101
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Patalag LJ, Sibold J, Schütte OM, Steinem C, Werz DB. Gb 3 Glycosphingolipids with Fluorescent Oligoene Fatty Acids: Synthesis and Phase Behavior in Model Membranes. Chembiochem 2017; 18:2171-2178. [PMID: 28941080 DOI: 10.1002/cbic.201700414] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Indexed: 12/11/2022]
Abstract
Glycosphingolipids are involved in a number of physiological and pathophysiological processes, and they serve as receptors for a variety of bacterial toxins and viruses. To investigate their function in lipid membranes, fluorescently labeled glycosphingolipids are highly desirable. Herein, a synthetic route to access Gb3 glycosphingolipids with fluorescently labeled fatty acids, consisting of pentaene and hexaene moieties either at the terminus or in the middle of the acyl chain, has been developed. The fluorescent properties of the Gb3 derivatives were investigated in small unilamellar vesicles composed of a raft-like mixture. Phase-separated giant unilamellar vesicles (GUVs) allowed the quantification of the apparent partitioning coefficients of the Gb3 compounds by means of confocal fluorescence laser scanning microscopy. The determined partition coefficients demonstrate that the Gb3 derivatives are preferentially localized in the liquid-disordered (ld ) phase. To analyze whether the compounds behave like their physiological counterparts, Cy3-labeled (Cy: cyanine) Shiga toxin B subunits (STxB) were specifically bound to Gb3 -doped GUVs. However, the protein was favorably localized in the ld phase, in contrast to results reported for STxB bound to naturally occurring Gb3 , which is discussed in terms of the packing density of the lipids in the liquid-ordered (lo ) phase.
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102
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Wonner P, Vogel L, Düser M, Gomes L, Kniep F, Mallick B, Werz DB, Huber SM. Innenrücktitelbild: Aktivierung einer Kohlenstoff-Halogen-Bindung durch selenbasierte Chalkogenbrücken (Angew. Chem. 39/2017). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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103
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Garve LKB, Kreft A, Jones PG, Werz DB. Synthesis of 2-Unsubstituted Pyrrolidines and Piperidines from Donor–Acceptor Cyclopropanes and Cyclobutanes: 1,3,5-Triazinanes as Surrogates for Formylimines. J Org Chem 2017; 82:9235-9242. [DOI: 10.1021/acs.joc.7b01631] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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104
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Wonner P, Vogel L, Düser M, Gomes L, Kniep F, Mallick B, Werz DB, Huber SM. Inside Back Cover: Carbon-Halogen Bond Activation by Selenium-Based Chalcogen Bonding (Angew. Chem. Int. Ed. 39/2017). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/anie.201707295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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105
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Lücht A, Patalag LJ, Augustin AU, Jones PG, Werz DB. Reactions of Donor-Acceptor Cyclopropanes with Naphthoquinones: Redox and Lewis Acid Catalysis Working in Concert. Angew Chem Int Ed Engl 2017; 56:10587-10591. [DOI: 10.1002/anie.201703732] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Indexed: 01/12/2023]
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106
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Lücht A, Patalag LJ, Augustin AU, Jones PG, Werz DB. Reaktionen von Donor-Akzeptor-Cyclopropanen mit Naphthochinonen: eine Kombination aus Redox- und Lewis-Säure-Katalyse. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703732] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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107
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Wonner P, Vogel L, Düser M, Gomes L, Kniep F, Mallick B, Werz DB, Huber SM. Carbon-Halogen Bond Activation by Selenium-Based Chalcogen Bonding. Angew Chem Int Ed Engl 2017; 56:12009-12012. [PMID: 28605080 PMCID: PMC5638094 DOI: 10.1002/anie.201704816] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Indexed: 12/19/2022]
Abstract
Chalcogen bonding is a little explored noncovalent interaction similar to halogen bonding. This manuscript describes the first application of selenium‐based chalcogen bond donors as Lewis acids in organic synthesis. To this end, the solvolysis of benzhydryl bromide served as a halide abstraction benchmark reaction. Chalcogen bond donors based on a bis(benzimidazolium) core provided rate accelerations relative to the background reactivity by a factor of 20–30. Several comparative experiments provide clear indications that the observed activation is due to chalcogen bonding. The performance of the chalcogen bond donors is superior to that of a related brominated halogen bond donor.
