Synthesis and properties of thiazole halohydrazones. 2. Interaction of 2-α-chlorobenzylidenehydrazino-4-ethoxy-carbonylthiazole with nucleophiles

In the interaction of 2--clzlorobenzylidenehydrazino-4-ethoxycarbonylthiazole with nucleophiles, two competing reactions take place. 1) nucleophilic replacement of the chlorine atom to form the corresponding substitution product; 2) elimination of a hydrogen chloride molecule, concluding in cyclization of the intermediate nitrilimine to form 3 phenyl-5-ethoxycarbonylthiazolo(2, 3-c]-1, 2, 4-triazole. The direction taken by the interaction depends on the nature of the nucleophile and is determined primarily by the ratio of basicity and nucleophilicity of the agent.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, 256–259, February, 1994. Original article submitted December 30, 1993.     

A simple nitration of electrophilic alkenes with tetranitromethane in the presence of triethylamine. Synthesis of functionalized β-nitroalkenes

A convenient method for the preparation of functionalized β-nitroalkenes based on the nitration of α,α-di- and α,α,β-trisubstituted unsaturated aldehydes, ketones and esters with tetranitromethane in the presence of triethylamine is described. Series of substituted β-nitroalcohols and β-nitroalkenes are obtained in good yields under mild conditions.     

Ring opening of aziridines with tetranitromethane in the presence of triethylamine. Efficient synthesis of β-tosylamino nitrates

A convenient method for the preparation of β-tosylamino nitrates based on the ring-opening reaction of aziridines by tetranitromethane in the presence of triethylamine is described. A series of substituted β-amino nitrates is obtained in high yields under mild conditions.     

Synthesis and Molecular Structure of 4-Chloromethyl-3-anilino-2-（4- methylbenzoylimido）thiazole

The title compound 2, 4-chloromethyl-3-anilino-2-（4-methyl-benzoylimido）thiazole, was prepared by the reaction of 1-p-methylbenzoyl-3-phenylaminothiourea 1 with 1,3-dichloro- acetone. The crystal is of monoclinic, space group P21/c, with a = 8.1712（15）, b = 10.998（2）, c = 19.134（4）A, β= 94.610（5）°, C18H16ClN3OS, Mr = 357.85, Z = 4, V = 1714.0（6）A^3, De= 1.387 g/cm^3, μ（MoKa） = 0.354 mm^-1, F（000） = 744, the final R = 0.0518 and wR = 0.1167 for 3189 observed reflections （I〉 2σ（I）. Its formation mechanism was proposed.     

The reaction of perhalofluoroalkanes with sodium hydrogen sulfite or sodium dithionite in the presence of triethylamine

Hydrodehalogenation or hydrosulfonate-dehalogenation products, hydrohalofluoro-carbons or 2-hydropolyhalofluoroalkanesulfonates, were formed respectively from the title reaction under mild condition in good yield.     

Synthesis of Sug1-4GalNAcα disaccharides and their interaction with human blood antibodies

Disaccharides Sug1-4GalNAcα-Osp (Sug = Gal, Glc, GalNAc, GlcNAc in α- or β-configuration) were synthesized as spacer (sp) glycosides. Their strong interaction with serum antibodies of healthy donors was demonstrated using a printed glycan array (PGA).     

Synthesis and dyeing properties of some new monoazo disperse dyes derived from 2-amino-4-(2′,4′-dichlorophenyl)-1,3 thiazole

Ten new monoazo disperse dyes (4a–j) have been synthesized by coupling of diazotized 2-amino-4-(2′,4′-dichlorophenyl)-1,3 thiazole (2) with various N-alkyl derivatives of substituted aniline (3a–j) and their dyeing performance on polyester fiber has been assessed. These dyes are characterized by elemental analysis, UV–vis spectra, IR and NMR spectroscopy. The absorption maxima (λ_max) were recorded in DMF and were found to be in the range of 530–600 nm. The dyed polyester fabric showed fair to very good light fastness and very good to excellent washing and rubbing fastness properties with superior depth and levelness.     

