A Novel Approach for the Synthesis of C-Nucleoside Analogs by Constructing Benzoxazine Rings Linked to a Carbohydrate Moiety

Abstract

Dehydrative cyclization of the condensation product of 2, 3, 4, 5-tetra-O-acetyl-galactaryl chloride with anthranilic acid gave 1, 2, 3, 4-tetra-O-acetyl-1, 4-bis(4H-benzoxazin-4-one-2-yl)-galacto-tetritol. Its reaction with aniline in the presence of phosphorus trichloride afforded 1, 4-bis (3-phenylquinazolin-4-one-2-yl)-1, 2, 3, 4-tetra-O-acetyl-galacto-tetritol.     

Synthesis and Rearrangement of Mono and Bis-(p-Fluorophenyl)Hydrazones of Dehydro-L-Ascorbic Acid

Abstract

The mono- and bis-(p-fluorophenyl)hydrazones of dehydro-L-ascorbic acid were prepared. Oxidation of the bis(hydrazone) afforded 3,6-anhydro-3-C-(p-fluorophenylazo) L-xylo-2-hexul osono-1,4-1 actone-2-(p-fluorophenyl)hydrazone. Rearrangement of the bis(hydrazone) gave T-(p-fluorophenyl)-3-(L-threo-glycerol-1-yl)-pyrazoli n-4,5-di one-4-(p-fluorophenyl)hydrazone, whose periodate oxidation gave 3-formyl-1-(p-fluorophenyl pyrazol in-4.5-dione-3-4-(p-fluorophenyl)hydrazone that upon reduction gave 1-(p-fluorophenyl)-3-hydroxymethyl pyrazol in-4,5-dione-4-(p-fluorophenyl)hydrazone. The compounds were characterized as their acetates and benzoates.     

New furochromone derivatives as promising in-vitro anti-proliferative agents toward HepG-2 and MCF-7 cell lines with molecular docking studies

Based on the considerable features of the multicomponent reactions (MCRs) in the field of organic and medicinal chemistry, the present work was designed to synthesize a new series of imidazole, pyridine, and pyrimidine derivatives using MCRs to obtain new anti-proliferative agent beside exploration of their interaction mechanism by molecular docking technique. MCRs of furochromone carbaldehyde 1 , benzoin, and ammonium acetate afforded the corresponding 2,4,5-trisubstituted imidazole 2 . However, MCRs of 1 with benzoin, amine derivatives, and ammonium acetate yielded the corresponding 1,2,4,5-tetrasubstituted imidazole 3a,b . In addition, pyridine 4a,b-5a,b and pyrimidine derivatives 6a,d were synthesized via condensation of 1 with different carbonyl compounds and ammonium acetate or benzyl urea, respectively. The in-vitro anti-Proliferative activities of the new furochromone derivatives were screened toward MCF-7 and HepG-2 cancer cell lines as well as the normal cell line (human normal melanocyte, HFB4) in comparison to the known anticancer drugs: 5-fluorouracil and doxorubicin using MTT assay. Compounds 5a and 5b revealed effective anti-proliferative activity against MCF-7 cell lines with IC ₅₀ 18 and 22 μg/mL, respectively, compared to 5-fluorouracil (IC ₅₀ of 13 μg/mL). However, compounds 6a-d exhibited potent activity against HepG-2 cancer cell lines of IC ₅₀ ranging from 18 to 20 μg/mL compared to doxorubicin (IC ₅₀ of 14 μg/mL). Moreover, the binding mode of the most active furochromones 5a,b and 6a-d inside the active site of the epidermal growth factor receptor (EGFR) kinase enzyme (PDB ID: 5CAV) were studied using molecular docking technique. Compounds 6b,c showed excellent docking results compared to the known EGFR inhibitors ( 4ZQ ).     

Removal of Pb and Cd from aqueous media and fish liver using novel polyurethane foam functionalized with pyrazolone as a new metal ion collector

In the present paper, an off-line preconcentration procedure for the determination of cadmium and lead by flame atomic absorption spectrometry (FAAS) is proposed. Polyurethane foam (PUF) functionalized with o-aminophenol (o-AP) followed by Pyrazolone (Pyr) packed in a minicolumn was used as a sorbent material. The metals were retained on the modified PUF, from which it could be eluted and effectively preconcentrated. The detection limits were 0.072 and 0.016 μg L⁻¹ for Pb and Cd respectively. Enrichment factors were 250 and 319 for lead and cadmium respectively. The procedure has been applied successfully to metal determination in water samples, fish liver and reference material.      

