Non-hazardous Reagents Research Articles

NaHCO3‐promoted Formal [4+3] Annulation of Salicylaldehydes with Isoquinolinium Salts Accessing Isoquinoline‐fused Benzo[f][1,3]oxazepines

A concise and practical sustainable strategy for modular access to isoquinoline‐fused benzo[f][1,3]oxazepine derivatives through a formal [4+3] annulation of commercially available salicyaldehydes with isoquinolinium salts has been developed. The reactions proceeded through the formation of two new bonds (C=C and C‐O) and a seven‐membered heterocyclic ring in one pot. Remarkably, use of simple NaHCO3 as a mild base, open atmosphere, nonhazardous reagents, nice functional group tolerance, and easily scale up are added characteristics to this approach. A wide range of substrates are compatible with this mild reaction system, thereby proving a facile and reliable protocol for constructing a benzo[f][1,3]oxazepine skeletons.

Metal-free [3+3] heteroannulation of thioamides with alkynyl NHPI-esters to access 2H-1,3-thiazin-4(3H)-ones

The first chemo- and regioselective one-pot convergent synthesis of 2H-1,3-thiazin-4(3H)-ones has been successfully realized employing β-ketothioamides and alkyne derivatives of N-hydroxyphthalimide (NHPI)-ester under mild conditions in good to excellent yields. The process is triggered by the in-situ generation of dienolate intermediate followed by intramolecular selective N-cyclization. Remarkably, metal- and additive-free conditions, an open atmosphere, non-hazardous reagents, and easy purification are added characteristics to this cascade [3 + 3] annulative strategy. This heteroannulative approach will not only provide an effective method to access various 1,3-thiazin-4-ones but also augment the research domain of thioamides.

Metal-Free One-Pot Annulative Coupling of 2-Hydroxybenzaldehydes with β-Ketothioamides: Access to Diverse 2-Arylimino-2H-Chromenes.

A concise and practical one-pot sustainable approach for expedient synthesis of 2-arylimino-2H-chromenes by two-component cascade [4 + 2] annulative coupling of easily available 2-hydroxybenzaldehydes with β-ketothioamides has been developed in good yields for the first time. Remarkably, metal- and additive-free conditions, use of simple K2CO3 as a mild base, open atmosphere, exclusive regioselectivity, step/atom economy, nonhazardous reagents, and easy purification are added characteristics to the strategy. This annulative protocol will not only provide an efficient method to access diverse chromene scaffolds, but also enrich the research domain of β-ketothioamides.

Effect of solvent and additives on the electrospinnability of BSA solutions

Electrospun nanofibrous membranes have attracted the interest of the scientific community over the past decades due to their unique properties (e.g., high surface area, enzyme encapsulation high efficiency in filtering). Among the most promising membranes are those derived from natural polymers, which are not based on fossil fuels and most of them are highly biocompatible. In this regard, this study is focused on the development and characterization of electrospun nanofibrous membranes of bovine serum albumin (BSA) with potential applications in several fields, from tissue engineering to advanced filtering. Although the globular structure of BSA hinders the generation of nanofibers, some previous studies have succeeded in its electrospinning. However, they made use of either toxic reagents or co-electrospinning with synthetic polymers, which resulted in poorer biocompatibility. To prevent this, the present study explores the impact of non-hazardous reagents on the formation of BSA nanofibers. As a result, it was observed that the addition of ethanol (EtOH) in the solvent mixture and the thermal denaturation of BSA favored the electrospraying of nanoparticles (∼ 300 nm). It was also noticed that the presence of hydroxypropyl methylcellulose (HPMC) favors the formation of nanofibers (∼ 60 nm). However, bead formation was found in these membranes. This work contributes to clarifying the influence of solvents and surfactants when proteins are electrospun, enabling the manufacture of bio-based nanofibrous mats with applications in different fields (e.g., filtering, biomaterials, active packaging).

Lab-at-Home: Hands-On Green Analytical Chemistry Laboratory for New Normal Experimentation

The COVID-19 pandemic has forced analytical chemistry educators in Thailand to change methods of teaching and learning to new normal ones. Higher education has faced additional challenges because of a lack of hands-on experiments and an increasing number of students in foundation chemistry courses being hindered from practicing skills. This work aimed to develop a Lab-at-Home (LAH) for new normal, analytical chemistry experimentation. The LAH implemented a hands-on green chemistry experiment, i.e., colorimetric determination of iron using non-hazardous reagents (supporting Sustainable Development Goal (SDG) 12-responsible consumption and production). The LAH was sent to students at their location before the synchronous class, where the instructors were prompt to supervise. Thus, this supports SDG4-quality education and SDG10-reduced inequalities. The learning outcome achievements, i.e., the analytical characteristics and colorimetry principles comprehension, as well as the ability to perform data analysis, were evaluated by a quiz and laboratory report. LAH satisfaction was assessed by questionnaire and focus group discussion. The learning outcomes were successfully achieved, although students who performed the experiment individually received higher scores than those who did in groups. Students were very satisfied with the LAH as a tool for new normal experimentation, yet some students faced a poor Internet connection during the synchronous online class.