Synthesis ofβ-glycosides of n-acetylglucosamine in the presence of HgI2

The use of HgI₂ as catalyst in the synthesis oftrans-glycosides of N-acetylglucosamine is described. Using this catalyst, -glycosides of N-acetylglucosamine with aglycons of different structures and lyophilicities have been synthesized. The possibility of performing oligosaccharide synthesis has been demonstrated.     

Alkylation of 2,4-dimethylphenol with (+)-α- and (−)-β-pinenes in the presence of aluminum xylenolate

Alkylation of 2,4-dimethylphenol with (+)-α- and (?)-β-pinenes in the presence of aluminum 2,4-dimethylphenoxide generated in situ led to the formation of mixtures of products, from which optically active compounds were isolated. The structure of 2-bornyl-4,6-dimethylphenol was determined by X-ray analysis; its (+)- and (?)-enantiomers were assigned (1R,2R,4S) and (1S,2S,4R) configurations, respectively.     

Synthesis with organoboranes. 21. Synthesis of α- and gd-bamascone

Selective syntheses of α- and gd-damascone, using allylic organoboranes as the key intermediates, are described.     

Synthesis and mesomorphic properties of 2-(4′-alkoxybiphenyl-4-yl)-1H-benzimidazole derivatives

Three series of 2-(4′-alkoxybiphenyl-4-yl)-1H-benzimidazole derivatives (nM-x), which possessed 5-nitrobenzimidazole (nM-N series), benzimidazole (nM-H series) or 5-methylbenzimidazole (nM-M series) units at the end of the molecule, were synthesised and characterised by infrared, ¹H- and ¹³C-nuclear magnetic resonance spectra, electrospray ionisation-mass spectrometry and elemental analysis. Their phase transition behaviour was investigated by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. All the compounds exhibited enantiotropic smectic mesophases with wide temperature domains for a carbon number in the alkoxy chain from 6 to 16, where the mesophase ranges were 14–91°C and 17–99°C during heating and cooling processes for the nM-N compounds, 7–25°C and 8–49°C for the nM-H compounds and 48–81°C and 52–85°C for the nM-M compounds, respectively. The effect of the length of alkoxy chain on mesomorphic properties was discussed. The nM-N and nM-M exhibited a much wider mesophase range whether during heating or cooling process than the corresponding nM-H series, especially for the longer terminal chain (n > 8), which indicated that the substituent in the benzimidazole moiety was helpful in increasing the mesophase stability.     

Transport properties of electrodialysis membranes in the presence of Zn2+ complexes with Cl−

The aim of this paper is to investigate the properties of anion exchange electrodialysis membranes in contact with aqueous solutions containing zinc chloride complexes. Measurements of electric resistance, water content, quantity of sorbed electrolytes, self-diffusion and electrotransport ionic fluxes were performed as a function of the composition of the external solutions. The results were analysed in relation to the complex formation inside the solutions.     

Synthesis and properties of furan derivatives. 1. Synthesis of 3,5-disubstituted Δ2-isoxazolines containing furfuryl fragments

3,5-Disubstituted ²-isoxazolines containing furan fragments have been synthesized by 1,3-dipolar cycloaddition reactions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 449–452, April, 1991.     

Synthesis and ozonization of (+)-4α-(1-trimethylsilyloxyethen-1-yl)-2-carene

(+)-4-(1-Trimethylsilyloxyethen-1-yl)-2-carene was synthesized, and the products of its ozonization were identified.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1984–1987, October, 1995.     

Synthesis of enantiopure β-azidoalcohols from their ketoazides by reduction with NaBH4 in the presence of alumina and in situ lipase resolution

An enantioselective synthesis of chiral β-azidoalcohols via the reduction of the corresponding ketoazides with NaBH₄ in the presence of moist aluminium oxide followed by an in situ lipase-mediated resolution is described. The efficiency of various lipases and the effect of solvents have also been studied for this method. The excellent results obtained under mild reaction conditions, indicates its applicability and importance over classical methods previously reported.     

