Advanced Materials Research Vols. 1033-1034

Abstract: An effective and sensitive method to determinate four parabens was developed by using graphene oxide (GO)-reinforced hollow fiber (HF) solid-phase microextraction combined with HPLC-PDA. Scanning electron microscope characterizations indicated that graphene oxide was successfully synthesized and modified in the pores of HF by ultrasonication. The conditions including extraction time, desorption time were optimized. The liner ranges of parabens were 0.01-5.00 μg/mL via the proposed management with a limitation of detection of 0.005 μg/mL. The extraction procedure based on GO-HF was successfully used for the determination of parabens in beer.

Abstract: A novel method for the spectrophotometric determination of isoniazid by silicomoly- bdenum blue has been established.The various effect factors on the spectrophotometric determination of isoniazid by silicomolybdenum blue were investigated in detail.The results showed that under certain reaction conditions,silicomolybdenum yellow could be reduced to silicomolybdenum blue by isoniazid, and the content of isoniazid was determinated indirectly through determinating the absorbance of the silicomolybdenum blue. The maximum absorption wavelength of chromogenic system is 740 nm, good linear relationship is obtained between the absorbance and the concentration of isoniazid in the range of 1.968～27.55 μg/mL,and the equation of the linear regression is A=0.0247+61.824ρ (μg/mL) with a linear correlation coefficient is 0.9995.This proposed method has been successfully applied to determinate of isoniazid in isoniazid tablets, and the results agree well with those obtained by pharmacopoeial method.

Abstract: The key intermediate, 6-bromo-2, 3-dihydroxybenzaldehyde, of salvianolic acid A (1) was reported, which was synthesized from commercially available 2-hydroxy-3-methoxybenzaldehyde.

Abstract: Tert-butyl (4R)-4-(methoxymethylcarbamoyl)-2,2-dimethylthiazolidine-3-carboxylate, an key intermediate of the natural product Biotin which is a water-soluble vitamin, involved in an essential part of the metabolic cycle causing catalytic fixation of carbon dioxide in the biosynthesis of fatty acids, sugars, and α-amino acids, was synthesized from L-cystine in overall yield 54% through three steps. The study including acetonization, Boc protection, N-methoxy-N-methyl amidation.

Abstract: A method was proposed for the determination of copper, iron, nickel, lead, cadmium and chromium in electroplating wastewater by ICP-AES. Working conditions and selection of spectral lines were optimized. The mixed and single standard for 6 elements were analyzed, spectrum with high sensitivity, low spectral interference, high ratio of signal with background, low detection limit were selected. The detection limit was 0.002, 0.003, 0002, 0.008, 0.002, 0.007mg/L. The effects of inhalation rate and the spectral intensity in nitric acid, hydrochloric acid, perchloric acid and sulfuric acid solution were tested. Nitrate acid with low viscosity, low surface tension and high atomization efficiency was selected. The accuracy and precision were tested, the relative error was less than 5.2%, relative standard deviation was less than 2.4%.It was accord with national standard. It proved that the determination of copper, iron, nickel, lead, cadmium and chromium in electroplating wastewater by ICP-AES was feasible.

Abstract: (5R, 7R)-methyl3, 5-dihydroxy-7-((4-methoxybenzyl) oxy) octanoate (2), as a key intermediate for the total synthesis of tarchonanthuslactone, was reported, which started from (R)-3-((4-methoxybenzyl) oxy) butanal (3) through few steps.

Abstract: A concise route to total synthesis of (+) - (6S, 2'R)-cryptocaryalactone (1) was designed and the key intermediate (7) was synthesized. The route included an Evans Aldol reaction, TBS protection and DIBAL-H reduction.

Abstract: A practical and diastereoselective synthetic study towards the cytotoxic and antimalarial compounds aculeatin A and B is described, which started from commercially available 1-tetradecanol and proceeded through a key Evans aldol reaction.

Abstract: Synthesis of (3, 4-bis ((tert-butyldimethylsilyl) oxy)-benzylidene) triphenyl- phosphorane, an important intermediate of salvianolic acid A (1), was reported, which synthetic route including protection, bromation and Wittig salt formation.

Abstract: A concise route to total synthesis of (+)-(6S, 2'R)-cryptocaryalactone (1) was designed and the key intermediate (3) was synthesized via an Evans Aldol reaction to construct the chiral hydroxyl group.