Common Reagents Research Articles

Direct Conversion of Aldehydes and Ketones into Azides by Sequential Nucleophilic Addition and Substitution

This report describes the direct conversion of aldehydes and ketones into alkyl azides by the addition of common organometallic reagents and tandem conversion of the resulting alkoxides without isolation of the intermediate alcohols. A wide range of aldehydes and organometallic reagents (R–Li or R–MgX) are suitable participants in this process. Additional reaction telescoping beyond azide formation is demonstrated.

A study on experimental characteristic of co-pyrolysis of municipal solid waste and paper mill sludge with additives

The thermal characteristics and kinetics of municipal solid waste (MSW) and paper mill sludge (PMS) and their blends were evaluated under pyrolysis condition with different additives, MgO and activated carbon (AC) which were the two common chemical reagents and different content (5% and 10%). The PMS was blended with MSW of 10%, 30%, 50%, 70% and 90%, which were named as 90M10P, 70M30P, 50M50P and 10M90P. The initial temperature, characteristic index, interaction and activation energy were studied in this paper. The initial temperature became higher with the increasing of PMS proportion and became lower when added the additives. The value of the comprehensive pyrolysis characteristic index of the blends indicated that 90M10P and70M30P were the suitable ratios for co-pyrolysis. There was significant interaction between MSW and PMS in high temperature. The average activated energy which calculated in the proportion of 90M10P showed that the MgO(5%) and AC(5%) were the preferable additives.

High Performance Magnesium Ion Electrolytes

Magnesium-ion based battery chemistries have been the subject of intense research because of the inherent high energy density of metallic magnesium anodes. One of the biggest complications that has limited the progress in this area is the development of electrolytes that facilitate the reversible deposition of magnesium metal. Current state of the art electrolytes are based on Grignard-derived magnesium compounds paired with Lewis acids such as aluminum chloride. A few notable exceptions utilize carborane structures as anions, which enable reversible electrochemistry. The presence of chloride ions in many electrolyte solutions has proven to be problematic because they cause pitting and corrode parts commonly used in coin cells. As such, it is imperative that researchers identify pathways that can result in halide-free electrolyte solutions. We have developed a new paradigm for magnesium ion electrolytes, utilizing a robust synthesis pathway that incorporates common reagents. The electrolyte has a large voltage window on stainless steel and aluminum (4-5 V vs. Mg), high conductivity (comparable with lithium ion electrolytes), and near unity Coulombic efficiency. We will discuss characterization of the electrolyte, identity of solution species, and promising methods of modifying the electrolyte for improved figures of merit.

Sensitive detection of proteins in polyacrylamide gel via isatoic anhydride derivatization: Introduction of a low-cost fluorescent prelabeling procedure.

Here, we introduce isatoic anhydride as a sensitive and commodious fluorescent prelabel for detection of proteins in one-dimensional polyacrylamide gels. High reactivity of isatoic anhydride with nucleophiles in mild alkaline environments makes it an appropriate tag for labeling of biomolecules. In this study, we show that preelectrophoresis labeling of proteins with isatoic anhydride for few minutes at room temperature allows detection of 2-4 ng of standard proteins, BSA and lysozyme, per band. Proteins were successfully labeled in the presence of a wide range of common biological reagents and in crude cell extract. The labeled proteins have the same electrophoretic migration in comparison to unlabeled proteins; however the application of saturation labeling method results in slight band broadening. Compatibility of the method with downstream processes was assessed by tryptic digestion of labeled proteins and study of peptide mixture using gel electrophoresis which revealed partial digestion of labeled proteins due to lysine modification. The present procedure is sensitive, rapid, and inexpensive and is a promising alternative for current protein staining procedures, where downstream processes are not desired.