Diarylation of N- and O-nucleophiles through a metal-free cascade reaction

Diarylation of N- and O-nucleophiles through a metal-free cascade reaction

The Depression and Adsorption Mechanism of Polyglutamic Acid on Chalcopyrite and Pyrrhotite Flotation Systems

The rejection of pyrrhotite and pyrite has become a long-standing problem in the copper ore industry. This paper describes the first successful depression and adsorption mechanism of a novel and non-hazardous reagent, polyglutamic acid (PGA), on pyrrhotite in the selective flotation of chalcopyrite with xanthate as the collector, making use of various laboratory-scale measurement techniques. The addition of PGA inhibited the flotation of pyrrhotite much more strongly than that of the chalcopyrite in a wide pH range. The prior addition of PGA achieved an improved selective flotation of chalcopyrite from pyrrhotite at pH 8, at which the grade and recovery of chalcopyrite in concentrate were over 80%. Surface measurement techniques including XPS spectral, IR spectral, zeta potential, and reagent adsorption analyses indicated that the PGA interacted differently with the two minerals, and had much greater affinity towards pyrrhotite than chalcopyrite. The presence of PGA blocked the electrochemical activity of the collector on the pyrrhotite surface and thus depressed its flotation, whereas the adsorption of the collector and its oxidation to dixanthogen were more effective on the chalcopyrite surface, indicating a weaker interaction of PGA with chalcopyrite. Our results suggest that the application of PGA could replace the toxic inorganic depressants in flotation technology, and could significantly reduce the environmental impacts of processing.

Mukaiyama reagent/NaNO2/wet SiO2 as a mild and heterogeneous reagent system for the N-nitrosation of amines and preparation of azides from hydrazines

The combination of the Mukaiyama reagent and sodium nitrite in the presence of wet SiO2 was found to be an effective system for the conversion of amines into N-nitrosamines and hydrazines into azides. The heterogeneous reaction proceeded in good to excellent yields and possesses advantages such as the use of non-hazardous reagents, and simple reaction work-up.

Learning about Structural and Optical Properties of Organic Compounds through Preparation of Functional Nanomicelles while Avoiding Hazardous Chemicals or Complicated Apparatus

The synthesis of nanomicelles in the aqueous phase on the basis of nonhazardous detergents is described where azulene and a naphthalene tetracarboximide are used in this experiment to teach the relation between structural and optical properties of organic compounds and point out possible applications. The experiment covers many aspects of modern-day chemistry; a simple handling of nonhazardous reagents makes the system suitable for basic chemical education even for comparably moderately skilled persons.

A simple and efficient genomic DNA extraction protocol for large scale genetic analyses of plant biological systems

Extraction of high quality genomic DNA from higher plants is hindered by the presence of secondary metabolites, which reduce the yield and quality of the DNA. We describe an alternative protocol for genomic DNA extraction from fresh and dry plant leaves that is amenable to PCR-based genetic analysis. Existing methods were either very lengthy, expensive or not suitable for extraction of genomic DNA from dry leaves. Our method used SDS and high salt concentrations to extract DNA and does not require use of hazardous materials or special laboratory equipment. Genomic DNA extracted using our method was used for PCR-based genetic characterization of different varieties of cashew trees, Anacardium occidentale, via SSR markers as well as Zea mays varieties. This protocol improves existing methods in that it has the advantage of being adaptable to studies with a large number of samples and limited resources. The method is rapid, cost efficient and uses non-hazardous reagents. Genomic DNA extracted using this method has sufficient quality for downstream PCR-based genetic analysis.

Solution Synthesis of BiFeO3 Thin Films onto Silicon Substrates with Ferroelectric, Magnetic, and Optical Functionalities

Single‐BiFeO3 perovskite films onto Pt‐coated silicon substrates have been fabricated by chemical solution deposition using a synthesis strategy based on the use of nonhazardous reagents. Different routes were tested to obtain precursors for the deposition of the films, inferring that bismuth (III) nitrate and iron (III) 2,4‐pentanedionate dissolved in acetic acid and 1,3‐propendiol led to the best solution. Ferroelectric, magnetic, and optical functionalities were demonstrated in these films, obtaining a high ferroelectric polarization at room temperature, ~67 μC × cm−2, a dependence of the magnetization with the film thickness, 0.60 and 2.50 emu × g−1 for the ~215 and ~42‐nm‐thick films, and a direct band gap in the visible range, Eg ~2.82 eV. These results support the interest of solution methods for the fabrication of BiFeO3 thin films onto the silicon substrates required in microelectronic devices.

