Jevgeņija Lugiņina

On Moffatt dehydration of glucose-derived nitro alcohols

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.

Non-activated aziridines as building blocks for the synthesis of aza-heterocycles (microreview)

This microreview deals with ring opening reactions of non-activated aziridines and their applications in heterocycle synthesis. Only recent methods published in the last five years are discussed.

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

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.

Synthesis and Antibacterial Activity of 5-Phthalate and 5-Glutarate Derivatives of Milbemycins A 3 /A 4 *

Naturally occurring 16-membered macrolides milbemycins A3 and A4 were selectively esterified at their 5-OH group with phthalic and glutaric anhydrides. The obtained monoesters were further functionalized by amide formation. Propargylamide derivatives were demonstrated to undergo 1,2,3-triazole formation upon treatment with organic azides in the presence of copper catalyst. Some of the synthesized compounds exhibited useful levels of antibacterial properties against Staphylococcus aureus and Staphylococcus epidermidis.

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

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.

Stereoselective Michael addition of O-nucleophiles to carbohydrate-based nitro-olefin

Abstract Michael addition reactions of O-nucleophiles to C(3) exocyclic nitromethylene derivative of diacetone glucose are reported. The reactions with primary alcohols proceed at ambient temperature in the presence of different bases with good yields and give products with excellent diastereoselectivity. The addition of the nucleophile occurs from the β-face of the carbohydrate as shown by single crystal X-ray analysis. The reactions with secondary alcohols give low yields of products while phenolic compounds do not react. Under certain conditions, isomerization of starting material is observed.

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

The title compound, a nitro carbohydrate, consists of a substituted 2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxolane skeleton. The furanose ring adopts a oT 4 conformation.