Syntheses of DL-threo-Thiamphenicol via Green Oxidation

IntroductionAqueous hydrogen peroxide is considered to be a“green”oxidant with a high oxidation efficiency due toits low molecular weight,cleanness in the oxidationprocess in which only harmless water is produced,lowcost of production and safe transport…     

A Facile and Green Synthesis of Sulforaphane

Sulforaphane (1, SFN), 4-methylsulfinylbutyl isothiocyanate, was considered as the most potent inducer of phase II enzymes proteins [glutathione transferases (GSTs) and NAD(P)H: quinone reductase (QR)] selectively, and strong inhibitor of phase I enzymes …     

Scale Inhibition of Green Inhibitor Polyepoxysuccinic Sodium

Polyepoxysuccinic acid (PESA) is the green water treatment agents recognized all over the world[1-3]. It is found that when PESA is used alone, it had good scale inhibition. PESA should be included in the category of green scale inhibitor. PESA is synthesized with maleicanhydride in the presence of catalysts. The effect on scale-in-hibiting property of the product from amount and feed times of catalyst, the reaction temperature, the reaction time were investigated. The optimum reaction c…     

Research and Practice in Green Chemical Technologies

Green chemistry is also called environment harmless or environment friendly chemistry. Green chemistry requires to use new synthetic methods, engineering technologies and processes to eliminate or reduce by-products, wastes or products that harmful to human health, community safety, and ecology environment. Green chemistry pursues to control the usage of the harmful and toxic materials, reduce waste emission, avoid necessity to treat the wastes; Green Chemistry advocates wastes management from…     

A Green Synthesis of Diisopropyl Phosphoryl Amino Acid

In this paper,we report that diisopropyl phosphoryl amino acid be prepared with reasonable yields under solvent-free condition by adding amino acid to the mixture of diisopropyl phosphite and N-chlorodiisopropylamine.     

Green Synthetic Method for 1,5‐Disubstituted Carbohydrazones

A green synthetic method for 1,5‐disubstituted carbohydrazones is described. The reaction of dimethyl carbonate with hydrazine hydrate first gave carbohydrazide, which further reacted with various aromatic aldehydes or aliphatic ketones under solvent‐free conditions to efficiently afford 1,5‐disubstituted carbohydrazone. This protocol has the advantages of using nontoxic dimethyl carbonate as starting material, no use of organic solvents, short reaction time, high yield, and simple workup procedure.     

Corrosion Inhibition of a Green Scale Inhibitor Polyepoxysuccinic Acid

The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect betweenPESA and Zn2 or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2 and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic     

Novel and Gram‐Scale Green Synthesis of Flutamide

Isobutyric acid in the presence of cyanuric chloride and N‐methylmorpholine was converted into active ester 3 at 0–5 °C, and it was subsequently treated with 3‐aminobenzotrifluoride 4 at 25 °C to furnish corresponding amide 5. This amide finally, on nitration, produced the desired product flutamide, 2‐methyl‐N‐[4‐nitro‐3‐(trifluoromethyl)phenyl]propionamide 6 in good yield. By‐product 2,4,6‐trihydroxy‐1,3,5‐triazine 7 was converted into the useful starting material cyanuric chloride 1 by refluxing with N,N‐diethylamine and POCl₃.     

‘Green’ immunochromatographic electrochemical biosensor for mercury(II)

We describe an immunochromatographic electrochemical biosensor (IEB) for highly specific and sensitive determination of Hg(II) ions. The IEB is based on the use of a new monoclonal antibody (McAb) against Hg(II) ions that affects the recognition of an antigen. The McAb is placed on the surface of gold nanoparticles (AuNPs) and can recognize the antigen only in the absence of Hg(II) ions. This detection scheme was used to design an immunochromatographic test strip using dually labeled AuNPs along with electrochemical detection. Signal amplification was accomplished by a competitive reaction and the use of horseradish peroxidase. Following immunochromatography, the test zone was cut out and transferred into a reaction cell loaded with a substrate solution containing ortho-phenylenediamine and H₂O₂. After 10-min incubation with horseradish peroxidase, square wave voltammetry was performed with a screen-printed electrode. Under optimal conditions and a working voltage of ?0.57 V, the IEB displays a linear response in the 0.1 to 200 ng.mL^?1 Hg(II) concentration range and a 30 pg.mL^?1 limit of detection. It was applied to the determination of Hg(II) in (spiked) waters and milk where its sensitivity by far surpassed the maximum allowed contamination levels. This sensitive IEB therefore possesses substantial advantages over other assays. In addition, the detection scheme may be extended to other metal ions for which appropriate antibodies are available.

