Glucopyranose

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Fanzuo Kong - One of the best experts on this subject based on the ideXlab platform.

  • syntheses and reactions of 5 o acetyl 1 2 anhydro 3 o benzyl α d ribofuranose and β d lyxofuranose 5 o acetyl 1 2 anhydro 3 6 di o benzyl and 1 2 anhydro 5 6 di o benzoyl 3 o benzyl β d mannofuranose and 6 o acetyl 1 2 anhydro 3 4 di o benzyl α d Glucopyranose and β d talopyranose
    2001
    Co-Authors: Jun Ning, Fanzuo Kong
    Abstract:

    The title compounds 5-O-acetyl-1,2-anhydro-3-O-benzyl-alpha-D-ribofuranose and 5-O-acetyl-1,2-anhydro-3-O-benzyl-beta-D-lyxofuranose, and 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-alpha-D-Glucopyranose and 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-beta-D-talopyranose, and 5-O-acetyl-1,2-anhydro-3,6-di-O-benzyl-beta-D-mannofuranose and 1,2-anhydro-5,6-di-O-benzoyl-3-O-benzyl-beta-D-mannofuranose have each been synthesized from the corresponding 2-O-tosylate and 1-free hydroxyl intermediates by base-initiated intramolecular S(N)2 ring closure in almost quantitative yields. Acetyl and benzoyl groups were not affected in the ring closure reactions. Condensation of 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-alpha-D-Glucopyranose and 5-O-acetyl-1,2-anhydro-3,6-di-O-benzyl-beta-D-mannofuranose with 1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose in the presence of ZnCl2 as the catalyst afforded the 1,2-trans-linked 6-O-acetyl-3,4-di-O-benzyl-beta-D-glucopyranosyl-(1-->6)-1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose and 5-O-acetyl-3,6-di-O-benzyl-alpha-D-mannofuranosyl-(1-->6)-1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose as the sole products in satisfactory yields, while condensation of 5-O-acetyl-1,2-anhydro-3-O-benzyl-beta-D-lyxofuranose with 3-O-benzyl-1,2-O-isopropylidene-alpha-D-xylofuranose yielded the 1,2-trans-linked 5-O-acetyl-3-O-benzyl-alpha-D-lyxofuranosyl-(1-->5)-3-O-benzyl-1,2-O-isopropylidene-alpha-D-xylofuranose as the sole product in a good yield. The 6-O-acetyl group in the glycosyl donor, 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-alpha-D-Glucopyranose, did not influence the stereoselectivity of the ring-opening-coupling reaction.

  • a highly convergent and effective synthesis of the phytoalexin elicitor hexasaccharide
    1999
    Co-Authors: Wei Wang, Fanzuo Kong
    Abstract:

    Abstract The peracetylated hexasaccharide 1,2,4-tri-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-6-O-(2,3,4-tri-O-acetyl-6-O-(2,4-di-O-acetyl-3,6-di-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-β- d -glucopyranosyl)-β- d -glucopyranosyl)-α,β- d -Glucopyranose 21 was synthesized in a blockwise manner, employing trisaccharide trichloroacetimidate 2,4-di-O-acetyl-3,6-di-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-α- d -glucopyranosyl trichloroacetimidate 17 as the glycosyl donor, and trisaccharide 4-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-6-O-(2,3,4-tri-O-acetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -Glucopyranose 18 as the acceptor. The donor 17 and acceptor 18 were readily prepared from trisaccharides 3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-6-O-(2,3,4-tri-O-acetyl-6-O-chloroacetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -Glucopyranose 10 and 3,6-di-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -Glucopyranose 11, respectively, which were obtained from rearrangement of orthoesters 3,4-di-O-acetyl-6-O-chloroacetyl-α- d -Glucopyranose 1,2-(3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -glucopyranosid-6-yl orthoacetate) 8 and 3,4,6-tri-O-acetyl-α- d -Glucopyranose 1,2-(3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -glucopyranosid-6-yl orthoacetate) 9, respectively. The orthoesters were prepared from selective coupling of the disaccharide 3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -Glucopyranose 4 with ‘acetobromoglucose’ (tetra-O-acetyl-α- d -glucopyranosyl bromide) and 6-O-chloroacetylated ‘acetobromoglucose’, respectively. To confirm the selectivity of the orthoester formation and rearrangement, the disaccharide 4-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-1,2-O-(R,S)ethylidene-α- d -Glucopyranose 7 was prepared from 4 by selective tritylation, acetylation and detritylation. The title compound, an elicitor-active d -glucohexaose 3-O-(β- d -glucopyranosyl)-6-O-(6-O-(3,6-di-O-(β- d -glucopyranosyl)-β- d -glucopyranosyl)-β- d -glucopyranosyl)-α,β- d -Glucopyranose 1, was finally obtained by Zemplen deacetylation of 21 in quantitative yield.

