Oxazoline synthesis of 1,2-trans-2-acetamido-2-deoxyglycosides. Glycosylation of secondary hydroxyl groups in partially protected saccharides

Zurabyan, S. E.; Antonenko, T. S.; Khorlin, A. Ya.

doi:10.1016/s0008-6215(00)80289-x

Cited by 54 publications

(11 citation statements)

References 16 publications

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“…33−35 Literature search of the triterpene skeleton bearing the α,β-dimethyl α,βunsaturated γ-lactone fragment showed a similar structure to that of inotolactone A, isolated from the mushroom Inonotus obliquus. 36 Comparison of the 1 H and 13 C NMR data of 28 with those of inotolactone A suggests the presence of one additional hydroxyl group in 28. This agrees with the molecular mass difference of 16 mass units between the aglycon of 28 and that of inotolactone A.…”

Section: Enzymatic Inhibition Bioassaysmentioning

confidence: 99%

“…NOE correlations observed for the aglycone are in agreement to those found in similar triterpenoids (Figure S15). 36 The relative configuration between stereocenters at C-20 and C-22 in the side chain of 28 was determined by NOESY and DP4+ statistical analysis based on DFT NMR calculations made for the two possible epimers at C-22. The observed NOE correlations among protons H-22, H-16a, and H-17 in the NOESY experiment allowed us to place all these protons on the same face (α-face).…”

Section: Enzymatic Inhibition Bioassaysmentioning

confidence: 99%

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Identification of α-Amylase and α-Glucosidase Inhibitors and Ligularoside A, a New Triterpenoid Saponin from Passiflora ligularis Juss (Sweet Granadilla) Leaves, by a Nuclear Magnetic Resonance-Based Metabolomic Study

Daza

Macías

Forero

et al. 2021

J. Agric. Food Chem.

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The leaves of Passiflora ligularis Juss (known as sweet granadilla for its edible fruits) are a crop byproduct that is discarded. With the aim of contributing to give value-added products from these crop by-side products to farmers of Colombian Andes, we carried out a 1H-NMR-metabolomics analysis of polar extracts from leaves collected in three locations and stored in two conditions in order to identify glucosyl-hydrolase inhibitors. Variations in the metabolic profile and the bioactivity among samples were analyzed by orthogonal partial least square discriminant analysis. Thus, 1H-NMR signals related to polyphenolic compounds, saponins, and amino acids were correlated with higher inhibitory activities. Moreover, a targeted NMR and HPLC–MS/MS analysis allowed the identification of 14 polyphenolic compounds and the structural characterization of a new triterpenoid saponin, ligularoside A. The measurements of IC50 values for α-amylase and α-glycosidase inhibitors allowed the identification of quercetin-3-O-β-glucoside, kaempferol-3-O-β-glucoside, and ligularoside A as the most active compounds. These results suggest that P. ligularis leaves are a source of glucosyl-hydrolase inhibitors and lay the foundation for exploring additional applications.

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Section: Enzymatic Inhibition Bioassaysmentioning

confidence: 99%

Section: Enzymatic Inhibition Bioassaysmentioning

confidence: 99%

Identification of α-Amylase and α-Glucosidase Inhibitors and Ligularoside A, a New Triterpenoid Saponin from Passiflora ligularis Juss (Sweet Granadilla) Leaves, by a Nuclear Magnetic Resonance-Based Metabolomic Study

Daza

Macías

Forero

et al. 2021

J. Agric. Food Chem.

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“…Further, Oxazolines, which are five member nitrogen and oxygen‐containing heterocycles with one double bond, are also known to exhibit diverse biological activities in various diseases and serve several functions in synthetic organic chemistry such as chiral auxallaries, metal trappers and protecting groups [15–18] . Spoxazomicin D, an oxazoline containg carboxamide from microbial origin reportedly show strong neuroprotective activity [19] .…”

