential Fmoc-tBu solid phase peptide synthesis is described. The Royal Society of Chemistry 2009.
- Bunschoten, Anton,Kruijtzer, John A. W.,Ippel, Johannes H.,De Haas, Carla J. C.,Van Strijp, Jos A. G.,Kemmink, Johan,Liskamp, Rob M. J.
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supporting information; experimental part
p. 2999 - 3001
(2009/12/01)
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- Highly asymmetric cobalt-catalyzed aziridination of alkenes with trichloroethoxysulfonyl azide (TcesN3)
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A Co(ii)-based catalytic system has been developed for asymmetric aziridination of alkenes with trichloroethoxysulfonyl azide (TcesN3) under mild conditions, forming the corresponding N-Tces-aziridines in high yields and excellent enantioselect
- Subbarayan, Velusamy,Ruppel, Joshua V.,Zhu, Shifa,Perman, Jason A.,Zhang, X. Peter
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supporting information; experimental part
p. 4266 - 4268
(2011/03/19)
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- Catalytic intermolecular amination of C-H bonds: Method development and mechanistic insights
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Reaction methodology for intermolecular C-H amination of benzylic and 3° C-H bonds is described. This process uses the starting alkane as the limiting reagent, gives optically pure tetrasubstituted amines through stereospecific insertion into enantiomeric 3° centers, displays high chemoselectivity for benzylic oxidation, and enables the facile preparation of isotopically enriched 15N-labeled compounds. Access to substituted amines, amino alcohols, and diamines is thereby made possible in a single transformation. Important information relevant to understanding the initial steps in the catalytic cycle, reaction chemoselectivity, the nature of the active oxidant, and pathways for catalyst inactivation has been gained through mechanistic analysis; these studies are also presented.
- Fiori, Kristin Williams,Du Bois
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p. 562 - 568
(2007/10/03)
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- Total syntheses of the telomerase inhibitors dictyodendrin B, C, and E
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Concise and flexible total syntheses of the pyrrolo[2,3-c]carbazole alkaloids dictyodendrin B (2), C (3), and E (5) are described. These polycyclic telomerase inhibitors of marine origin derive from the common intermediate 18 which was prepared on a multigram scale by a sequence comprising a TosMIC cycloaddition with formation of the pyrrole A-ring, a titanium-induced reductive oxoamide coupling reaction to generate an adjacent indole nucleus, and a photochemical 6π-electrocyclization/aromatization tandem to forge the pyrrolocarbazole core. Conversion of 18 into dictyodendrin C required selective manipulations of the lateral protecting groups and oxidation with peroxoimidic acid to form the vinylogous benzoquinone core of the target. Zinc-induced reductive cleavage of the trichloroethyl sulfate ester then completed the first total synthesis of 3. Its relatives 2 and 5 also originate from compound 18 by a selective bromination of the pyrrole entity followed by elaboration of the resulting bromide 27 via metal-halogen exchange or cross-coupling chemistry, respectively. Particularly noteworthy in this context is the generation of the very labile p-quinomethide motif of dictyodendrin E by a palladium-catalyzed benzyl cross-coupling reaction followed by vinylogous oxidation of the resulting product 41 with DDQ. The Suzuki step could only be achieved with the aid of the borate complex 40 formed in situ from p-methoxybenzylmagnesium chloride and 9-MeO-9-BBN, whereas alternative methods employing benzylic boronates, -trifluoroborates, or -stannanes met with failure.
- Fuerstner, Alois,Domostoj, Mathias M.,Scheiper, Bodo
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p. 8087 - 8094
(2007/10/03)
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- Total synthesis of dictyodendrin B
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A concise total synthesis of dictyodendrin B (1) is reported, a scarce marine alkaloid endowed with promising telomerase inhibitory activity. Key steps of the chosen route are a reductive cyclization of ketoamide 11 to indole 12 mediated by low-valent titanium (from TiCl3 and KC8) followed by a photochemical 6π-electrocyclization, which was performed in the presence of Pd/C and nitrobenzene to effect concomitant dehydrogenation/aromatization of the product initially formed. Regioselective bromination of the resulting pyrrolocarbazole 13 followed by lithium/bromine exchange and quenching of the resulting organolithium species with p-methoxybenzaldehyde installed the side chain at C2. Oxidation of the benzylic alcohol 15 thus obtained to ketone 17 was best achieved with catalytic amounts of tetra-n-propylammonium perruthenate (TPAP) and N-methylmorpholine-N-oxide (NMO) in dilute CH2Cl2 solution to avoid the formation of undue amounts of the unsymmetrical dimer 16. Ketone 17 was elaborated into the natural product by selective cleavage of the isopropyl ether with BCl3, introduction of the sulfate moiety with the aid of trichloroethyl chlorosulfuric acid ester, deprotection of all lateral methyl ether groups, and final reductive cleavage of the trichloroethyl ester moiety. The spectroscopic data of synthetic dictyodendrin B thus formed matched those of an authentic sample in all regards. Moreover, it was shown that global deprotection of the peripheral -OH groups in pyrrolo[2,3-c]carbazole 13 is accompanied by spontaneous air-oxidation to form the quinone core of dictyodendrin C. Copyright
- Fuerstner, Alois,Domostoj, Mathias M.,Scheiper, Bodo
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p. 11620 - 11621
(2007/10/03)
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