Dina Keglevic - One of the best experts on this subject based on the ideXlab platform.

  • conformational analysis and computer modelling of muramic acid δ lactam structures
    1994
    Co-Authors: Zrinka Banic, Biserka Kojic Prodic, Loes M J Kroonbatenburg, Dina Keglevic
    Abstract:

    Abstract Conformational analysis of 1,6-anhydromuramic acid δ-lactam, muramic acid δ-lactam, and 1,6-anhydromuramic acid was studied by X-ray structure analysis, molecular mechanics and dynamics calculations, and computer modelling (BIOSYM package). The X-ray structure of 4-O-(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-1,6-anhydro-3-O-[(R)-1-car☐yethyl]-2-deoxy-β- d -Glucopyranose 1',2-lactam (1) was determined. The crystals of1 are monoclinic, space groupP21, with the unit cell parameters:a = 10.446(4),b = 4.891(1),c = 18.780(7)A˚; β = 94.33(2)°; andZ = 2. The stability of theBO,3 conformation of the β- d -Glucopyranose ring involved in the tricyclic structures of1 and 4-O-acetyl-2-amino-1,6-anhydro-3-O-[(R)-1-car☐yethyl]- 2-deoxy-β- d -Glucopyranose 1',2-lactam (2) was examined by computational chemistry methods. The influence of the 1,6-anhydro and δ-lactam rings on the conformation of the fused β- d -Glucopyranose component was studied by computer simulations performed on2. New compounds (3α,β and4) were generated from2 by opening of the 1,6-anhydro ring and cleavage of the δ-lactam ring, respectively. Conformational analysis of3α,β showed the minimum energy conformer of the d -Glucopyranose ring to be4C1, whereas a distorted chair/sofa conformation1C4/EO was obtained for4.

  • synthesis and conformational analysis of muramic acid δ lactam structures and their 4 o 2 acetamido 2 deoxy β d glucopyranosyl derivatives characteristic of bacterial spore peptidoglycan
    1993
    Co-Authors: Dina Keglevic, Biserka Kojicprodic, Zrinka Banic, Sanja Tomic, Vitomir Puntarec
    Abstract:

    Abstract 1,6-Anhydro-4- O -benzyl-β-muramic acid 1′,2-lactam ( 2 ) was prepared by reduction of 1,6-anhydro-2-azido-4- O -benzyl-2-deoxy-3- O -[( R )-1-methoxycarbonylethyl]-β- d -Glucopyranose ( 2 ) followed by cyclisation. Debenzylation of 2 ( → 3 ) and glycosylation of HO-4 with 3,4,6-tri- O -acetyl-2-deoxy-2-phthalimido-β- d -glucopyranosyl chloride afforded 75% of a β-(1 → 4)-linked disaccharide derivative ( 7 ). Removal of the Phth group from 7 , then acetylation, and O -deacetylation yielded 4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-1,6-anhydro-3- O -[( R )-1-carboxyethyl]-2-deoxy-β- d -Glucopyranose 1′,2-lactam ( 10 ) Acetolysis of the 1,6-anhydro ring in the 4-acetate ( 4 ) of 3 and the 3′,4′,6′-triacetate ( 9 ) of 10 , with saponification of the products 5 and 11 , afforded 2-amino-3- O -[( R )-1-carboxyethyl]-2-deoxy- d -Glucopyranose 1′,2-lactam ( 6 ) and 4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-3- O -[( R )-1-carboxyethyl]-2-deoxy-β- d - Glucopyranose 1′,2-lactam ( 12 ), respectively. The structure of 12 corresponds to that of the disaccharide unit characteristic of the glycan chains of bacterial spore peptidoglycan. 1 H NMR spectroscopy indicated that the β- d -Glucopyranose ring in the 1,6-anhydro 1′,2-lactam derivatives adopts the B O,3 conformation. On cleavage of the 1,6-anhydro ring by acetolysis, the d -Glucopyranose ring adopts the 4 C 1 conformation. X-ray analysis of 2 , 4 , and 5 confirmed the proposed structures. Molecular mechanics and molecular dynamics simulations were used to follow the transformation of the B O,3 conformation of the d -Glucopyranose ring via transition states to the 4 C 1 form.

Jun Ning - One of the best experts on this subject based on the ideXlab platform.