Square-wave adsorptive stripping voltammetry at glassy carbon electrode for selective determination of manganese. Application to some industrial samples

A new method to determine manganese by voltammetry after controlled adsorptive accumulation of the manganese–ammonium–acetate at the glassy carbon electrode is described. The manganese complex gives well-defined voltammetric peak at pH 4.0 and 9.0. Cathodic stripping voltammetry combined with the Osteryoung square-wave mode at the glassy carbon electrode gave rise to both sensitivity and selectivity of the determination of manganese in some industrial samples. The method offers enhanced sensitivity in comparison to analogous measurements presented in the literature. The detection limit with 5 min accumulation is 0.022 μg l⁻¹ . Simultaneous determination of manganese in presence of Cu(II), Pb(II) and Zn(II) could be easily done using anodic stripping voltammetry at pH 4.0. Calibration plots are constructed and the method was checked with the aid of standard industrial reference samples giving values of standard deviations between 1.2 and 1.8.     

Synthesis and characterization of tin(IV) antimonate and study of its ion-exchange equilibria

Tin(IV) antimonate with different Sb/Sn molar ratios has been prepared. The characterization of the product materials was carried out using X-ray diffraction pattern, themal analysis and infrared spectra. The saturation capacities of sodium and cesium were found to increase with Sb/Sn molar ratios. TheK _d values on thermal treatment of tin(IV) antimonate, as a cation exchanger, have been measured for some heavy metal ions in the temperature range of 50–400 °C. The maximum adsorption of 10^–4M of the metal ions studied was obtained at 400 °C. The selectivity sequence was Eu³⁺>Co²⁺>Sr²⁺>Cs⁺ for the sample heated up to 400 °C. No adsorption was observed on the sample heated at 700 °C because of the formation of SnO₂ and Sb₆O₁₃.     

Simultaneous micellar electrokinetic chromatography and liquid chromatography of adriblastina and tarabine PFS Their application to some biological fluids

The current work presents analytical procedures for simultaneous determination of tarabine PFS and adriblastina by micellar electrokinetic chromatography (MEKC) and liquid chromatography (LC). For MEKC analysis, separations and identifications were accomplished using uncoated fused-silica capillary with hydrodynamic injections in the presence of 50mM borate/phophate pH 8.7 and 100mM SDS. The migration times of tarabine PFS and adriblastina were found to be 2.70 and 6.40min, respectively. Calibration curves were established for 10-300ng/mL (r=0.998) tarabine PFS and for 8-120microg/mL (r=0.999) adriblastina. For LC analysis, separations were performed on teicoplanin stationary phase with reversed mobile phase containing methanol:buffer pH 4.05 (20:80%, v/v) at 285nm. The retention times of tarabine PFS and adriblastina were 5.18 and 7.20min, respectively. Calibration curves were established for 3-90microg/mL (r=0.998) tarabine PFS and for 10-120microg/mL (r=0.999) adriblastina. Both MEKC and LC methods were applied for the simultaneous determination of analytes in urine samples.     

Uses of 5-Methylresorcin-bonded polyurethan foam as a new solid phase extractor for the selective separation of mercury ions from natural water samples

In this work, 5-Methylresorcin (MR) bonded to untreated polyurethane foam (PUF) was successfully employed as a sorbent (MR-PUF) for the selective separation and determination of mercury in natural water samples. Mercury can be quantitatively recovered in the pH range of 5-7. The system presented a minicolumn packed with the new sorbent, where the sample solution was passed through it for a period of time and an eluent solution stripped out the retained mercury, which was further determined with dithizone. The new matrix was characterized by using different tools (IR spectra, stability and density). The kinetics of mercury uptake by the new matrix was found to be fast, reaching equilibrium in 20 minutes. A preconcentration factor of 350 was achieved. The proposed preconcentration procedure was applied successfully to the selective separation and determination of trace mercury in natural water samples.