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108
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Wonner P, Vogel L, Düser M, Gomes L, Kniep F, Mallick B, Werz DB, Huber SM. Aktivierung einer Kohlenstoff-Halogen-Bindung durch selenbasierte Chalkogenbrücken. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704816] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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109
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Garve LKB, Jones PG, Werz DB. Ring-Opening 1-Amino-3-aminomethylation of Donor-Acceptor Cyclopropanes via 1,3-Diazepanes. Angew Chem Int Ed Engl 2017; 56:9226-9230. [DOI: 10.1002/anie.201704619] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Indexed: 11/07/2022]
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110
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Garve LKB, Jones PG, Werz DB. Ringöffnende 1-Amino-3-aminomethylierung von Donor-Akzeptor-substituierten Cyclopropanen über 1,3-Diazepane. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704619] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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111
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Patalag LJ, Ulrichs JA, Jones PG, Werz DB. Decorated BODIPY Fluorophores and Thiol-Reactive Fluorescence Probes by an Aldol Addition. Org Lett 2017; 19:2090-2093. [PMID: 28388060 DOI: 10.1021/acs.orglett.7b00693] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A novel entry to meso-decorated BODIPY motifs on the basis of an unusual aldol-type addition with diethyl ketomalonate is reported. The evolving β-hydroxyl group can be optionally eliminated, which suppresses the fluorescence of the BODIPY core by attachment of a π-electronically coupled methylidene malonate unit. This unit serves as a versatile, highly electrophilic acceptor platform for various nucleophilic additions. Corresponding products benefit from a fully restored fluorescence.
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112
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Milde B, Pawliczek M, Jones PG, Werz DB. Enantioselective Total Synthesis of (+)-Lysergol: A Formal anti-Carbopalladation/Heck Cascade as the Key Step. Org Lett 2017; 19:1914-1917. [PMID: 28357872 DOI: 10.1021/acs.orglett.7b00675] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The enantioselective synthesis of (+)-lysergol was completed in 12 steps and an overall yield of 13% starting from a known literature precursor. The key step relies on a domino reaction containing a formal anti-carbopalladation, which is terminated by a β-silyl-directed Heck reaction. During this transformation, the two six-membered rings of the ergot scaffold are formed in a completely stereospecific manner.
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113
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Witt H, Savić F, Oelkers M, Awan SI, Werz DB, Geil B, Janshoff A. Size, Kinetics, and Free Energy of Clusters Formed by Ultraweak Carbohydrate-Carbohydrate Bonds. Biophys J 2016; 110:1582-1592. [PMID: 27074683 DOI: 10.1016/j.bpj.2016.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/15/2016] [Accepted: 03/08/2016] [Indexed: 10/21/2022] Open
Abstract
Weak noncovalent intermolecular interactions play a pivotal role in many biological processes such as cell adhesion or immunology, where the overall binding strength is controlled through bond association and dissociation dynamics as well as the cooperative action of many parallel bonds. Among the various molecules participating in weak bonds, carbohydrate-carbohydrate interactions are probably the most ancient ones allowing individual cells to reversibly enter the multicellular state and to tell apart self and nonself cells. Here, we scrutinized the kinetics and thermodynamics of small homomeric Lewis X-Lewis X ensembles formed in the contact zone of a membrane-coated colloidal probe and a solid supported membrane ensuring minimal nonspecific background interactions. We used an atomic force microscope to measure force distance curves at Piconewton resolution, which allowed us to measure the force due to unbinding of the colloidal probe and the planar membrane as a function of contact time. Applying a contact model, we could estimate the free binding energy of the formed adhesion cluster as a function of dwell time and thereby determine the precise size of the contact zone, the number of participating bonds, and the intrinsic rates of association and dissociation in the presence of calcium ions. The unbinding energy per bond was found to be on the order of 1 kBT. Approximately 30 bonds were opened simultaneously at an off-rate of koff = 7 ± 0.2 s(-1).