  • syntheses and reactions of 5 o acetyl 1 2 anhydro 3 o benzyl α d ribofuranose and β d lyxofuranose 5 o acetyl 1 2 anhydro 3 6 di o benzyl and 1 2 anhydro 5 6 di o benzoyl 3 o benzyl β d mannofuranose and 6 o acetyl 1 2 anhydro 3 4 di o benzyl α d Glucopyranose and β d talopyranose
    2001
    Co-Authors: Jun Ning, Fanzuo Kong
    Abstract:

    The title compounds 5-O-acetyl-1,2-anhydro-3-O-benzyl-alpha-D-ribofuranose and 5-O-acetyl-1,2-anhydro-3-O-benzyl-beta-D-lyxofuranose, and 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-alpha-D-Glucopyranose and 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-beta-D-talopyranose, and 5-O-acetyl-1,2-anhydro-3,6-di-O-benzyl-beta-D-mannofuranose and 1,2-anhydro-5,6-di-O-benzoyl-3-O-benzyl-beta-D-mannofuranose have each been synthesized from the corresponding 2-O-tosylate and 1-free hydroxyl intermediates by base-initiated intramolecular S(N)2 ring closure in almost quantitative yields. Acetyl and benzoyl groups were not affected in the ring closure reactions. Condensation of 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-alpha-D-Glucopyranose and 5-O-acetyl-1,2-anhydro-3,6-di-O-benzyl-beta-D-mannofuranose with 1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose in the presence of ZnCl2 as the catalyst afforded the 1,2-trans-linked 6-O-acetyl-3,4-di-O-benzyl-beta-D-glucopyranosyl-(1-->6)-1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose and 5-O-acetyl-3,6-di-O-benzyl-alpha-D-mannofuranosyl-(1-->6)-1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose as the sole products in satisfactory yields, while condensation of 5-O-acetyl-1,2-anhydro-3-O-benzyl-beta-D-lyxofuranose with 3-O-benzyl-1,2-O-isopropylidene-alpha-D-xylofuranose yielded the 1,2-trans-linked 5-O-acetyl-3-O-benzyl-alpha-D-lyxofuranosyl-(1-->5)-3-O-benzyl-1,2-O-isopropylidene-alpha-D-xylofuranose as the sole product in a good yield. The 6-O-acetyl group in the glycosyl donor, 6-O-acetyl-1,2-anhydro-3,4-di-O-benzyl-alpha-D-Glucopyranose, did not influence the stereoselectivity of the ring-opening-coupling reaction.

Zrinka Banic - One of the best experts on this subject based on the ideXlab platform.

  • conformational analysis and computer modelling of muramic acid δ lactam structures
    1994
    Co-Authors: Zrinka Banic, Biserka Kojic Prodic, Loes M J Kroonbatenburg, Dina Keglevic
    Abstract:

    Abstract Conformational analysis of 1,6-anhydromuramic acid δ-lactam, muramic acid δ-lactam, and 1,6-anhydromuramic acid was studied by X-ray structure analysis, molecular mechanics and dynamics calculations, and computer modelling (BIOSYM package). The X-ray structure of 4-O-(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-1,6-anhydro-3-O-[(R)-1-car☐yethyl]-2-deoxy-β- d -Glucopyranose 1',2-lactam (1) was determined. The crystals of1 are monoclinic, space groupP21, with the unit cell parameters:a = 10.446(4),b = 4.891(1),c = 18.780(7)A˚; β = 94.33(2)°; andZ = 2. The stability of theBO,3 conformation of the β- d -Glucopyranose ring involved in the tricyclic structures of1 and 4-O-acetyl-2-amino-1,6-anhydro-3-O-[(R)-1-car☐yethyl]- 2-deoxy-β- d -Glucopyranose 1',2-lactam (2) was examined by computational chemistry methods. The influence of the 1,6-anhydro and δ-lactam rings on the conformation of the fused β- d -Glucopyranose component was studied by computer simulations performed on2. New compounds (3α,β and4) were generated from2 by opening of the 1,6-anhydro ring and cleavage of the δ-lactam ring, respectively. Conformational analysis of3α,β showed the minimum energy conformer of the d -Glucopyranose ring to be4C1, whereas a distorted chair/sofa conformation1C4/EO was obtained for4.

