14155-23-8Relevant articles and documents
Kondo
, p. 386,388 (1973)
A practical synthesis of methyl 4,6-O-benzylidene-α- and β-D-glucopyranoside
Hall, David M.
, p. 158 - 160 (1980)
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Acceleration and deceleration factors on the hydrolysis reaction of 4,6-O-benzylidene acetal group
Maki, Yuta,Kajihara, Yasuhiro,Nomura, Kota,Okamoto, Ryo,Izumi, Masayuki,Mizutani, Yasuhisa
, p. 15849 - 15856 (2021/01/18)
The benzylidene acetal group is one of the most important protecting groups not only in carbohydrate chemistry but also in general organic chemistry. In the case of 4,6-O-benzylidene glycosides, we previously found that the stereochemistry at 4-position altered the reaction rate constant for hydrolysis of benzylidene acetal group. However, a detail of the acceleration or deceleration factor was still unclear. In this work, the hydrolysis reaction of benzylidene acetal group was analyzed using the Arrhenius and Eyring plot to obtain individual parameters for glucosides (Glc), mannosides (Man), and galactosides (Gal). The Arrhenius and Eyring plot indicated that the pre-exponential factor (A) and ΔS? were critical for the smallest reaction rate constant of Gal among nonacetylated substrates. On the other hand, both Ea/ΔH? and A/ΔS? were influential for the smallest reaction rate constant of Gal among diacetylated substrates. All parameters obtained suggested that the rate constant for hydrolysis reaction was regulated by protonation and hydration steps along with solvation. The obtained parameters support wide use of benzylidene acetal group as orthogonal protection of cis- and trans-fused bicyclic systems through the fast hydrolysis of the trans-fused benzylidene acetal group.
Synthesis and O-Glycosidic Linkage Conformational Analysis of 13C-Labeled Oligosaccharide Fragments of an Antifreeze Glycolipid
Zhang, Wenhui,Meredith, Reagan,Yoon, Mi-Kyung,Wang, Xiaocong,Woods, Robert J.,Carmichael, Ian,Serianni, Anthony S.
, p. 1706 - 1724 (2019/02/14)
NMR studies of two 13C-labeled disaccharides and a tetrasaccharide were undertaken that comprise the backbone of a novel thermal hysteresis glycolipid containing a linear glycan sequence of alternating [βXylp-(1→4)-βManp-(1→4)]n dimers. Experimental trans-glycoside NMR J-couplings, parameterized equations obtained from density functional theory (DFT) calculations, and an in-house circular statistics package (MA'AT) were used to derive conformational models of linkage torsion angles φ and ψ in solution, which were compared to those obtained from molecular dynamics simulations. Modeling using different probability distribution functions showed that MA'AT models of φ in βMan(1→4)βXyl and βXyl(1→4)βMan linkages are very similar in the disaccharide building blocks, whereas MA'AT models of ψ differ. This pattern is conserved in the tetrasaccharide, showing that linkage context does not influence linkage geometry in this linear system. Good agreement was observed between the MA'AT and MD models of ψ with respect to mean values and circular standard deviations. Significant differences were observed for φ, indicating that revision of the force-field employed by GLYCAM is probably needed. Incorporation of the experimental models of φ and ψ into the backbone of an octasaccharide fragment leads to a helical amphipathic topography that may affect the thermal hysteresis properties of the glycolipid.