Hypervalent iodine reagents for heterocycle synthesis and functionalization

Hypervalent iodine reagents for heterocycle synthesis and functionalization Jiyun Sun,1 Daisy Zhang-Negrerie,2 Yunfei Du,1 Kang Zhao,1 1Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 2Concordia International School Shanghai, Shanghai, People’s Republic of China Abstract: Hypervalent iodine reagents have been vastly applied in many significant oxidative reactions. This surging interest in iodine reagents is mainly due to the very useful oxidizing properties, combined with their benign environmental character and commercial availability. In this review, we focus on the representative transformations that used the common hypervalent iodine reagents as oxidants in heterocycle synthesis and functionalizations, based on the type of the hypervalent iodine reagents. Keywords: hypervalent iodine reagent, heterocycle synthesis, heterocycle functionalization, oxidative reaction

Strain-Promoted Cycloadditions for Development of Copper-Free Click Reactions

Noncatalyzed cycloadditions between strained alkynes or alkenes and 1,3-dipoles or dienes (copper-free click reactions) have emerged as powerful bioorthogonal transformations. Biomolecule labeling strategies based on applications of strain-promoted cycloaddition continue to garner considerable interest, and this chemistry is poised for rapid growth in the future. Metal-free click chemistry is also ideally suited to facilitate assembly or modification of functional materials, and so its use in materials chemistry is also expected to expand. This review examines the reactivity of the most common Cu-free click reagents currently employed: cyclooctynes, E-cyclooctenes, norbornenes, and cyclopropenes. Factors important in governing the reactivity of these strained π systems and approaches toward increasing the ability of these reagents to engage in spontaneous and selective cycloadditions with complementary dipoles/dienes are discussed. Keywords: Copper-free click, azide-alkyne cycloaddition, inverse electron demand cycloaddition, strain-promoted cycloaddition, cyclooctyne, trans-cyclooctene, tetrazine, cyclopropene.

An improved method for RNA extraction from urediniospores of and wheat leaves infected by an obligate fungal pathogen, Puccinia striiformis f. sp. tritici

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important wheat disease in China, seriously threatening wheat production. Understanding the winter survival of the fungus is a key for predicting the spring epidemics of the disease, which determines the crop loss. Estimation of P. striiformis f. sp. tritici winter survival requires processing a large number of samples for sensitive detection of the pathogen in wheat leaf tissue using real-time quantitative reverse transcription PCR (qRT-PCR). A bottleneck for the analysis is the acquisition of a good yield of high quality RNA suitable for qRT-PCR to distinguish dead and alive fungal hyphae inside leaves. Although several methods have been described in the literatures and commercial kits are available for RNA extraction, these methods are mostly too complicated, expensive and inefficient. Thus, we modified three previously reported RNA extraction methods with common and low-cost reagents (LiCl, SDS and NaCl) to solve the problems and selected the best to obtain high quality and quantity RNA for use in qRT-PCR. In the three improved methods, the NaCl method was proven to be the best for extracting RNA from urediniospores of and wheat leaves infected by P. striiformis f. sp. tritici, although the modified LiCl and SDS methods also increased yield of RNA compared to the previous methods. The improved NaCl method has the following advantages: 1) Complete transfer of urediniospores of P. striiformis f. sp. tritici from the mortar and pestle can ensure the initial amount of RNA for the qRT-PCR analysis; 2) the use of low-cost NaCl to replace more expensive Trizol can reduce the cost; 3) the yield and quality of RNA can be increased; 4) the improved method is more suitable for a large number and high quantity of samples from fields. Using the improved NaCl method, the amount of RNA was increased three times from urediniospores of P. striiformis f. sp. tritici compared from the extraction kit. Approximately, 10.11 μg total RNA of high quality was obtained from 100 mg of infected leaves, which was 8.8, 6.5, 3.4 and 2.1 folds of the amounts obtained from the previous LiCl, SDS, NaCl and traditional Trizol methods, respectively. The method could be used to study the overwintering rates of P. striiformis f. sp. tritici over a large region of wheat production for predicting epidemic levels by determining pathogen survival levels after winter. The method can also be used in any studies which need a large number of high quality RNA samples.

ChemInform Abstract: Synthetic Applications of Pseudocyclic Hypervalent Iodine Compounds

AbstractReview: 99 refs.

