Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors
In a previous paper (Bohn et al., Carbohydr. Res., 2007, 342, 2522) the relative O3/O4 reactivities of both α- and β-methyl glycosides of N-dimethylmaleoyl (DMM) glucosamine acceptors protected at O6 with three different groups were assessed by us, using two glycosyl donors. The α-anomers showed pre...
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todo:paper_14770520_v6_n3_p554_Bohn2023-10-03T16:19:07Z Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors Bohn, M.L. Colombo, M.I. Rúveda, E.A. Stortz, C.A. Aromatic polymers Conformations Electronic structure Glycosylation Regioselectivity Substitution reactions Glycosyl donors N-dimethylmaleoyl (DMM) glucosamine acceptors Amines drug derivative glucosamine oxygen article chemical structure chemistry conformation electron enzyme specificity glycosylation hydrogen bond mechanical torsion metabolism nomenclature rotation stereoisomerism thermodynamics Carbohydrate Conformation Electrons Glucosamine Glycosylation Hydrogen Bonding Models, Molecular Oxygen Rotation Stereoisomerism Substrate Specificity Terminology as Topic Thermodynamics Torsion, Mechanical In a previous paper (Bohn et al., Carbohydr. Res., 2007, 342, 2522) the relative O3/O4 reactivities of both α- and β-methyl glycosides of N-dimethylmaleoyl (DMM) glucosamine acceptors protected at O6 with three different groups were assessed by us, using two glycosyl donors. The α-anomers showed preferential or exclusive substitution at O3, whereas the β-anomers gave preferential or exclusive substitution at O4. A DFT study of analogs of the reported acceptors indicates that whereas the β-anomers carry the DMM ring parallel to the C2-H2 bond for steric reasons, the α-anomers tilt this ring producing a strong hydrogen bond between the H(O)3 and one of the DMM carbonyl groups. In this way, the O3 group becomes more nucleophilic and thus more reactive: both charge and Fukui functions on O3 and O4 in the model compounds support the experimental results. Surprisingly, the previously mentioned hydrogen bond is not the only driving force for the slant of the DMM group: the axial methoxyl group of the α-anomers also plays a role. The ease of rotation around the C2-N2 bond for DMM-protected analogs was assessed with different models. MP2 calculations using higher basis sets yield similar relative energy and charge values to those calculated using DFT. © The Royal Society of Chemistry 2008. Fil:Stortz, C.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_14770520_v6_n3_p554_Bohn |
| institution |
Universidad de Buenos Aires |
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I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Aromatic polymers Conformations Electronic structure Glycosylation Regioselectivity Substitution reactions Glycosyl donors N-dimethylmaleoyl (DMM) glucosamine acceptors Amines drug derivative glucosamine oxygen article chemical structure chemistry conformation electron enzyme specificity glycosylation hydrogen bond mechanical torsion metabolism nomenclature rotation stereoisomerism thermodynamics Carbohydrate Conformation Electrons Glucosamine Glycosylation Hydrogen Bonding Models, Molecular Oxygen Rotation Stereoisomerism Substrate Specificity Terminology as Topic Thermodynamics Torsion, Mechanical |
| spellingShingle |
Aromatic polymers Conformations Electronic structure Glycosylation Regioselectivity Substitution reactions Glycosyl donors N-dimethylmaleoyl (DMM) glucosamine acceptors Amines drug derivative glucosamine oxygen article chemical structure chemistry conformation electron enzyme specificity glycosylation hydrogen bond mechanical torsion metabolism nomenclature rotation stereoisomerism thermodynamics Carbohydrate Conformation Electrons Glucosamine Glycosylation Hydrogen Bonding Models, Molecular Oxygen Rotation Stereoisomerism Substrate Specificity Terminology as Topic Thermodynamics Torsion, Mechanical Bohn, M.L. Colombo, M.I. Rúveda, E.A. Stortz, C.A. Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors |
| topic_facet |
Aromatic polymers Conformations Electronic structure Glycosylation Regioselectivity Substitution reactions Glycosyl donors N-dimethylmaleoyl (DMM) glucosamine acceptors Amines drug derivative glucosamine oxygen article chemical structure chemistry conformation electron enzyme specificity glycosylation hydrogen bond mechanical torsion metabolism nomenclature rotation stereoisomerism thermodynamics Carbohydrate Conformation Electrons Glucosamine Glycosylation Hydrogen Bonding Models, Molecular Oxygen Rotation Stereoisomerism Substrate Specificity Terminology as Topic Thermodynamics Torsion, Mechanical |
| description |
In a previous paper (Bohn et al., Carbohydr. Res., 2007, 342, 2522) the relative O3/O4 reactivities of both α- and β-methyl glycosides of N-dimethylmaleoyl (DMM) glucosamine acceptors protected at O6 with three different groups were assessed by us, using two glycosyl donors. The α-anomers showed preferential or exclusive substitution at O3, whereas the β-anomers gave preferential or exclusive substitution at O4. A DFT study of analogs of the reported acceptors indicates that whereas the β-anomers carry the DMM ring parallel to the C2-H2 bond for steric reasons, the α-anomers tilt this ring producing a strong hydrogen bond between the H(O)3 and one of the DMM carbonyl groups. In this way, the O3 group becomes more nucleophilic and thus more reactive: both charge and Fukui functions on O3 and O4 in the model compounds support the experimental results. Surprisingly, the previously mentioned hydrogen bond is not the only driving force for the slant of the DMM group: the axial methoxyl group of the α-anomers also plays a role. The ease of rotation around the C2-N2 bond for DMM-protected analogs was assessed with different models. MP2 calculations using higher basis sets yield similar relative energy and charge values to those calculated using DFT. © The Royal Society of Chemistry 2008. |
| format |
JOUR |
| author |
Bohn, M.L. Colombo, M.I. Rúveda, E.A. Stortz, C.A. |
| author_facet |
Bohn, M.L. Colombo, M.I. Rúveda, E.A. Stortz, C.A. |
| author_sort |
Bohn, M.L. |
| title |
Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors |
| title_short |
Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors |
| title_full |
Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors |
| title_fullStr |
Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors |
| title_full_unstemmed |
Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors |
| title_sort |
conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of n-dimethylmaleoyl-protected glucosamine acceptors |
| url |
http://hdl.handle.net/20.500.12110/paper_14770520_v6_n3_p554_Bohn |
| work_keys_str_mv |
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