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114
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Patalag LJ, Werz DB. Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts. Beilstein J Org Chem 2016; 12:2739-2747. [PMID: 28144344 PMCID: PMC5238556 DOI: 10.3762/bjoc.12.270] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/01/2016] [Indexed: 11/23/2022] Open
Abstract
Herein, we report on the synthesis and characterization of novel fluorescent fatty acids with large Stokes shifts. Three examples consisting of the same number of carbon atoms and thus of similar chain length are presented differing in their degree of unsaturation. As major fluorogenic contributor at the terminus benzo[c][1,2,5]thiadiazole was used. Respective syntheses based on Wittig reactions followed by iodine-mediated isomerization are presented. The absorption properties are modulated by the number of conjugated C=C double bonds of the oligoene chain ranging from one to three. Large Stokes shifts of about 4900-5700 cm-1 and fluorescence quantum yields of up to 0.44 were observed.
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115
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Abstract
![]()
Donor–acceptor
cyclopropanes with two geminal carboxylic
esters are reacted with chalcogenyl chlorides and bromides to afford
ring-opened products bearing the halogen atoms in the 1-position,
adjacent to the donor, and the chalcogenyl residue in the 3-position
next to the two acceptor groups. A variety of different donors (e.g.,
aryl, N, and O) are used. The stereospecificity of the reaction is
demonstrated by using a chiral starting material.
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116
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Wallbaum J, Garve LKB, Jones PG, Werz DB. Ring-Opening Regio-, Diastereo-, and Enantioselective 1,3-Chlorochalcogenation of Cyclopropyl Carbaldehydes. Chemistry 2016; 22:18756-18759. [PMID: 27868248 PMCID: PMC6680189 DOI: 10.1002/chem.201605265] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Indexed: 12/16/2022]
Abstract
meso‐Cyclopropyl carbaldehydes are treated in the presence of an organocatalyst with sulfenyl and selenyl chlorides to afford 1,3‐chlorochalcogenated products. The transformation is achieved by a merged iminium–enamine activation. The enantioselective desymmetrization reaction, leading to three adjacent stereocenters, furnished the target products in complete regioselectivity and moderate to high diastereo‐ and enantioselectivities (d.r. up to 15:1 and e.r. up to 93:7).
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117
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Patalag LJ, Jones PG, Werz DB. BOIMPYs - ein schneller Zugang zu einer Familie rot emittierender Fluorophore und NIR-Farbstoffe. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201606883] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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118
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Patalag LJ, Jones PG, Werz DB. BOIMPYs: Rapid Access to a Family of Red-Emissive Fluorophores and NIR Dyes. Angew Chem Int Ed Engl 2016; 55:13340-13344. [DOI: 10.1002/anie.201606883] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 01/10/2023]
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119
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Düfert A, Werz DB. Carbopalladation Cascades Using Carbon-Carbon Triple Bonds: Recent Advances to Access Complex Scaffolds. Chemistry 2016; 22:16718-16732. [PMID: 27667738 DOI: 10.1002/chem.201603044] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Indexed: 12/13/2022]
Abstract
Alkynes are one of the most versatile functional groups as synthetic handles. They allow for a direct access to partially or fully substituted alkenes through difunctionalization reactions. A prominently utilized transformation for these sequences is the carbopalladation of alkynes, which can be followed by various termination steps such as aromatizations, dearomatizations, cross-coupling reactions, or pericyclic processes, amongst others. This Minireview provides an overview of the recent literature published in the field of carbopalladation chemistry, both with a focus on methodology as well as its application in the syntheses of complex molecular scaffolds, natural products, and functional molecules.