Charged tag founded in N-(1-chloroalkyl)pyridinium quaternization for quantification of fatty aldehydes

N-(1-chloroalkyl)pyridinium quaternization was developed for the derivatization of fatty aldehydes. Differing from common pre-charged reagents, non-charged pyridine and thionyl chloride were designed to add permanently charged tag on aldehydes. Pyridine was far less competitive than charged derivatives in ionization. Thionyl chloride in excess was quenched by deionized water, converting into less residual sulfur dioxide bubbles. Thus solutions could be tested directly by mass spectrometry without further post-treatments. Pyridine-d5 labeled fatty aldehydes were prepared as internal standards. Mixed derivatives were then analyzed by high performance liquid chromatography coupled to positive electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analytical parameters including reaction yield, stability, precision, linearity, and detection limits (LODs < 0.3 pg mL−1) were carefully validated. This method facilitated the analysis low content (ng mL−1) levels of free aliphatic aldehydes (C6C18) in human thyroid carcinoma and para-carcinoma tissue with a simple pretreatment procedure. Content of long chain nonvolatile aldehydes (C10C18) remarkably increased in thyroid carcinoma tissues (p < 0.05).

Studying Equilibrium in the Chemical Reaction between Ferric and Iodide Ions in Solution Using a Simple and Inexpensive Approach

A laboratory experiment on the study of the chemical equilibrium based on the reaction between ferric and iodide ions in solution with the formation of ferrous ions, free iodine, and triiodide ions is developed. The total concentration of iodide and triiodide ions in the reaction mixture during the reaction is determined by the argentometric titration; the concentrations of the other reagents and products are calculated using the material balance equations. The dependence of the equilibrium constant on temperature is also considered. The average values of Kc are 2.5 × 104 M–1 (35 °C) and 4.5 × 104 M–1 (45 °C). The experiment uses common reagents and simple equipment and can be performed in any educational laboratory. The basic procedure of processing the experimental data is quite simple and can be easily performed even by first-year students; however, the experiment can be extended in several ways to be suitable for advanced laboratory courses for upper-year undergraduates. Possible extensions are discus...

Acrylic Triblock Copolymers Incorporating Isosorbide for Pressure Sensitive Adhesives

A new monomer acetylated acrylic isosorbide (AAI) was prepared in two steps using common reagents without the need for column chromatography. Free radical polymerization of AAI afforded poly(acetylated acrylic isosorbide) (PAAI), which exhibited a glass transition temperature (Tg) = 95 °C and good thermal stability (Td, 5% weight loss; N2 = 331 °C, air = 291 °C). A series of ABA triblock copolymers with either poly(n-butyl acrylate) (PnBA) or poly(2-ethylhexyl acrylate) (PEHA) as the low Tg midblocks and PAAI as the high Tg end blocks were prepared using Reversible Addition–Fragmentation chain Transfer (RAFT) polymerization. The triblock copolymers ranging from 8–24 wt % PAAI were evaluated as pressure sensitive adhesives by 180° peel, loop tack, and static shear testing. While the PAAI-PEHA-PAAI series exhibited poor adhesive qualities, the PAAI-PnBA-PAAI series of triblock copolymers demonstrated peel forces up to 2.9 N cm–1, tack forces up to 3.2 N cm–1, and no shear failure up to 10 000 min. Dynamic m...

Bioluminescence imaging in live cells and animals.

The use of bioluminescent reporters in neuroscience research continues to grow at a rapid pace as their applications and unique advantages over conventional fluorescent reporters become more appreciated. Here, we describe practical methods and principles for detecting and imaging bioluminescence from live cells and animals. We systematically tested various components of our conventional fluorescence microscope to optimize it for long-term bioluminescence imaging. High-resolution bioluminescence images from live neurons were obtained with our microscope setup, which could be continuously captured for several hours with no signs of phototoxicity. Bioluminescence from the mouse brain was also imaged noninvasively through the intact skull with a conventional luminescence imager. These methods demonstrate how bioluminescence can be routinely detected and measured from live cells and animals in a cost-effective way with common reagents and equipment.

2-Hydrazinoquinoline: a reactive matrix for matrix-assisted laser desorption/ionization mass spectrometry to detect gaseous carbonyl compounds.