Al4(2-); the anion-π interactions and aromaticity in the presence of counter ions

The influence of presence of counter ions and π-complexation with benzene on the bonding and magnetic properties of Al(4)(2-), the most studied all-metal cluster, is studied here. It is shown that complexation by either counter ions or benzene decreases the delocalization index between Al atoms and the magnitude of bond magnetizability, that is a Quantum Theory of Atoms in Molecules, QTAIM, -based magnetic index of aromaticity. Benzene forms two types of π-complexes with the Al(4) framework; CH-π (T-shaped) complexes and parallel π-π stacking (PPS) complexes. It is shown that variation in the π-charge of the Al(4) framework affects the relative stability of the T-shaped/PPS complexes. Free Al(4)(2-) forms a stable T-shaped anion-π complex with benzene but in the presence of cations, formation of PPS complexes is more favourable, energetically. It is suggested that this property could be used for designing molecular switches and tuneable anion sensors.     

The structure and pharmacological properties of the 4-acetoxy-1-(2-ethoxyethyl)-4-phenylpiperidine inclusion complex with β-cyclodextrin

Inclusion complex of 4-acetoxy-1-(2-ethoxyethyl)-4-phenylpiperidine with β-cyclodextrin was synthesized. Composition (1:2) and the structure of the complex were confirmed by NMR spectroscopy and thermal analysis. The results of pharmacological studies showed that the compound is of interest for in-depth testing, because of its deeper and more prolonged conduction anaesthesia, terminal (superficial) and infiltration anaesthesia along with less acute toxicity compared to the reference preparations.     

Synthesis of the 3-0, 4-0 and 6-0 Sulfates of Methyl 2-amino-2-deoxy-α-D-Glucopyranoside

Abstract

Starting with methyl 2-(benzyloxycarbonyl)amino-2-deoxy-α-D-glucopyranoside (1), the isomeric methyl 2-amino-2-deoxy-α-D-glucopyranoside 3-, 4-, and 6-sulfates have each been prepared by sulfation of suitably blocked intermediates. Tritylation and acetylation of 1 followed by detritylation gave methyl 3,4-di-0-acetyl-2-(benzyloxycarbonyl)amino-2-deoxy-α-D-glucopyranoside (3), having a free 6-hydroxyl group. Base catalyzed 0–4→0–6 acetyl migration provided the corresponding 3,6 di-O-acetyl derivative (4) posessing a free 4-hydroxyl group. Preparation of methyl 4,6-0-benzylidene-2-(benzyloxycarbonyl)amino-2-deoxy-α-D-glucopyranoside (9) provided the intermediate bearing a free 3-hydroxyl group. 0-sulfation of 3, 4, and 9 was effected with the pyridine sulfur trioxide complex in dry pyridine.     

Triazolyl C-nucleosides via the intermediacy of β-1′-ethynyl-2′-deoxyribose derived from a Nicholas reaction: Synthesis,photophysical properties and interaction with BSA

We report the design and synthesis of triazolyl donor/acceptor unnatural C-nucleosides via alkyne (sugar)—azide (aromatic) 1, 3-dipolar cyclo-addition reaction as a key step and studies on their photophysical properties. We have chosen β-1′-ethynyl-2′-deoxyribose as a precursor to synthesize triazolyl-C-nucleosides. Overcoming the difficulties, we obtain β-1′-ethynyl-2′-deoxyribose as a major product following a Co₂(CO)₈ catalyzed intramolecular Nicholas reaction. The 1,3-diaxial interaction is the driving force for the α to β-anomeric conversion while performing cobalt complexation followed by oxidation to afford β-1′- ethynyl-2′-deoxyribose as the major product. A Cu(I)-catalyzed click reaction between different aromatic donor/acceptor azides and β-1′- ethynyl-2′-deoxyribose generates the desired unnatural triazolyl donor-acceptor aromatic C-nucleosides (^cTB_Do/Ac) within 30 min. Single crystal X-ray structure shows the puckered conformation of sugar as C3′-exo. Studies on the photophysical properties suggests good fluorophoric as well as solvatochromic characteristics of these nucleosides. Two of the synthesised nucleosides, ^cTAnthB_Do and ^cTPyB_Do, are found to interact with BSA as the only tested protein with quenching of fluorescence signal. The designed bases, thus, might find applications in stabilizing a DNA and in the biophysical study thereof, if a pair of such donor acceptor C-nucleosides could be incorporated into a DNA sequence.