Investigation of Breaking Efficiency of N-Glycosidic Bond Between Sulfonamide and Honey

Sulfonamide residue in honey existed in a form bonded to sugar via the N-glycosidic bond.It would result in the possible underestimation of concentration of sulfonamide if it is not decomposed by chemi...     

Simple and sensitive monitoring of sulfonamide veterinary residues in milk by stir bar sorptive extraction based on monolithic material and high performance liquid chromatography analysis

A simple, rapid, and sensitive method for the quantitative monitoring of five sulfonamide antibacterial residues (SAs) in milk was developed by stir bar sorptive extraction (SBSE) coupling to high performance liquid chromatography with diode array detection. The analytes were concentrated by SBSE based on poly (vinylimidazole–divinylbenzene) monolithic material as coating. The extraction procedure was very simple, milk was diluted with water then directly sorptive extraction without elimination of fats and protein in samples was required. To achieve optimum extraction performance for SAs, several parameters, including extraction and desorption time, desorption solvent, ionic strength and pH value of sample matrix were investigated. Under the optimized experimental conditions, low detection limits (S/N = 3) quantification limits (S/N = 10) of the proposed method for the target compounds were achieved within the range of 1.30–7.90 ng/mL and 4.29–26.3 ng/mL from spiked milk, respectively. Good linearities were obtained for SAs with the correlation coefficients (R²) above 0.996. Finally, the proposed method was successfully applied to the determination of SAs compounds in different milk samples and satisfied recoveries of spiked target compounds in real samples were obtained.     

A new sulfonamide derivative as magnesium ion receptor: N-tosyl-2,6-diisopropyl-4-(2,3-dimethoxylbenzoylamide)aniline

N-Tosyl-2,6-diisopropyl-4-(2,3-dimethoxylbenzoylamide)aniline (1) has been synthesized and its metal ion (Na⁺, K⁺, Ca²⁺, Mg²⁺) coordinating properties investigated by FT-IR, ESI-MS, and ¹H NMR methods. Among the tested metal ions, the overall stability constant (log K) for Mg²⁺ (6.89) is the highest (Na⁺, 5.64; K⁺, 5.43; Ca²⁺, 5.51) in 10% water/THF at 25.0 ± 0.5 °C determined by UV-vis spectroscopy, indicating that 1 is a potent ionophore for Mg²⁺ ion.     

Synthesis and anticancer activity of conformationally constrained Smac mimetics containing pseudo β turns

Herein, we report synthesis and in vitro anticancer activity of conformationally constrained Smac mimetics containing reverse turn inducing motifs “Ant-Pro” and “^sAnt-Pro”. The synthesis of Smac analogs with diverse hydrophobic groups at the C-terminus was carried out using solution phase peptide synthesis. The synthesis of Ant-Pro containing analogs 3a–j was carried out by ring opening of benzoxazinones 7a–c, whereas, their sulfonamide counterparts 4a–h were synthesized by using routine acid-amine coupling reaction. In vitro anticancer studies against breast cancer cell line MDA-MB-231 revealed that some of the new analogs had better anticancer activity than the standard AVPI Smac tetrapeptide.     

PTAB mediated open air synthesis of sulfonamides,thiosulfonates and symmetrical disulfanes

A facile methodology has been described which has successfully simplified the generation of sulfonamides, thiosulfonates and symmetric disulfanes. This “trio” of reactions occur in an open air metal free atmosphere and has also been scaled up to grams making it suitable for commercialization. The reactions also have been successfully carried out with asymmetric variants, thus contributing to the chiral pool. The user friendly “trio” enables easy generation of these versatile sulfur analogues and the reaction condition employed depict an economic outline.     

Antimicrobial Activity of Some Novel Thiourea,Hydrazine, Fused Pyrimidine and 2‐(4‐Substituted)anilinobenzoazole Derivatives Containing Sulfonamido Moieties

Thiophosgenation of sulfonamides 1a‐c in the presence of dilute HCl at room temperature furnished the isothiocyanatosulfonamides 2a‐c and treatment with aromatic amines gave 1,3‐disubstituted thioureas 3a,b . Also, interaction of two molecules of 2c with 1,4‐phenylenediamine yielded the novel bisthiourea 4 . Cyclocondensation of 2 with ortho amino carboxylic acid compounds such as anthranilic acids 8 , 5‐amino‐1‐phenyl‐pyrazol‐4‐carboxylic acid 9 and 4,5,6,7‐tetrahydro‐2‐amino‐benzo[b]thiophene‐3‐carboxylic acid 10 furnished the fused thiopyrimidines 11a‐d, 12 and 13 , respectively. 2‐Anilinobenzoazole derivatives 15a‐c, 16a, b and 17a,b were obtained through cyclocondensation of 2 with 1,2‐dinucleophiles.     

