Publications by authors named "Jevgeņija Lugiņina"

6 Publications

  • Page 1 of 1

Metal-free glycosylation with glycosyl fluorides in liquid SO.

Beilstein J Org Chem 2021 29;17:964-976. Epub 2021 Apr 29.

Institute of Technology of Organic Chemistry, Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena str. 3, Riga, LV-1048, Latvia.

Liquid SO is a polar solvent that dissolves both covalent and ionic compounds. Sulfur dioxide possesses also Lewis acid properties, including the ability to covalently bind Lewis basic fluoride ions in a relatively stable fluorosulfite anion (FSO). Herein we report the application of liquid SO as a promoting solvent for glycosylation with glycosyl fluorides without any external additive. By using various temperature regimes, the method is applied for both armed and disarmed glucose and mannose-derived glycosyl fluorides in moderate to excellent yields. A series of pivaloyl-protected - and -mannosides, as well as one example of a -mannoside, are synthesized to demonstrate the scope of the glycosyl acceptors. The formation of the fluorosulfite species during the glycosylation with glycosyl fluorides in liquid SO is proved by F NMR spectroscopy. A sulfur dioxide-assisted glycosylation mechanism that proceeds via solvent separated ion pairs is proposed, whereas the observed α,β-selectivity is substrate-controlled and depends on the thermodynamic equilibrium.
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http://dx.doi.org/10.3762/bjoc.17.78DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8093551PMC
April 2021

Anticancer Potential of Betulonic Acid Derivatives.

Int J Mol Sci 2021 Apr 1;22(7). Epub 2021 Apr 1.

Department of Pharmacognosy, "Victor Babes" University of Medicine and Pharmacy, Eftimie Murgu Square, No. 2, 300041 Timisoara, Romania.

Clinical trials have evidenced that several natural compounds, belonging to the phytochemical classes of alkaloids, terpenes, phenols and flavonoids, are effective for the management of various types of cancer. Latest research has proven that natural products and their semisynthetic variants may serve as a starting point for new drug candidates with a diversity of biological and pharmacological activities, designed to improve bioavailability, overcome cellular resistance, and enhance therapeutic efficacy. This review was designed to bring an update regarding the anticancer potential of betulonic acid and its semisynthetic derivatives. Chemical derivative structures of betulonic acid including amide, thiol, and piperidine groups, exert an amplification of the in vitro anticancer potential of betulonic acid. With the need for more mechanistic and in vivo data, some derivatives of betulonic acids may represent promising anticancer agents.
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http://dx.doi.org/10.3390/ijms22073676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8037575PMC
April 2021

Synthesis and Immunological Evaluation of Virus-Like Particle-Milbemycin A₃/A₄ Conjugates.

Antibiotics (Basel) 2017 Sep 11;6(3). Epub 2017 Sep 11.

PharmIdea Ltd., Rupnicu 4, Olaine, Riga District, LV-2114 Olaine, Latvia.

Milbemycins are macrolide antibiotics with a broad spectrum of nematocidal, insecticidal, and acaricidal activity. To obtain milbemycin A₃/A₄ derivatives suitable for chemical conjugation to protein carriers (milbemycin haptens), succinate linker and a novel 17-atom-long linker containing a terminal carboxylic acid group were attached to the milbemycin core in a protecting group-free synthesis. The obtained milbemycin A₃/A₄ derivatives were coupled to Potato virus Y-like nanoparticles by the activated ester method. The reaction products were characterized and used in mice immunization experiments. It was found that the mice developed weak specific immune responses toward all tested milbemycin haptens.
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http://dx.doi.org/10.3390/antibiotics6030018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617982PMC
September 2017

Crystal structure of 3-de-oxy-3-nitro-methyl-1,2;5,6-di-O-iso-propyl-idene-α-d-allo-furan-ose.

Acta Crystallogr E Crystallogr Commun 2016 Mar 10;72(Pt 3):314-7. Epub 2016 Feb 10.

Latvian Institute of Organic Synthesis, Str. Aizkraukles 21, Riga, LV 1006, Latvia.

The title compound, C13H21NO7 {systematic name: (3aR,5S,6R,6aR)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-6-(nitro-meth-yl)tetra-hydro-furo[2,3-d][1,3]dioxole}, consists of a substituted 2,2-di-methyl-tetra-hydro-furo[2,3-d][1,3]dioxolane skeleton. The furan-ose ring A adopts a (o)T 4 conformation. The fused dioxolane ring B and the substituent dioxolane ring C also have twisted conformations. There are no strong hydrogen bonds in the crystal structure: only weak C-H⋯O contacts are present, which link the mol-ecules to form a three-dimensional structure.
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http://dx.doi.org/10.1107/S2056989016001845DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4778814PMC
March 2016

Synthesis and X-ray studies of novel 3-C-nitromethyl-hexofuranoses.

Carbohydr Res 2014 Jun 12;391:82-8. Epub 2014 Mar 12.

Department of Biotechnology, University of Rijeka, Trg braće Mažuranića 10, 51000 Rijeka, Croatia.

A practical method for the synthesis of three novel 3-C-nitromethyl-hexofuranoses is reported. The Henry reaction on a 1,2:5,6-di-O-isopropylidene-α-d-gulofuranose-derived ketone provided a 3-C-branched gulo-isomer as the sole reaction product. The dehydration-rehydration of the latter yielded an isopropylidene-protected 3-C-nitromethyl-galactofuranose. The reaction sequence can be also used for the synthesis of a 3-deoxy-3-C-nitromethyl-hexofuranose derivative with a gulo-configuration. Two of the newly obtained carbohydrate derivatives were characterized by X-ray crystallography.
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http://dx.doi.org/10.1016/j.carres.2014.03.003DOI Listing
June 2014

On Moffatt dehydration of glucose-derived nitro alcohols.

Carbohydr Res 2012 Mar 29;350:86-9. Epub 2011 Dec 29.

Faculty of Material Science and Applied Chemistry, Riga Technical University, 14/24 Azenes Str., Riga, Latvia.

Moffatt dehydration of 1,2:5,6-di-O-isopropylidene-α-d-glucofuranose derived nitro alcohols with a mixture of Ac(2)O and DMSO was reinvestigated. It was discovered that, regardless of the absolute configuration at C(3) of the sugar moiety, the dehydration provided exclusively the (3Z)-nitromethylene derivative. Slight modification of the workup conditions (pH⩾8, temperature: 25-30°C) gave exclusively a novel product, (3S)-3-deoxy-3-methylthio-3-C-nitromethyl-1,2:5,6-di-O-isopropylidene-α-d-glucofuranose. The latter was obtained by a Michael addition of thiomethylate anion to the previously reported nitromethylene derivative during the aqueous basic workup at ambient or slightly elevated temperature. The putative mechanism leading to the thiomethylate anion includes Pummerer rearrangement of DMSO and basic hydrolysis of thus formed methylsulfanylmethyl acetate.
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http://dx.doi.org/10.1016/j.carres.2011.12.020DOI Listing
March 2012