The sensitivity, range of applications, and reaction mechanism of 2-hydrazinoquinoline as a reactive matrix for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) were examined. Using a reaction chamber (125L) equipped with a stirring fan and a window for moving the MALDI-MS plate and volatile samples in and out, the sensitivities of 2-hydrazinoquinoline to gaseous aldehydes (formaldehyde, acetaldehyde, propionaldehyde, and n-butyraldehyde) and ketones (acetone, methyl ethyl ketone, and methyl isobutyl ketone) were determined to be at least parts per million (ppm) levels. On the other hand, carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid) and esters (ethyl acetate, pentyl acetate, isoamyl acetate, and methyl salicylate) could not be detected by 2-hydrazinoquinoline in MALDI-MS. In addition to 2,4-dinitrophenylhydrazine, a common derivatization reagent for analyzing carbonyl compounds quantitatively in gas chromatography and liquid chromatography, the dissolution of 2-hydrazinoquinoline in an acidic solution, such as trifluoroacetic acid, was essential for its function as a reactive matrix for MALDI- MS.

MoV Reagents in Organic Synthesis

AbstractThe use of MoV reagents, and in particular MoCl5, in organic synthesis is surveyed. The oxidative treatment of aromatic substrates is the most common application. The unique properties of these reagents are due to their high oxidative power combined with exquisite Lewis acid properties. In several examples MoV reagents outperform other common oxidative coupling reagents. C–C bond formation through inter‐ and intramolecular oxidative coupling can lead to selective formation of five‐ to eight‐membered ring systems. Mechanistic investigations of the courses of reactions involving MoV reagents and aromatic substrates indicate that radical cations are initially formed, entering the oxidative coupling scenery. Mechanistic studies reveal that Scholl‐type conversion is unlikely. However, over‐oxidation of the product seems to be the rationale for the selective conversion. Reduction occurs during workup, through the action of the lower‐valency molybdenum salts present. This opens up the pathway to oxidative domino sequences. MoCl5 has already been used in the key steps of the syntheses of several natural products or their analogues. In addition, MoCl5 can serve in chlorination reactions and in stereoselective isomerization by template formation, and also as a precursor for alkyne trimerization.

Rapid diagnosis of common deletional α-thalassemia in the Chinese population by qPCR based on identical primer homologous fragments

ObjectiveIn China, −SEA, −α3.7 and −α4.2 are common deletional α-thalassemia alleles. Gap-PCR is the currently used detection method for these alleles, whose disadvantages include time-consuming procedure and increased potential for PCR product contamination. Therefore, this detection method needs to be improved. Based on identical-primer homologous fragments, a qPCR system was developed for deletional α-thalassemia genotyping, which was composed of a group of quantitatively-related primers and their corresponding probes plus two groups of qualitatively-related primers and their corresponding probes. In order to verify the accuracy of the qPCR system, known genotype samples and random samples are employed. ResultThe standard curve result demonstrated that designed primers and probes all yielded good amplification efficiency. In the tests of known genotype samples and random samples, sample detection results were consistent with verification results. ConclusionsIn detecting αα, −SEA, −α3.7 and −α4.2 alleles, deletional α-thalassemia alleles are accurately detected by this method. In addition, this method is provided with a wider detection range, greater speed and reduced PCR product contamination risk when compared with current common gap-PCR detection reagents.

Photopolymerization of coordinated ionic liquid monomers: Realizing the benefits of structured media using only common reagents

Here, we provide a detailed report on a new type of structured media for improving photopolymerizations: coordinated ionic liquids (ILs). Coordinated ILs are readily formed from the bistriflimide ([Tf2N]−) anion and coordination complexes composed of Li+ cations with polar organic monomers without an additional cosolvent. Photopolymerization kinetics and monomer conversion were monitored in real time using attenuated total reflectance Fourier transform infrared spectroscopy and the material properties of the products were examined using gel permeation chromatography and differential scanning calorimetry. Generally, coordinated IL monomers displayed improved reaction kinetics at both high and low salt concentrations as well as distinct product properties. The noncovalent (and reversible) interactions between monomer and salt in coordinated ILs hold promise as an efficient and versatile form of structured media for photopolymerizations. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2004–2014

Harmonizing the International Normalized Ratio (INR) : Standardization of Methods and Use of Novel Strategies to Reduce Interlaboratory Variation and Bias.

