Synthesis, crystalline structure, conformational analysis, and azidolysis of methyl 2,3-anhydro-α-d-manno- and -allo-pyranoside p-bromobenzyl

Wu, Xiaochun; Kong, Fanzuo; Lu, Depei; Li, Genpei

doi:10.1016/0008-6215(92)80086-g

Cited by 15 publications

(14 citation statements)

References 21 publications

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“…The "straitjacket" effect of the 2,3-epithio rings enforces mean values of about 0.28 for the torsion angle about C1-C2-C3-C4 by forcing the pyranoside rings into this rigid conformation. Almost identical pyranoside geometries were also found in the solid-state structures of methyl 2,3-anhydro-4,6-bis(O-p-bromobenzyl)-a-d-mannopyranoside and its allo isomer [11] as well as per-2,3-anhydro-a-cyclomannin. [12] Corey-Pauling-Koltun (CPK) models and contact surface [13] representations reveal that the epithioalloside units of 2 are arranged to form a cavity whose shape is reversed from that of cyclodextrins; that is, the side on which the primary 6-OH groups reside is much wider than the other side (top side).…”

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confidence: 67%

Synthesis of a Cycloallin Derivative from β‐Cyclodextrin: Heptakis(2,3‐dideoxy‐2,3‐epithio)‐β‐cycloallin

et al. 2005

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Macrocyclic molecules that comprise several subunits in a circular array exhibit novel functions that are otherwise not observed in the individual units. Many host molecules that consist of several identical functional subunits, such as cyclodextrins, cyclophanes, and their related natural and artificial macrocycles, have been prepared by enzymatic or synthetic methods and have developed the concept of artificial molecular recognition and catalysis.[1] Cyclodextrins, in particular, have been the leading compounds from the initial stage of this research. Despite extensive studies on the functionalization of cyclodextrins for diverse purposes such as the development of artificial receptors and enzymes, their modification has been limited mostly to their primary hydroxy groups while secondary sites have received much less attention.[2] Moreover, successful studies on complete modifications at the secondary sites are rare as the modifications on 2-OH or 3-OH do not proceed selectively and are accompanied inevitably by products of either over-or undermodification. Only per(3,6-anhydro)- [3] and per(2-O-tosyl)-cyclodextrins, [4] per(2,3-anhydro)-cyclomannins 1 (see Scheme 1), [4,5] cycloaltrins, [6] per(3-amino-3-deoxy)-b-cycloaltrin, [7] and per(3-deoxy)-cyclomannins [8] are available by the selective modifications of cyclodextrins at the present time. However, to the best of our knowledge, the preparation of a cycloallin family has not been studied as yet.Here, we report the first successful one-pot preparation of a novel type of cycloallin derivative, 2, from cyclomannin derivative 1, which itself is obtained in three steps from bcyclodextrin (Scheme 1). The synthesis is as simple as heating an aqueous acidic solution of 1 at 90 8C for 30 min followed by stirring at room temperature under alkaline conditions. It is quite astonishing that these simple reaction conditions not only ensure a complete conversion of the seven epoxide

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confidence: 67%

Synthesis of a Cycloallin Derivative from β‐Cyclodextrin: Heptakis(2,3‐dideoxy‐2,3‐epithio)‐β‐cycloallin

et al. 2005

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“…This implies an essentially planar arrangement of C-1 to C-4, as expressed in the very small value (0.5 AE 3.48) for the C1-C2-C3-C4 torsion angle. In Table 1, these geometry descriptors are compared with those found in the solid-state structure of methyl 2,3-anhydro-4,6-di-O-(p-bromobenzyl)-a-d-mannopyranoside (5), [13] whose O H 5 pyranoid ring conformation closely resembles that found in 4. The primary 6-OH groups adopt gauche ± trans (gt, w % 608) and gauche ± gauche arrangements (gg, w %À 608) relative to the pyranoid ring, that is either point towards the center of the cavity (gt) or away from it (gg).…”

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confidence: 99%

Structure and Lipophilicity Profile of 2,3-Anhydro-α-cyclomannin and Its Ethanol Inclusion Complex

et al. 2000

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Readily available from alpha-cyclodextrin in three steps, 2,3-anhydro-alpha-cyclomannin composed of six alpha-(1-->4)-linked 2,3-anhydro-D-mannopyranose residues, crystallizes well when precipitated from aqueous ethanol. An X-ray structure reveals the macrocycle to contain ethanol in its cavity, thus representing the first inclusion complex of a non-glucose cyclooligosaccharide. The wider rim of the torus-shaped macrocycle holds the six epoxide rings whose oxygens point away from the cavity, thereby sculpturing the unique over-all shape of a six-pointed star.

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“…É interessante observar que um método alternativo foi descrito por Wu e colaboradores 14 , que afirmam obter apenas o produto desejado, quando utilizam grupos protetores adequados e condições de reação especiais. Experimentamos esse método e, ao contrário do afirmado pelos autores, obtivemos misturas de isômeros absolutamente semelhantes às obtidas na síntese acima descrita.…”

Section: Resultsunclassified

Síntese de aminoglicosídeos, precursores de pseudo-dissacarídeos potencialmente ativos

Carvalho¹,

Haines²

2000

Quím. Nova

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Recebido em 16/11/98; aceito em 27/7/99 SYNTHESIS OF AMINOGLYCOSIDES AS PRECURSORS OF POTENTIALLY ACTIVES PSEUDODISACCHARIDES. This work describes the syntheses of O-protected aminoglycosides as an important block building for the preparation of potential bioactive pseudodisaccharide. The new O-protected methyl 3-amino-3-deoxy-α α α α α-D-glycopyranoside 4 and methyl 2-amino-2-deoxy-α α α α α-D-glycopyranoside 5 were prepared, respectively, in five and four steps. All compounds were obtained in good yield and characterized by spectral data ( 1 H and 13 C NMR, MS, IR) and elemental analysis.

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Synthesis, crystalline structure, conformational analysis, and azidolysis of methyl 2,3-anhydro-α-d-manno- and -allo-pyranoside p-bromobenzyl

Cited by 15 publications

References 21 publications

Synthesis of a Cycloallin Derivative from β‐Cyclodextrin: Heptakis(2,3‐dideoxy‐2,3‐epithio)‐β‐cycloallin

Synthesis of a Cycloallin Derivative from β‐Cyclodextrin: Heptakis(2,3‐dideoxy‐2,3‐epithio)‐β‐cycloallin

Structure and Lipophilicity Profile of 2,3-Anhydro-α-cyclomannin and Its Ethanol Inclusion Complex

Síntese de aminoglicosídeos, precursores de pseudo-dissacarídeos potencialmente ativos

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