Amphiphilic Carbohydrate-Based Mesogens; I. Mesognic<i>O</i>-<i>n</i>-Alkyl β-D-Mannofuranosides: Synthesis of a Novel Homologous Series of Glycosides

Dahlhoff, W. V.

doi:10.1055/s-1987-27945

Cited by 17 publications

(9 citation statements)

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“…were added to the flask and the reaction was stirred vigorously (800 rpm or higher) at room temperature overnight. Hz, H-6'), 4.19-4.13 (m, 2H, H-6, H-6'), 3.87-3.81 (m, 2H, H-5, H-6), 3.75-3.71 (m, 1H, H-5'), 3.67-3.61 (m, 1H, H-4) 7, 170.8, 170.4, 169.5, 169.4, 165.8, 133.6, 130.0, 129.2, 128.6, 101.3, 97.0, 73.4, 72.8, 72.0, 71.25, 71.23, 70.9, 69.9, 68.7, 68.4, 61.9, 55.4, 39.0, 27.0, 20.8, 20.72, 20.72, 20.70 5, 138.6, 138.5, 138.1, 138.0, 128.6, 128.5, 128.5, 128.5, 128.2, 128.1, 128.0, 127.95, 127.89, 127.85, 127.81, 127.7, 103.9, 97.2, 84.8, 82.1, 77.9, 75.8, 75.1, 74.9, 74.9, 73.6, 73.3, 71.9, 71.7, 70.1, 69.3, 69.0, 55.5, 39.0, 27.2 7,170.3,169.6,169.5,159.6,130.2,129.8,114.1,101.2,98.4,78.8,75.3,73.3,72.9,71.9,71.4,69.9,68.9,68.4,62.5,61.9,55.4,55.3,26.0,20.9,20.8,20.73,20.71,18.4,m/z) 8, 170.4, 170.3, 169.5, 169.3, 159.5, 159.3, 130.7, 130.3, 129.8, 129.7, 113.9, 113.8, 100.8, 99.0, 75.8, 74.9, 73.4, 72.9, 72.1, 71.9, 71.3, 68.8, 68.7, 68.4, 68.2, 61.9, 55.44, 55.39, 55.36, 21.0, 20.8, 20.76, 20.72, 20.70 4,72.8,72.7,72.4,69.6,69.4,69.0,67.5,55.1,18.6. HRMS (ESI,m/z) trimethylsilyl trifluoromethanesulfonate in d...…”

Section: General Procedures D: Sequential Reactions Of Carbohydrate Bomentioning

confidence: 99%

“…5,6 Transient protection via tricoordinate boronic ester formation has been used to accomplish selective acylations, glycosylations, sulfations, alkylations and silylations of carbohydrate derivatives. [7][8][9][10][11][12][13][14][15] polymer-supported boronic acids have also been developed. [16][17][18] A complementary and less widely exploited mode of reactivity for organoboron complexes of sugars is the activation of OH groups by formation of tetracoordinate adducts.…”

Section: Introductionmentioning

confidence: 99%

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Sequential Functionalizations of Carbohydrates Enabled by Boronic Esters as Switchable Protective/Activating Groups

2017

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Processes for site-selective, sequential functionalizations of carbohydrate derivatives are described. In these processes, a tricoordinate boronic ester initially serves as a protective group for a sugar-derived 1,2- or 1,3-diol motif, permitting functionalization of free OH groups. In a second step, addition of a Lewis base generates a tetracoordinate adduct, which serves as an activating group, enabling functionalization of one of the boron-bound oxygen atoms by a second electrophile. By combining an initial acylation, alkylation, or glycosylation step with an amine-mediated glycosylation of the boronic ester, a variety of selectively protected di- and trisaccharide derivatives can be accessed in an operationally simple fashion without purification of intermediates. This Lewis base-triggered switching of behavior from "latent" to "active" nucleophile is a unique feature of boronic esters relative to other protective groups for diol moieties in carbohydrate chemistry.

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Section: General Procedures D: Sequential Reactions Of Carbohydrate Bomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sequential Functionalizations of Carbohydrates Enabled by Boronic Esters as Switchable Protective/Activating Groups

2017

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“…32 shows the structures and transition temperatures of three related mannofuranosides, d, i and j. 48 The results show that when the aliphatic chain is positioned so that it does not sterically interfere with the hydroxyl moieties (a-anomer) then the transition temperatures are higher than when steric hindrance occurs (b-anomers), i.e., the availability of hydroxyl moieties for the purposes of hydrogen bonding with neighbouring molecules markedly affects the stabilities of liquid crystal phases.…”

Section: Furanose Systemsmentioning

confidence: 99%

“…Fig 48. Photomicrograph of the glycolipid-water interface at a temperature of 75 uC with the glycolipid in the liquid state.…”

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confidence: 99%

Thermotropic liquid crystalline glycolipids

et al. 2007

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Are the liquid crystalline properties of the materials of living systems important in biological structures, functions, diseases and treatments? There is a growing consciousness that the observed lyotropic, and often thermotropic liquid crystallinity, of many biological materials that possess key biological functionality might be more than curious coincidence. Rather, as the survival of living systems depends on the flexibility and reformability of structures, it seems more likely that it is the combination of softness and structure of the liquid-crystalline state that determines the functionality of biological materials. The richest sources of liquid crystals derived from living systems are found in cell membranes, of these glycolipids are a particularly important class of components. In this critical review, we will examine the relationship between chemical structure and the self-assembling and self-organising properties of glycolipids that ultimately lead to mesophase formation.

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“…The main product of the reactions in presence of boronic acid was 48 α, which is unusual, since pyranosides are the products of thermodynamic control and predominant in classic Fischer glycosylation. Synthesizing furanosides with Fischer glycosylation is usually not trivial as the level of selectivity depends on the reaction conditions as well as the chosen substrate and catalyst [ 25 ], but there have been previously reported methods that used boronic esters or borate intermediates to prepare furanosides [ 26 , 27 ]. The highest increase in yield (70% of 48 α) was achieved using 2 equiv.…”

Section: Use Of Different Catalysts and Additives For Fischer Glycosy...mentioning

confidence: 99%

Like Visiting an Old Friend: Fischer Glycosylation in the Twenty-First Century: Modern Methods and Techniques

et al. 2022

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Fischer glycosylation is typically the chemical reaction of a monosaccharide and an alcohol in presence of an acidic catalyst to afford glycosides in pyranosidic and furanosidic forms. This reaction is still applied today for the synthesis of specialized glycosides, and optimization and modification of the method have continued since its discovery by Emil Fischer in the 1890s. This review presents advancements in Fischer glycosylation described in literature of the past 15 years and its implementation in modern chemical methods.

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Amphiphilic Carbohydrate-Based Mesogens; I. MesognicO-n-Alkyl β-D-Mannofuranosides: Synthesis of a Novel Homologous Series of Glycosides

Cited by 17 publications

References 0 publications

Sequential Functionalizations of Carbohydrates Enabled by Boronic Esters as Switchable Protective/Activating Groups

Sequential Functionalizations of Carbohydrates Enabled by Boronic Esters as Switchable Protective/Activating Groups

Thermotropic liquid crystalline glycolipids

Like Visiting an Old Friend: Fischer Glycosylation in the Twenty-First Century: Modern Methods and Techniques

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