Kadir Ay

Synthesis and antimicrobial activities of two novel amino sugars derived from chloraloses

The synthesis of 5-amino-5-deoxy-1,2-O-(S)-trichloroethylidene-beta-L-arabinofuranose and 6-amino-6-deoxy-1,2-O-(S)-trichloroethylidene-alpha-D-glucofuranose is described by a simple three- or four-step route. Antibacterial potency of the new compounds was determined using an inhibition zone diameter test. The results show that these compounds have a broad-spectrum activity against Gram-positive, Gram-negative bacteria and Candida albicans.

Acid promoted intramolecular formation of 3,5-anhydro-1,4-furano-7-ulose derivatives via the Wittig-cyclization procedure and their antimicrobial properties

We report a convenient method for the synthesis of 3,5-anhydrofuranose derivatives. Formation of the 3,5-anhydro (oxetane) rings was achieved by the Wittig-cyclization procedure under acid promoted conditions starting from 5(E)-eno-1,4-furano-7-ulose derivatives (1, 4, and 7). Unprotected hydroxyl groups on C-3 of the furanose rings added intramolecularly to the acyclic double bond under very mild acidic conditions in methanol to form the stereoisomeric 3,5-anhydro derivatives in good yields. The products (2, 3, 5, 6, and 8) were found to exhibit antibacterial properties. The reaction was found to be strongly solvent dependent as use of methanol instead of chloroform afforded 5-acetylmethyl-furfural 9 as a major product instead of the expected oxetane. All of the synthesized compounds were tested for antimicrobial activity against Staphylococcus aureus ATCC6538-P, Bacillus subtilis ATCC 6633, Salmonella typhimurium CCM 5445, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 12228, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae CCM 2318, and Candida albicans ATCC 10239 and exhibited a range of activities against selected microorganisms.

The Knoevenagel-Doebner Reaction on 1,2-O-(2,2,2- Trichloroethylidene) Derivatives of D-Gluco- and D-Manno- furanose †

The synthesis of new α,β-unsaturated furanuronic acid derivatives of α-gluco- (3), β-gluco- (6) and β-manno-chloraloses (9) via a convenient one pot procedure using the Knoevenagel-Doebner reaction approach are described. The dialdofuranose derivatives were reacted with malonic acid under Knoevenagel-Doebner reaction conditions and (E)-α,β-unsaturated furanuronic acid derivatives were obtained.

Synthesis and antimicrobial evaluation of sulfanilamide- and carbohydrate-derived 1,4-disubstitued-1,2,3-triazoles via click chemistry

Abstract4-Sulfanilamido substitued-1,2,3-triazoles conjugated with monosaccharides (8–17) including d-glucose, d-galactose, d-mannose, and d-fructose were synthesized in good yields from azidosugars with propargyl sulfanilamides using copper catalyst 1,3-dipolar cycloaddition reaction (CuAAC). The structures of new compounds were elucidated by liquid chromatography-mass spectrometry, infrared, one-dimensional- and two-dimensional-nuclear magnetic resonance techniques. All of the new compounds were tested in vitro against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans for their antibacterial and antifungal activities. Experimental results showed antimicrobial activity with minimum inhibitory concentrations values a ranging from 0.078 to 5.0 mg/mL against test microorganisms.

Determination of Some Chemical Parameters and Antimicrobial Activity of Traditional Food: Mesir Paste

The antimicrobial activities and some chemical properties of the traditional Turkish food called mesir paste were studied. Results of chemical analysis for moisture and volatiles, water-insoluble components, refractive index, soluble solids content, raw fiber, invert sugar, total ash, 5-hydroxymethylfurfural, acidity, and pH were calculated as 17.06%, 2.55%, 1.491, 80.2%, 0.70%, 40.54%, 0.13%, 44 mg/kg, 0.9% anhydrous citric acid, and 3.6, respectively. Mesir paste was extracted individually by six solvents with different polarity, and antimicrobial activities of each extracts were determined against 12 microbial strains, mostly food-borne, including pathogens, by the agar well diffusion method. All extracts obtained showed antimicrobial activity ranging from 8 mm to 40 mm, and the butanolic extract displayed stronger antimicrobial activity against all tested microorganisms; Gram-positive strains were found to be more sensitive than Gram-negative strains. Antimicrobial potency of n-butanol extracts of mesir paste was determined in term of minimal inhibitory concentration and minimal bactericidal concentration for the sensitive microorganisms. In addition, some commercial antibiotics such as ampicillin, gentamicin, and nystatin were used as positive controls to determine the sensitivity of the strains.

Syntheses of 1,2,3-triazole-bridged pyranose sugars with purine and pyrimidine nucleobases and evaluation of their anticancer potential

ABSTRACT With the aim to create a library of compounds with potential bioactivities by combining special characteristics of two important groups such as nucleobases and carbohydrates, twenty 1,4-disubstituted-triazole nucleosides were synthesized in good yields (80-94%) using the copper catalyzed ‘Click’ reaction between azido-modified pento- or hexopyranoses and alkyne-bearing pyrimidine or purine nucleobases. Structural elucidation was made with the assistance of spectroscopic techniques such as FTIR, 1D-, 2D-NMR, and ESI-TOFMS. All the synthesized triazole nucleosides were evaluated for their cytotoxic activity against three human cancer cell lines (MDA-MB-231, Hep3B, PC-3) by using the MTT assay. Particularly, compounds 3a and 1b were identified as potential hits against Hep3B cell.

