Inna S. Popova

Toward creating cell membrane glyco-landscapes with glycan lipid constructs

Synthetic glycolipid-like constructs dispersible in biological media and capable of incorporating into cell membranes have the ability to create novel artificial glyco-landscapes on living cells. Using a variety of different glycans ranging from disaccharides to polysaccharides, together with different lengths and high hydrophilicity spacers, we created a series of synthetic glycolipid-like constructs. Contacting these constructs with live cells gave modified cells with controlled glycan density and/or altered biological function. The ability to also use these constructs as solutions to inhibit antibodies, toxins, and virions extends the potential diagnostic and therapeutic uses for these synthetic glycolipid-like constructs.

Block synthesis of A tetrasaccharides (types 1, 3, and 4) related to the human ABO blood group system.

Blood group A tetrasaccharides of different types have the same terminal trisaccharide fragment that allows using a block scheme in their synthesis. 3-Aminopropyl glycosides of tetrasaccharides GalNAcα1-3(Fucα1-2)Galβ1-3GlcNAcβ (A type 1), GalNAcα1-3(Fucα1-2)Galβ1-3GalNAcα (A type 3), and GalNAcα1-3(Fucα1-2)Galβ1-3GalNAcβ (A type 4) were synthesised using acetylated Galα1-3(Fucα1-2)Gal trichloroacetimidate as a glycosyl donor at the key stage.

Monoclonal anti-A activity against the FORS1 (Forssman) antigen

The FORS blood group system (originally recognized as the Apae phenotype) was discovered by sporadic activity against polyclonal anti‐A reagents and activity against the lectin Helix pomatia. The extent of monoclonal anti‐A reagent activity against the FORS1 antigen is serologically and immunochemically incomplete.

Block synthesis of A (type 2) and B (type 2) tetrasaccharides related to the human ABO blood group system.

Herein we report the synthesis of 3-aminopropyl glycosides of A (type 2) and B (type 2) tetrasaccharides via [3 + 1] block scheme. Peracetylated trichloroacetimidates of A and B trisaccharides were used as glycosyl donors. The well-known low reactivity of 4-OH group of N-acetyl-d-glucosamine forced us to test four glucosamine derivatives (3-Bz-1,6-anhydro-GlcNAc and 3-trifluoroacetamidopropyl β-glycosides of 3-Ac-6-Bn-GlcNAc, 3-Ac-6-Bn-GlcN3, and 3-Ac-6-Bn-GlcNAc2) to select the best glycosyl acceptor for the synthesis of type 2 tetrasaccharides. The desired tetrasacchrides were not isolated, when 3-trifluoroacetamidopropyl glycosyde of 3-Ac-6-Bn-GlcNAcβ was glycosylated. Glycosylation of 3-Bz-1,6-anhydro-GlcNAc derivative resulted in α-glycoside as a major product. High stereospecificity was achieved only in the synthesis of B (type 2) tetrasaccharide, when 3-trifluoroacetamidopropyl 3-Ac-6-Bn-GlcNAc2β was applied as the glycosyl acceptor (β/α 5:1), whereas glycosylation with trichloroacetimidate of A trisaccharide was not stereospecific (β/α 1.3:1). Glycosylation of 3-trifluoroacetamidopropyl glycoside of 3-Ac-6-Bn-GlcN3β with trichloroacetimidates of A and B trisaccharides provided the same stereochemical yield (β/α 1.5:1).

The Total Large-Scale Synthesis of Argiopine

The total large-scale synthesis of a natural toxin argiopine, a polymethylenepolyamine derivative, was developed. It consisted of 26 stages and included three key block schemes. Most of the stages proceeded quantitatively, which excluded the necessity of using the chromatographic separation of intermediates.

Biofunctionalizing nanofibers with carbohydrate blood group antigens

A rapid and simple method of biofunctionalising nylon, cellulose acetate, and polyvinyl butyral electrospun nanofibers with blood group glycans was achieved by preparing function‐spacer‐lipid constructs and simply contacting them to fibers with a piezo inkjet printer. A series of water dispersible amphipathic glycan‐spacer constructs were synthesized representing a range ABO and related blood group antigens. After immediate contact of the amphipathic glycan‐spacer constructs with nanofiber surfaces they self‐assembled and were detectable by enzyme immunoassays with high sensitivity and specificity.

Use of a Metallation Reaction to Obtain Substituted 2-(5-Methyl-2-thiazolyl)ethanols

The interaction of anions, obtained by treating 2,4,5-trimethylthiazole and 2,5-dimethyl-4-phenylthiazole with butyllithium, with aliphatic and aromatic aldehydes leads to substituted 2-thiazolyl-1-ethanols. It was established that the metallation reaction occurs at the 2-methyl group of the thiazoles.

Characteristics of the synthesis of substituted and condensed 2-methyl-1,3-diazoles

Condensation of aliphatic and carbocyclic α-bromo ketones with thioacetamide in ethanol usually leads to substituted or condensed 2-methyl-1,3-thiazoles. However in a number of cases the required compounds are only obtained in pyridine.