An Improved Synthesis of Methyl 2-N-formylamino-2-(dimethoxyphosphinyl)-acetate

The title compound was synthesized in high yield by a one pot procedure. Besides allowing an easy purification, this procedure ensures high yields and ready scaling up.     

Convenient,multicomponent, one-pot synthesis of highly substituted pyridines under solvent-free conditions

Highly substituted pyridine derivatives have been accessed through an efficient, one-pot, multicomponent reaction of aldehydes, malononitrile, and ammonium acetate in the presence of triethylamine as a catalyst under solvent-free conditions. This procedure affords the desired products in high purity and has advantages such as short reaction time, excellent yields, and simple workup procedure. This procedure affords the desired products in moderate to high yields and has such advantages as short reaction time and simple workup procedure.     

Measurement of total protein in urine: Comparison of two dye-binding procedures with a gel filtration/modified biuret method

Two dye-binding methods for the determination of urinary total protein concentration have been compared to a biuret-based procedure requiring a preliminary gel filtration step. The biuret-based procedure is claimed to be both specific and sensitive for the measurement of protein in urine. With those urines having relatively low protein concentrations, the dye-binding methods provide values about one-half of those given by the modified biuret procedure. This difference disappears when urines containing high levels of protein are measured. The lower results obtained at normal protein levels are most likely caused by the inability of dye-binding methods to measure proteins of high carbohydrate content (such as uromucoid) accurately. In spite of this limitation, both dye-binding methods appear suitable for routine use. In contrast to the biuret-based procedure, we found the dye-binding methods to be free from interferences by compounds known to appear in urine in high concentrations.     

Rapid one-pot preparation of 2-substituted benzimidazoles from 2-nitroanilines using microwave conditions

A high yielding one-pot procedure for the generation of 2-substituted benzimidazoles directly from 2-nitroanilines by in situ reduction and cyclization using a microwave procedure is described.     

Solvent-free synthesis of dihydropyrimidinones catalyzed by alumina sulfuric acid at room temperature

A simple, efficient and practical procedure for the Biginelli reaction using alumina sulfuric acid (ASA) as a novel acid catalyst is described under solvent-free conditions. The catalyst exhibited remarkable reactivity at room temperature. The method offers several advantages including high yields, environmentally friendly procedure, short reaction times and simple work up procedure.     

Colorimetric determination of inorganic iodine in fortified culinary products

The presented colorimetric procedure only requires simple laboratory equipment and is suitable as a routine procedure for checking concentrations of iodine in fortified culinary products. The Moxon and Dixon colorimetric procedure for iodine determination has been optimised for the determination of iodide and iodate in fortified culinary products, always containing high salt levels. The high sensitivity of the method permits a high dilution of the product solutions, thus reducing interferences from the inherent colour of the products. The calibration is linear in the range from 0 to 12 microg L(-1) of iodine with R2 > 0.99. A series of commercial culinary products were used to validate the method. Recoveries of iodine, added as iodide and/or iodate, were generally in the range 100+/-10%. High concentrations of chloride are essential to obtain a complete recovery of iodate. Limit of quantification was estimated to be 2 mg kg(-1) of product, based on 2-3 g of product. Concentrations of iodine determined with this method were similar to those obtained by an ICP-MS procedure.     

Microwave single walled carbon nanotubes purification

A new single walled carbon nanotubes (SWCNTs) purification procedure has been developed; it consists in a combination of air treatment and acid microwave digestion leading to a high purity SWCNTs material; the procedure reaches high metal removal percentages and the operation time is drastically reduced compared to conventional acid reflux treatments.     

Automated balances of the second generation

In automatic weighing a Lorentz-force is commonly used to compensate for the force to be measured. In this procedure the compensating force is adjusted such that it brings back the balance beam to its equilibrium position whenever the force to be measured varies. To avoid instabilities of the feedback system, the high frequencies are usually blocked In the feedback system applying low pass filtering. This Involves loss of Information present in the high frequency part of the (compensating) force signal. On the basis of the equation of motion of the balance, an analysis is given which provides a correction procedure Improving the high frequency performance of automated balances.     

A Novel One-Pot Conversion of 2-Naphthols into 1,1′-Binaphthalene-2,2′-Diols

A simple two-step, one-pot procedure based on the treatment of sodium 2-naphthoxide with bromine yields 1,1′-binaphthalene-2,2′-diol in a high yield and an excellent purity. The procedure is applicable also to preparation of the symmetrically disubstituted analogues.     

Extraction of Proserine from Biological Tissues Using Unmodified Silicas

Sorption characteristics of proserine on unmodified silica with different pore sizes and specific surfaces were studied. A procedure was developed for the determination of proserine in biological materials (kidney and liver) by gas chromatography using unmodified silica. The procedure is characterized by rapidness, high sensitivity, and high precision.     