A simplified arthropod genomic-DNA extraction protocol for polymerase chain reaction (PCR)-based specimen identification through barcoding

Genomic DNA extraction protocols generally require the use of expensive and hazardous reagents necessary for decontamination of phenolic compounds from the extracts. In addition, they are lengthy, hindering large-scale sample extractions necessary for high-throughput analyses. Here we describe a simple, time and cost-efficient method for genomic DNA extraction from insects. The extracted DNA was successfully used in a Polymerase Chain Reaction (PCR), making it suitable for automation for large-scale genetic analysis and barcoding studies. The protocol employs a single purification step to remove polysaccharides and other contaminating compounds using a non-hazardous reagent buffer. In addition, we conducted a bioinformatics database analysis as proof of concept for the efficiency of the DNA extraction protocol by using universal barcoding primers specific for cytochrome c oxidase I gene to identify different arthropod specimens through Barcode of Life Database (BOLD) database search. The usefulness of this protocol in various molecular biology and biodiversity studies is further discussed.

An Inexpensive, Simple Protocol for DNA Isolation from Blood for High-Throughput Genotyping by Polymerase Chain Reaction or Restriction Endonuclease Digestion

We describe simple, inexpensive, and reliable methods for isolating DNA from avian blood, semen, or feather pulp. The procedures are readily applicable to high-throughput 96-well plate isolation for genotype analysis of chicken DNA based on restriction endonuclease digestion or PCR. Isolation cost is primarily the cost of a deep-well assay block and a few pipet tips; current price is less than 0.10 dollar per sample, providing a significant cost advantage over commercial kits. The procedure employs inexpensive, nonhazardous reagents and yields intact, double-stranded DNA from as little as 2 to 10 microL of avian blood, suitable for RFLP analysis or hundreds of PCR amplifications. We compared our method to published procedures for alkaline extraction from feather pulp and found our method to be more reliable with the advantage of isolating intact DNA sequences that can be easily quantified. With minor modifications, the method can isolate DNA for PCR genotyping from mammalian whole blood.

An assay for N-glycosylase activity on single-stranded DNA using stable, nonhazardous reagents

An assay for N-glycosylase activity on single-stranded DNA using stable, nonhazardous reagents

Evaluation of Soil DNA from Arable Land in Japan Using a Modified Direct-extraction Method

Using a widely used commercial DNA extraction kit and a newly modified direct DNA extraction method proposed in this report, soil DNA was extracted from arable land in diverse geological locations in Japan and the quality and quantity of the DNA were examined. A modified direct DNA extraction method was developed, consisting of one-step extraction and two-step purification using potassium acetate and a DEAE-cellulose column, respectively, and designated as a DSPD (Differential Salt Precipitation and DEAE-cellulose) method. The total time needed to process six soil samples with this method was less than two hours, including the time taken to set up the DEAE-cellulose columns. Other advantages of our DSPD method are the use of non-hazardous reagents and running costs only 5-10% of the commercial kits currently used in soil microbiological research. This DSPD method was tested using 24 soil samples collected from diverse locations in Japan and showed that it is a reliable technique for DNA extraction from a wide range of soil types when compared with commercial DNA extraction kits. This DSPD method will therefore contribute to the molecular and genomic analyses of microbial populations and ecosystems that require numerous samples of soil DNA.

Development of a Practical, Safe, and High-Yielding Process for the Preparation of Enantiomerically Pure trans-Cyclopropane Carboxylic Acid

A practical, safe, and high-yielding process for the cyclopropanation of a chiral epoxide has been developed using the inexpensive and nonhazardous reagents triethylphosphonoacetate and sodium tert-butoxide.

Synthesis of Quinazolin-4-(3h)-ones from O-Amidobenzonitriles Using Urea-hydrogen Peroxide1

Synthesis of quinazolin-4-(3H)-ones from o-amidobenzonitriles has been carried out by using urea-hydrogen peroxide as a mild, stable and non-hazardous reagent.

Chemiluminescent and bioluminescent techniques

Light-emitting chemical reactions (chemiluminescence, CL) and biological reactions (bioluminescence, BL) have a diverse range of analytical applications but relatively few have been adopted by routine clinical laboratories. Advantages of CL and BL assays include sensitivity (attomole and sub-attomole detection limits), speed (signal generated in a few seconds and in some cases stable for several hours), nonhazardous reagents, and simple procedures. The most promising clinical applications are in immunoassay, protein blotting, and DNA probe assays. Chemiluminescent molecules exploited as labels include luminol, isoluminol, acridinium esters, thioesters and sulfonamides, and phenanthridinium esters. Separation and nonseparation assays have been devised, based on isoluminol and acridinium ester labels. The combination of the amplification properties of an enzyme and a CL or BL detection reaction provides a highly sensitive analytical system. Since 1983, CL and BL methods have been developed for many enzyme labels, e.g., alkaline phosphatase, glucose-6-phosphate dehydrogenase, horseradish peroxidase, Renilla luciferase, and xanthine oxidase. Currently, the most successful enzyme assays are the enhanced CL method for a peroxidase label involving a mixture of luminol, hydrogen peroxide, and an enhancer (e.g., p-iodophenol) and the direct CL method for alkaline phosphatase, with an adamantyl 1,2-dioxetane phenyl phosphate as substrate. Both systems are very sensitive (the detection limit for alkaline phosphatase when using the dioxetane reagent is 0.001 amol) and produce long-lived light emission (greater than 30 min), which is ideal for membrane applications in which light emission is detected with photographic film or a charge-coupled device camera.