Section: Figurementioning

confidence: 99%

Sulphonamide‐Containing Oxazoline Hybrids as New Class of Neuroprotective Agents and Lead Molecule as Autophagy Inducer

et al. 2021

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Sulphonamide derived oxazoline hybrid compounds showed neuroprotective effects by inducing autophagy. In the present study, a series of sulphonamide containing oxazoline hybrids were synthesized and their neuroprotective efficacy in neuronal cell lines was explored. All the compounds showed moderate to good neuroprotection against adrenal medulla cell lines (PC 12). Compound 6 j had good neuroprotective activity against PC 12 cell lines showing increased expression of autophagy regulatory proteins (ATG7, LC 3B, p62, Beclin‐1) and anti‐apoptotic proteins (Bcl‐2) and also decreased expression of pro‐apoptotic proteins (Bax and Bad). This study demonstrated clearly that compound 6 j showed neuroprotective effect through the induction of autophagy and opens up new avenues for a new class of compounds as neuroprotective therapeutic agents.

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“…Though the majority of synthetic work focussed on production and reaction of gluco -configured oxazolines (i.e., those derived from GlcNAc), the corresponding manno [ 10 – 11 ] and galacto -configured [ 12 ] compounds have also been made and studied. Although the first generation of these oxazoline donors [ 13 – 14 ] proved to be rather unreactive, and found only limited applications [ 15 – 18 ], the addition of three chlorines to the methyl group did increase their potency [ 19 – 23 ]. However, applications were still less widespread than more conventional glucosamine-derived donors.…”

Section: Reviewmentioning

confidence: 99%

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

Fairbanks

2018

Beilstein J. Org. Chem.

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N-Glycan oxazolines have found widespread use as activated donor substrates for endo-β-N-acetylglucosaminidase (ENGase) enzymes, an important application that has correspondingly stimulated interest in their production, both by total synthesis and by semi-synthesis using oligosaccharides isolated from natural sources. Amongst the many synthetic approaches reported, the majority rely on the fabrication (either by total synthesis, or semi-synthesis from locust bean gum) of a key Manβ(1–4)GlcNAc disaccharide, which can then be elaborated at the 3- and 6-positions of the mannose unit using standard glycosylation chemistry. Early approaches subsequently relied on the Lewis acid catalysed conversion of peracetylated N-glycan oligosaccharides produced in this manner into their corresponding oxazolines, followed by global deprotection. However, a key breakthrough in the field has been the development by Shoda of 2-chloro-1,3-dimethylimidazolinium chloride (DMC), and related reagents, which can direct convert an oligosaccharide with a 2-acetamido sugar at the reducing terminus directly into the corresponding oxazoline in water. Therefore, oxazoline formation can now be achieved in water as the final step of any synthetic sequence, obviating the need for any further protecting group manipulations, and simplifying synthetic strategies. As an alternative to total synthesis, significant quantities of several structurally complicated N-glycans can be isolated from natural sources, such as egg yolks and soy bean flour. Enzymatic transformations of these materials, in concert with DMC-mediated oxazoline formation as a final step, allow access to a selection of N-glycan oxazoline structures both in larger quantities and in a more expedient fashion than is achievable by total synthesis.

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Oxazoline synthesis of 1,2-trans-2-acetamido-2-deoxyglycosides. Glycosylation of secondary hydroxyl groups in partially protected saccharides

Cited by 54 publications

References 16 publications

Identification of α-Amylase and α-Glucosidase Inhibitors and Ligularoside A, a New Triterpenoid Saponin from Passiflora ligularis Juss (Sweet Granadilla) Leaves, by a Nuclear Magnetic Resonance-Based Metabolomic Study

Identification of α-Amylase and α-Glucosidase Inhibitors and Ligularoside A, a New Triterpenoid Saponin from Passiflora ligularis Juss (Sweet Granadilla) Leaves, by a Nuclear Magnetic Resonance-Based Metabolomic Study

Sulphonamide‐Containing Oxazoline Hybrids as New Class of Neuroprotective Agents and Lead Molecule as Autophagy Inducer

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

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