Quantitative determination of sulfonamide in meat by liquid chromatography-electrospray-mass spectrometry

This paper describes a newly developed liquid chromatography–electrospray-mass spectrometry (LC–ES-MS) method for the quantitative determination of nine commonly used sulfonamides (sulfadiazine, sulfapyridine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfisoxazole, sulfadimethoxine, sulfaquinoaline and sulfaphenazole) in meat. [M+H]⁺ and [M+Na]⁺ were the two major ions detected in positive ion mode. Selective ion monitoring was employed for quantitative determination. Satisfactory linearity, 0.1–10 μg ml⁻¹, of each compound was obtained. Blank meat samples were fortified at levels between 50 and 500 μg kg⁻¹. [Phenyl-¹³C6]sulfamethazine was used as internal standard. Sulfonamides were isolated from meat with a solvent extraction procedure and then determined by LC–ES-MS. The limits of detection were below 10 μg kg⁻¹. The application of this newly developed method was demonstrated by analyzing various beef, pork and chicken samples from local markets.     

Extraction and determination of sulfonamides, macrolides, and trimethoprim in sewage sludge

Pressurized liquid extraction (PLE) was optimized and validated for the determination of sulfonamide and macrolide antimicrobials and trimethoprim in sewage sludge samples. A mixture of water/methanol (50:50, v/v) was found as the most efficient extraction solvent. A temperature of 100 degrees C and a pressure of 100 bar were chosen for extraction. Two cycles of 5 min each efficiently extracted at least 97% of the total extractable amount of all studied analytes from activated sludge. The limits of quantification (S/N= 10) varied between 3 and 41 microg/kg dry weight (dw) and the relative recoveries ranged between 78 and 142%. Additionally, the influence of pH and different LC/MS/MS systems on the absolute recoveries was assessed. Of the investigated antimicrobials sulfapyridin, sulfamethoxazole, trimethoprim, azithromycin, clarithromycin and roxithromycin were detected in municipal sewage sludge samples. Concentrations in activated sludge ranged up to 197 microg/kgdw. In comparison, results obtained by ultrasonic solvent extraction were significantly lower for sulfonamides and in tendency lower for macrolides.     

Approaches to the rational design of molecularly imprinted polymers

In our experience the efficient design of molecularly imprinted polymer (MIPs) for novel templates has proved difficult. Following commonly used imprinting protocols, MIPs designed against one template show both a lack of capacity and poor specificity for rebinding either the template or structurally similar analytes. Optimisation methods that involve changing one factor at a time can be laborious.A novel approach for the optimisation of MIPs using chemometrics is described. Sulfonamides, common drug residues in foodstuffs, were used as the model analytes with a methacrylic acid/ethylene glycol dimethacrylate MIP. To avoid the inaccuracies in measurement caused by template bleed a multi-analyte competition rebind assay was developed to select suitable sulfonamides to be used as the template for the MIP, and for the rebind analyte in the chemometric optimisation study. The rebinding efficiencies were monitored by HPLC. The template sulfonamide was selected as sulfamethazine (SMZ), and the rebind analyte as sulfadimethoxine (SDIM). The template:monomer:cross-linker (T:M:X) ratio of the SMZ block MIP was then optimised using a three-level full factorial design to predict a MIP with the highest rebind capacity. On synthesis this was 38.8% for SDIM in a solid phase extraction (SPE) application agreeing with the predication. The factorial design was further utilised to predict an optimum T:M:X ratio for the production of a class specific MIP, capable of binding a range of sulfonamides simultaneously. The predicted optimum T:M:X ratios of (1:10:55) and (1:10:10) were found to be different to commonly used ratios from the MIP literature.     

The synthesis and recognition properties of colorimetric fluoride receptors bearing sulfonamide

Two artificial receptors, 1,2-bis-p-substituted phenyl-sulfonamido-4,5-bis-nitrobenzene, have been designed and synthesized. The interactions of these receptors with halide anions are determined by UV-vis and ¹H NMR titration experiments. Results indicate that two receptors have strong sensitivity and selectivity for fluoride among halide anions. In addition, the visible color changes upon the addition of fluoride anion can make the receptors as convenient detection tools for fluoride anion.