To reduce interlaboratory variation and bias in international normalized ratio (INR) results, as used to monitor patients receiving vitamin K antagonist therapy, including warfarin, in a large pathology network (n = 27 laboratories) by procedural standardization and harmonization. Network consensus to standardize to common instrument and reagent platforms was established, following development of hemostasis test specifications. Subsequent installations and implementation occurred after conclusion of a government tender process. Network-wide application of simple novel process of verification harmonization of local international sensitive index and mean normal prothrombin time initiated for each new lot of INR reagent that does not require ongoing use of reference thromboplastin or calibration/certified plasma sets. We achieved reduction of different instrument manufacturers (from four to one), instrument types (10 to three), reagent types (four to one), and instrument/reagent combinations (12 to three), plus substantial reduction in INR variability and bias. Results infer significant improvement in local patient management, with positive implications for other laboratories. For the United States in particular, lack of US Food and Drug Administration-cleared certified plasmas may compromise INR accuracy, and our novel approach may provide a workable alternative for laboratories and networks.

Tunable luminescence of nanoporous silicon via electrochemical etching parameters

This paper reports the surface state induces a variation in light emission of nanoporous Si as a function of electrolyte condition, anode–cathode distance and aging in common chemical reagents to achieve strong and stable luminescence of Si semiconductor. The electrochemical derived nano Si was observed to have a nanoporous structure with the pore of about 20nm in the thickness of 50μm. The luminescence of nanoporous Si was showed enhancing in the sample with the HF/ethanol of 1:1 and the anode–cathode distance of about 5cm. As etched specimen, the luminescence of the nanoporous Si was centered at 800nm; however blue-shift when they were immersed in green chemical reagents. These results suggest that the potential application of electrochemical etching followed by green chemical treatment to tunable luminescence, which was potential application in nanoporous Si based devices and nanomedicine.

Benzylic rearrangement stable isotope labeling for quantitation of guanidino and ureido compounds in thyroid tissues by liquid chromatography-electrospray ionization mass spectrometry

Benzylic rearrangement stable isotope labeling (BRSIL) was explored to quantify the guanidino and ureido compounds (GCs and UCs). This method employed a common reagent, benzil, to label the guanidino and ureido groups through nucleophilic attacking then benzylic migrating. The use of BRSIL was investigated in the analysis of five GCs (creatine, l-arginine, homoarginine, 4-guanidinobutyric acid, and methylguanidine) and two UCs (urea and citrulline). The labeling was found simple and specific. The introduction of bi-phenyl group and the generation of nitrogen heterocyclic ring in the benzil-d0/d5 labeled GCs and UCs improved the retention behaviors in liquid chromatography (LC) and increased the sensitivity of electrospray ionization mass spectrometry (ESI MS) detection. The fragment ion pairs of m/z 182/187 and m/z 210/215 from the benzil-d0/d5 tags facilitated the discovery of potential GCs and UCs candidates residing in biological matrices. The use of BRSIL combined with LC-ESI MS was applied for simultaneously quantitation of GCs and UCs in thyroid tissues. It was demonstrated that nine GCs and UCs were detected, six of which were further quantified based on corresponding standards. It was concluded that five GCs and UCs (l-arginine, homoarginine, 4-guanidinobutyric acid, methylguanidine, and citrulline) were statistically significantly different (p < 0.05) between the para-carcinoma and carcinoma thyroid tissue samples.

Strategies for the Synthesis of Thiazolidinone Heterocycles

Thiazolidinones is the special class of heterocyclic compounds with a broad spectrum of biological activities such as anti-inflammatory, antiproliferative, antihistaminic, anti-HIV, hypnotic, anaesthetic, antifungal, anthelmintic and antiviral agents as well as CNS stimulants. Therefore researchers have synthesized these condensed heterocycles through different complex pathways as target structures for biological studies. This review focuses on the various strategies followed for the convenient synthesis of thiazolidinone based heterocyclic derivatives. The steps included condensation followed by cyclization of Schiff’s bases, either in a step-wise manner or in one pot under different conditions. Mercaptoacetic acid, thiolactic acid, chloroacetyl chloride, potassium thiocyanate, ethylchloro acetate and ammonium thiocyanate are the most common reagents used for the synthesis thiazolidinone appended on different heterocyclic skeletons.