Rapid One‐Pot Preparation of 2‐Substituted Benzimidazoles from Esters using Microwave Conditions

A high‐yielding one‐pot procedure for the generation of 2‐substituted benzimidazoles first from esters using a microwave procedure is described.     

一种快速高效分解1,1-二乙酸酯的方法

研究了硅胶硫酸酯催化下1,1-二乙酸酯的分解反应. 该方法具有操作简单、反应时间短、收率高、无污染、催化剂可回收重复使用等特点.     

Recent developments in automated structure elucidation of natural products

Advancements in the field of Computer-Assisted Structure Elucidation (CASE) of Natural Products achieved in the past five years are discussed. This process starts with a dereplication procedure, supported by structure-spectrum databases. Both commercial and free products are available to support the procedure. A number of new programs,as well as advancements in existing ones, are presented. Finally, the option to validate the result by an independent procedure, a high quality ab initio quantum mechanical calculation, is discussed.     

Preparation of Monoalkyl Terephthalates: An Overview

Terephthalic acid can be readily converted to the corresponding monoalkyl terephthalate in high yield, via a two‐step procedure. This method is advantageously compared to the more representative methods described in the literature. The purification of the expected monoester, a crucial problem for this synthetic pathway, is discussed, and an original procedure has been developed.     

Synthesis of Substituted Diphenylamines Under Phase Transfer Catalysis

A convenient procedure for the synthesis of N-[(trifluoromethyl) nitrophenyl] substituted anilines by means of a chloro-substitution reaction under conditions of phase-transfer catalysis (PTC) is reported. The ipso-substitution product is obtained with high yield. This method provides a general procedure for the synthesis of diphenylamines bearing electron-withdrawing groups in both aromatic rings.     

纳米金-蛋白A介导抗体定向固定的压电传感及电化学特性研究

以纳米金为载体标记蛋白A(PA),用于介导抗体在压电石英晶体金电极表面的定向固定化.以补体C_1q抗体为模型,采用压电传感技术实时监察了此敏感界面的免疫反应过程,并考察了与补体C_1q免疫反应的压电响应性能.金标PA固定抗体的方法与传统的直接PA固定化方法相比较,具有传感界面无需活化,固定抗体的免疫活性高等优点,可对相应抗原进行高灵敏的压电免疫检测.分别利用循环伏安和电化学交流阻抗技术对金标PA固定抗体及其免疫反应的动力学过程进行了表征.     

A radiochemical neutron activation analysis method for the determination of tin,arsenic, copper and antimony for the forensic comparison of bullet lead specimens

Trace element characterization of bullet lead by instrumental neutron activation analysis (INAA) is hampered by the high spectral background due to antimony, normally present in high concentration in bullet lead. Tin is indicated to be a very useful element for characterization purposes. Beta-active¹²¹Sn is a suitable nuclide for quantitation of tin provided it is separated in high radiochemical purity. A radiochemical procedure capable of determining tin down to 10 ppm in bullet lead, a sequential procedure for its determination along with copper, arsenic and antimony and the application of this procedure for the determination of the contents of these elements in various bullet leads are described. This method has been applied to a “Rhinoceros shoot-out” case, referred to our laboratory.     

Contact area lithography and pattern transfer of self-assembled organic monolayers on SiO2/Si substrates

We describe a procedure for one-step patterning and transfer of self-assembled organic monolayers (SAMs) on SiO(2)/Si substrates. This procedure was inspired from an idea of pattern formation at contact area, which realizes high patterning fidelity, and enables a universal approach for the micro/nanometre scale patterning of SAMs.     

Efficient and sensitive method of DNA silver staining in polyacrylamide gels

DNA silver staining is widely used to detect DNA fragment in polyacrylamide gel with high sensitivity. Conventional procedures of the silver staining involve several steps, which take about 40 min to 2 h in total. To improve the efficiency of DNA silver staining, a more efficient protocol is developed in this study. The procedure comprises only four steps including impregnating, rinsing, developing, and stopping, and could be completed within 20 min. Nitric acid and ethanol in the silver-impregnation step of the new procedure eliminates the need for prior treatment of gels with a fixing solution and following rinse prior to impregnation with silver. The procedure has high sensitivity and long storage lifetime. The minimum detectable mass of DNA is 0.44 and 3.5 ng in denaturing and nondenaturing polyacrylamide gel, respectively.     

Ionic liquid mediated 1,3-dipolar cycloaddition of azomethine ylides: a facile and green synthesis of novel dispiro heterocycles

A greener, facile and efficient one-pot, three-component procedure for the synthesis of novel dispiropyrrolidine-bisoxindole derivatives by cycloaddition trapping of azomethine ylides generated in situ, via decarboxylative condensation of isatin with sarcosine (α-amino acid), has been reported in [bmim]PF₆, an ionic liquid as a recyclable solvent in excellent yield without using any catalyst. This protocol provides mild reaction conditions, high yields of product in short reaction time, high regio- and stereoselectivity, operational simplicity and environmentally benign procedure.