Ultraschallforcierte Reaktionen; Synthese und Charakterisierung amphiphiler 4, 6‐O (n‐Alkyliden)‐D‐glucopyranosen

Miethchen, Ralf; Peters, D.

doi:10.1002/zfch.19880280819

Cited by 11 publications

References 8 publications

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Amphiphilic carbohydrate‐based mesogens, VII. Synthesis of mesogenic 4‐ and 6‐O‐alkyl‐D‐glucitols

Dahlhoff

1991

Liebigs Ann. Chem.

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Both the hemiacetal and acetal groups of 4,6-O-alkylidene-2a -e. Subsequent deboronations give ca. 1 : 1 mixtures of a/P-D-glucopyranoses (hexylidenedecylidene, 1 ae) are 4-O-alkyl-~-glucitols 3 ae and 6-O-alkyl-~-glucitols 4ae, quantitatively reduced by ethyldiboranes(6) in the presence of which are separated to give mesogenic 3 and 4. Both 3 and 4 9-methylsulfonyloxy-9-borabicyclo[3.3.l]nonane (MSBBN) afexhibit smectic A liquid crystalline phases. ter conversion to their 1,2,3-tri-O-diethylboryl derivatives

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Amphiphilic carbohydrate‐based mesogens, VII. Synthesis of mesogenic 4‐ and 6‐O‐alkyl‐D‐glucitols

Dahlhoff

1991

Liebigs Ann. Chem.

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Flüssigkristalline 4,6‐O‐(n‐Alkyliden)‐D‐glucopyranosen

et al. 1991

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Organofluorine compounds and fluorinating agents. 14. Thermotropic Liquid-Crystalline Glycosyl Fluorides

Miethchen

Zur

1995

J. Prakt. Chem.

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The liquid crystalline 6‐O‐alkyl‐α‐D‐galactopyranosyl fluorides (3a–f) and the mesogenic 6‐O‐dodecyl‐α‐D‐glucopyranosyl fluoride (7) were prepared from the homologous 6‐O‐alkyl‐1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranosides (1a–f) and from the methyl 2,3,4‐tri‐O‐benzyl‐glucopyranoside (4), respectively, in two and three steps. The fluorinations of 1a–f to the α‐fluorides 2a–f and of 5 to the α‐fluoride 6 were carried out with the reagent system HF/nitromethane/acetic anhydride, which simultaneously effects the complete exchange of the isopropylidene groups (1a‐f) and of the benzyl groups (5) for acetyl functions in the non‐glycosidic positions. Moreover, the 6‐O‐dodecyl‐2,3,4‐tri‐O‐acetyl‐α‐D‐galactopyranosyl fluoride (11) was prepared in three steps from the 6‐O‐dodecylgalactopyranose (8). The stereoselective introduction of the fluoride into the β‐anomeric position (10 → 11) was achieved by bromide‐fluoride exchange with the two‐phase system triethylamine‐trishydrofluoride/petroleum ether. Dodecyl 6‐deoxy‐6‐fluoro‐α‐D‐glucopyranoside (13), prepared from the glucoside 12 with the fluorinating agent DAST, shows a narrow monotropic SA‐phase and lyotropic liquid crystalline behaviour in contact with water. Dodecyl 6‐deoxy‐6‐fluoro‐β‐D‐galactopyranoside (17), prepared in three steps from the acetal 14, does not form mesophases. The liquid crystalline behaviour of the amphiphilic glycosyl fluorides 3a–f, 7, and of the 6‐deoxy‐6‐fluoro derivative 13 is described.

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Ultraschallforcierte Reaktionen; Synthese und Charakterisierung amphiphiler 4, 6‐O (n‐Alkyliden)‐D‐glucopyranosen

Cited by 11 publications

References 8 publications

Amphiphilic carbohydrate‐based mesogens, VII. Synthesis of mesogenic 4‐ and 6‐O‐alkyl‐D‐glucitols

Amphiphilic carbohydrate‐based mesogens, VII. Synthesis of mesogenic 4‐ and 6‐O‐alkyl‐D‐glucitols

Flüssigkristalline 4,6‐O‐(n‐Alkyliden)‐D‐glucopyranosen

Organofluorine compounds and fluorinating agents. 14. Thermotropic Liquid-Crystalline Glycosyl Fluorides

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