  • synthesis and conformational analysis of muramic acid δ lactam structures and their 4 o 2 acetamido 2 deoxy β d glucopyranosyl derivatives characteristic of bacterial spore peptidoglycan
    1993
    Co-Authors: Dina Keglevic, Biserka Kojicprodic, Zrinka Banic, Sanja Tomic, Vitomir Puntarec
    Abstract:

    Abstract 1,6-Anhydro-4- O -benzyl-β-muramic acid 1′,2-lactam ( 2 ) was prepared by reduction of 1,6-anhydro-2-azido-4- O -benzyl-2-deoxy-3- O -[( R )-1-methoxycarbonylethyl]-β- d -Glucopyranose ( 2 ) followed by cyclisation. Debenzylation of 2 ( → 3 ) and glycosylation of HO-4 with 3,4,6-tri- O -acetyl-2-deoxy-2-phthalimido-β- d -glucopyranosyl chloride afforded 75% of a β-(1 → 4)-linked disaccharide derivative ( 7 ). Removal of the Phth group from 7 , then acetylation, and O -deacetylation yielded 4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-1,6-anhydro-3- O -[( R )-1-carboxyethyl]-2-deoxy-β- d -Glucopyranose 1′,2-lactam ( 10 ) Acetolysis of the 1,6-anhydro ring in the 4-acetate ( 4 ) of 3 and the 3′,4′,6′-triacetate ( 9 ) of 10 , with saponification of the products 5 and 11 , afforded 2-amino-3- O -[( R )-1-carboxyethyl]-2-deoxy- d -Glucopyranose 1′,2-lactam ( 6 ) and 4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-3- O -[( R )-1-carboxyethyl]-2-deoxy-β- d - Glucopyranose 1′,2-lactam ( 12 ), respectively. The structure of 12 corresponds to that of the disaccharide unit characteristic of the glycan chains of bacterial spore peptidoglycan. 1 H NMR spectroscopy indicated that the β- d -Glucopyranose ring in the 1,6-anhydro 1′,2-lactam derivatives adopts the B O,3 conformation. On cleavage of the 1,6-anhydro ring by acetolysis, the d -Glucopyranose ring adopts the 4 C 1 conformation. X-ray analysis of 2 , 4 , and 5 confirmed the proposed structures. Molecular mechanics and molecular dynamics simulations were used to follow the transformation of the B O,3 conformation of the d -Glucopyranose ring via transition states to the 4 C 1 form.

Vitomir Puntarec - One of the best experts on this subject based on the ideXlab platform.

  • synthesis and conformational analysis of muramic acid δ lactam structures and their 4 o 2 acetamido 2 deoxy β d glucopyranosyl derivatives characteristic of bacterial spore peptidoglycan
    1993
    Co-Authors: Dina Keglevic, Biserka Kojicprodic, Zrinka Banic, Sanja Tomic, Vitomir Puntarec
    Abstract:

    Abstract 1,6-Anhydro-4- O -benzyl-β-muramic acid 1′,2-lactam ( 2 ) was prepared by reduction of 1,6-anhydro-2-azido-4- O -benzyl-2-deoxy-3- O -[( R )-1-methoxycarbonylethyl]-β- d -Glucopyranose ( 2 ) followed by cyclisation. Debenzylation of 2 ( → 3 ) and glycosylation of HO-4 with 3,4,6-tri- O -acetyl-2-deoxy-2-phthalimido-β- d -glucopyranosyl chloride afforded 75% of a β-(1 → 4)-linked disaccharide derivative ( 7 ). Removal of the Phth group from 7 , then acetylation, and O -deacetylation yielded 4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-1,6-anhydro-3- O -[( R )-1-carboxyethyl]-2-deoxy-β- d -Glucopyranose 1′,2-lactam ( 10 ) Acetolysis of the 1,6-anhydro ring in the 4-acetate ( 4 ) of 3 and the 3′,4′,6′-triacetate ( 9 ) of 10 , with saponification of the products 5 and 11 , afforded 2-amino-3- O -[( R )-1-carboxyethyl]-2-deoxy- d -Glucopyranose 1′,2-lactam ( 6 ) and 4- O -(2-acetamido-2-deoxy-β- d -glucopyranosyl)-2-amino-3- O -[( R )-1-carboxyethyl]-2-deoxy-β- d - Glucopyranose 1′,2-lactam ( 12 ), respectively. The structure of 12 corresponds to that of the disaccharide unit characteristic of the glycan chains of bacterial spore peptidoglycan. 1 H NMR spectroscopy indicated that the β- d -Glucopyranose ring in the 1,6-anhydro 1′,2-lactam derivatives adopts the B O,3 conformation. On cleavage of the 1,6-anhydro ring by acetolysis, the d -Glucopyranose ring adopts the 4 C 1 conformation. X-ray analysis of 2 , 4 , and 5 confirmed the proposed structures. Molecular mechanics and molecular dynamics simulations were used to follow the transformation of the B O,3 conformation of the d -Glucopyranose ring via transition states to the 4 C 1 form.

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