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120
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Milde B, Reding A, Geffers FJ, Jones PG, Werz DB. Intramoleculartrans-Dicarbofunctionalization of Alkynes by a Formalanti-Carbopalladation/Stille Cascade. Chemistry 2016; 22:14544-7. [DOI: 10.1002/chem.201603784] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Indexed: 01/29/2023]
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121
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Werz DB. Cyclopropanes in Organic Synthesis. By Oleg G. Kulinkovich. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/anie.201603984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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122
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Schütte OM, Patalag LJ, Weber LMC, Ries A, Römer W, Werz DB, Steinem C. 2-Hydroxy Fatty Acid Enantiomers of Gb3 Impact Shiga Toxin Binding and Membrane Organization. Biophys J 2016; 108:2775-8. [PMID: 26083916 DOI: 10.1016/j.bpj.2015.05.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/04/2015] [Accepted: 05/12/2015] [Indexed: 11/29/2022] Open
Abstract
Shiga toxin subunit B (STxB) binding to its cellular receptor Gb3 leads to the formation of protein-lipid clusters and bending of the membrane. A newly developed synthetic route allowed synthesizing the biologically most relevant Gb3-C24:1 2OH species with both, the natural (Gb3-R) as well as the unnatural (Gb3-S) configuration of the 2OH group. The derivatives bind STxB with identical nanomolar affinity, while the propensity to induce membrane tubules in giant unilamellar vesicles is more pronounced for Gb3-S. Fluorescence and atomic force microscopy images of phase-separated supported membranes revealed differences in the lateral organization of the protein on the membrane. Gb3-R favorably induces large and tightly packed protein clusters, while a lower protein density is found on Gb3-S doped membranes.
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123
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Kettelhoit K, Werz DB. Synthesis of stigmasteryl (β1→4)-oligoglucosides. J Carbohydr Chem 2016. [DOI: 10.1080/07328303.2015.1136321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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124
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Stefaniu C, Ries A, Gutowski O, Ruett U, Seeberger PH, Werz DB, Brezesinski G. Impact of Structural Differences in Galactocerebrosides on the Behavior of 2D Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2436-2444. [PMID: 26907993 DOI: 10.1021/acs.langmuir.5b03830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The molecular interactions of three biologically important galactocerebrosides have been studied in monolayers formed at the soft air/water interface as 2D model membranes. Highly surface-sensitive techniques as GIXD (grazing incidence X-ray diffraction), IRRAS (infrared reflection-absorption spectroscopy), and BAM (Brewster angle microscopy) have been used. The study reveals that small differences in the chemical structure have a relevant impact on the physical-chemical properties and intermolecular interactions. The presence of a 2-d-hydroxyl group in the fatty acid favored for GalCer C24:0 (2-OH) monolayers a higher hydration state of the headgroup at low lateral pressures (<25 mN/m) and a higher condensation effect above 30 mN/m. An opposite behavior was recorded for GalCer C24:0 and GalCer C24:1, for which the intermolecular interactions are defined by the weakly hydrated but strong H-bonded interconnected head groups. Additionally, the 15-cis-double bond in the fatty acid chain (nervonic acid) of GalCer C24:1 stabilized the LE phase but did not disturb the packing parameters of the LC phase as compared with the saturated compound GalCer C24:0.
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125
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Pawliczek M, Garve LKB, Werz DB. Exploiting amphiphilicity: facile metal free access to thianthrenes and related sulphur heterocycles. Chem Commun (Camb) 2016; 51:9165-8. [PMID: 25948531 DOI: 10.1039/c5cc01757b] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Benzodithioloimines are reacted with arynes or alkynes substituted with electron-withdrawing groups to afford the corresponding thianthrene or benzo[b][1,4]dithiine derivatives. The transformation takes place under mild reaction conditions without any transition metal. Furthermore, the reaction mode could be expanded to 2-thiocyanatopyrroles yielding pyrrolothiazoles.
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