Synthesis, characterization and non-isothermal decomposition kinetic of a new galactochloralose based polymer.

A glycopolymer, poly(3-O-methacroyl-5,6-O-isopropylidene-1,2-O-(S)-trichloroethylidene-α-d-galactofuranose) (PMIPTEG) was synthesized from the sugar-carrying methacrylate monomer, 3-O-methacroyl-5,6-O-isopropylidene-1,2-O-(S)-trichloroethylidene-α-d-galactofuranose (MIPTEG) via conventional free radical polymerization with AIBN in 1,4-dioxane. The structures of glycomonomer and their polymers were confirmed by UV-vis, FT-IR, (1)H NMR, (13)C NMR, GPC, TG/DTG-DTA, DSC, and SEM techniques. SEM images showed that PMIPTEG had a straight-chain length structure. On the other hand, the thermal decomposition kinetics of polymer were investigated by means of thermogravimetric analysis in dynamic nitrogen atmosphere at different heating rates. The apparent activation energies for thermal decomposition of the PMIPTEG were calculated using the Kissinger, Kim-Park, Tang, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Friedman methods and were found to be 100.15, 104.40, 102.0, 102.2, 103.2 and 99.6 kJ/mol, respectively. The most likely process mechanism related to the thermal decomposition stage of PMIPTEG was determined to be a Dn deceleration type in terms of master plots results.

The Newest Member of the Family of Chloralose: Synthesis of -Ribochloralose and Some Derivatives

3, 77%) was obtained from the reaction of1 with potassium t-butoxide. This novel orthoester is expected to be useful as a glycosyl donor in the formations of new ribofuranoside units. 3O-Methyl-ribochloralose ( 5 )w as synthesized in 75% yield via the methylation of 1 .5 -O-Tosyl-ribochloralose (6, 61%) was prepared with monotosylation reaction of 1 .T reatment of6 with NaN3 in DMF gives a 5-azido-5-deoxy-ribochloralose ( 7) in 77% yield. The azidosugar ( 7 )w as reduced to 5-amino-5-deoxy-ribochloralose ( , 72%) with triphenylphosphine according to Staudinger’s reduction procedure.

Formulation, characterization, cytotoxicity and Salmonella/microsome mutagenicity (Ames) studies of a novel 5-fluorouracil derivative

5-Fluorouracil is one of the first line drugs for the systemic therapy of solid tumors like breast, colorectal, oesophageal, stomach, pancreatic, head and neck. It could be shown that sugars can improve the absorption across cell membranes and can help to bypass some pharmacokinetic problems. Carbohydrates as most common organic molecules are an important issue of plant and animal metabolisms. They are non toxic and have important duties in the body like participating in DNA and RNA synthesis and being responsible for energy production. In addition, they have many hydroxyl, aldehyde and ketone groups that attract attention for synthesis as a potential drug derivative. 1,2,3,-Triazole compounds have also important role in heterocyclic chemistry because of their pharmaceutical properties and their high reactivity, which could be used as a building block for complex chemical compounds. In this study, following the “Click Reaction” of 5-FU and tetra-O-acetylglycose the 5-fluorouracil derivative 1-[{1′-(2″,3″,4″,6″-tetra-O-acetyl-β-d-glycopyronosyl)-1′H-1′,2′,3′-triazole-4′-yl} methyl]5-fluorouracil was synthesized. Following, a micellar formulation of 5-Fluorouracil derivative was prepared and characterized in terms of particle size, polydispersity index, zeta potential, refractive index and pH. Furthermore, the cytotoxicity and mutagenicity of the 5-fluorouracil derivative was investigated using an in vitro cell culture model and the AMES test. According to the results of this study, the novel 5-fluorouracil derivative could be a drug candidate for the therapy of cancer and needs further in vivo investigations.

Synthesis of triazolylmethyl-linked nucleoside analogs via combination of azidofuranoses with propargylated nucleobases and study on their cytotoxicity

Copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition reactions (CuAAC) between azidofuranoses and propargyl-nucleobases were carried out in the presence of CuSO4·5H2O and sodium ascorbate as catalytic system to provide the corresponding 1,4-disubstituted-1,2,3-triazole-bridged nucleoside analogs in good yields. Twelve new sugar-based triazolylmethyl-linked nucleoside analogs were synthesized and screened for their cytotoxic activity against MDA-MB-231, Hep3B, PC-3, SH-SY5Y, and HCT-116 cancer cell lines and control cell line (L929). Most of the compounds were moderately effective against all the cancer cell lines assayed. Particularly, among the tested compounds, 1,2,3-triazole-linked 5-fluorouracil–mannofuranose hybrid was found to be the most potent cytotoxic agent against HCT-116, Hep3B, SH-SY5Y cells with IC50 values of 35.6, 71.1, and 75.6 μM, respectively. None of the triazolylmethyl-linked nucleoside analogs exhibited cytotoxic effect against the control cells L929.