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61.
Nani Babu PalakurthyBhubaneswar Mandal 《Tetrahedron letters》2011,52(52):7132-7134
The N-hydroxybenzotriazole (HOBt) sulfonate esters undergo amidation under ambient conditions in the presence of di-isopropylethyl amine. This method can be applied to varieties of amines including sterically hindered amino acid esters in less time with reasonably good yields.HOBt ester of sulfonic acids can be a replacement for pentafluorophenyl and trichlorophenyl ester as well as chloride moiety of sulfonyl chloride for amidation. 相似文献
62.
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. 相似文献
63.
Bromination of alkynes using sodium bromide in the presence of sodium perborate provides a convenient and safe method for generating vicinal dibromoalkenes. 相似文献
64.
Mohamed S. A. El‐Gaby Jehane A. Micky Nadia M. Taha Marwa A. M. Sh. El‐Sharief 《中国化学会会志》2002,49(3):407-414
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. 相似文献
65.
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. 相似文献
66.
Göbel Aa Thomsen A McArdell CS Alder AC Giger W Theiss N Löffler D Ternes TA 《Journal of chromatography. A》2005,1085(2):179-189
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. 相似文献
67.
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. 相似文献
68.
69.
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. 相似文献
70.
Sachin B. Baravkar Mahendra A. Wagh Debasish Paul Manas Santra Gangadhar J. Sanjayan 《Tetrahedron letters》2018,59(38):3473-3476
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. 相似文献