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Graphical abstract We developed an immunochromatographic electrochemical biosensor (IEB) for highly specific and sensitive determination of Hg(II) ions in water and milk by using a new anti-Hg²⁺ monoclonal antibody (McAb). The linear range and limit of detection is 0.1–200 ng·mL^?1 and 30 pg.mL^?1, respectively.

     

“The hidden power and competitive advantage of applying green chemistry metrics”

Green chemistry (GC) metrics provide insight into the relative waste, time and cost implications of pharmaceutical chemical processes and serve to guide scientists in the strategic application of resources to develop more efficient and sustainable processes. Examples of the application of GC metrics in evaluating pharmaceutical process efficiency and the subsequent development toward improvement exist in abundance from journals such as Organic Process Research and Development, Green Chemistry, or as encompassed by the winning examples from the ACS GCI Pharmaceutical Roundtable's [1] Peter J. Dunn award [2] or the US EPA's Green Chemistry Challenge award [3]. By their nature, GC metrics are continuously evolving but justify the necessary, unceasing investment in understanding and application as they offer unique, opportunistic insight serving to guide scientific resource deployment when developing greener pharmaceutical, chemical processes.     

Green synthesis of novel (E)-2-(1,4-dioxo-1,2,3,4-tetrahydrophthalazine-2-carbonyl)-3-(1H-indol-3-yl)acrylonitriles

Green synthesis of novel title compounds (6) has been developed from 3-(1,4-dioxo-3,4-dihydrophthalazin-(1H)-yl)-3-oxopropanenitrile (3) and indole-3-aldehyde (4) using Knoevenagel condensation followed by alkylation with alkylating agents. Compound 6 could also be synthesised by alkylation of 4 followed by condensation with 3. In an alternate sequence of reactions, 6 could be synthesised either from treatment of 3 with N,N-dimethylformamide dimethyl acetal to form (E)-3-(dimethlamino)-2-(1,4-dioxo-1,2,3,4-tetrahydrophthalazine-2-carbonyl)acrylonitrile 8 followed by reaction with 10 or by the reaction 8 with 9 followed by alkylation.     

Ecofriendly appraisal of stability-indicating high-performance chromatographic assay of canagliflozin and metformin with their toxic impurities; in silico toxicity prediction

Canagliflozin is an oral hypoglycemic drug recently formulated in combination with a biguanide, metformin hydrochloride, for improving its hypoglycemic action. Canagliflozin has one reported major degradation product, also metformin hydrochloride has one reported major degradation product, cyanoguanidine, and has a potential toxic impurity, melamine, that is reported to cause crystalluria that causes chronic kidney inflammation and nephrolithiasis leading to a renal failure. As per International Conference of Harmonization guidelines; a drug degradation product is classified as a type of drug impurities. Toxicity profiles of canagliflozin and metformin major degradation products were studied where in silico data disclosed toxicity too; the development of a specific chromatographic thin layer chromatographic assay was a must for quantification of such toxic related components along with the drugs in laboratory-prepared mixtures as a superior study. The proposed method was validated as per the International Conference of Harmonization and applied for the assay of Vokanamet tablets. The separation was achieved using acetone:ethyl acetate:acetic acid (8:2:0.2, by volume) as scanning eluted bands at 205 nm. For minimal environmental impact; greenness profile appraisal of the proposed assay was performed by three greenness assessment approaches; analytical Eco-Scale, Green Analytical Procedure Index, and Greenness metric approaches.     

Gramicidin S Derivatives Containing cis‐ and trans‐Morpholine Amino Acids (MAAs) as Turn Mimetics

The cyclic decapeptide gramicidin S (GS) was used as a model for the evaluation of four turn mimetics. For this purpose, one of the D ‐Phe‐Pro two‐residue turn motifs in the rigid cyclic β‐hairpin structure of GS was replaced with morpholine amino acids (MAA 2 – 5 ), differing in stereochemistry and length of the side‐chain. The conformational properties of the thus obtained GS analogues ( 6 – 9 ) was assessed by using NMR spectroscopy and X‐ray crystallography, and correlated with their biological properties (antimicrobial and hemolytic activity). We show that compound 8 , containing the dipeptide isostere trans‐MAA 4 , has an apparent high structural resemblance with GS and that its antibacterial activity against a panel of Gram positive and ‐negative bacterial strains is better than the derivatives 6 , 7 and 9 .     

An integrated vision of the Green Chemistry evolution along 25 years

The objective of the present review on the evolution of Green Chemistry (GC), since its emergence until 2016 (25th anniversary), aimed an integrated vision of its progress along the three phases of its development: emergence, divulgation and consolidation. The methodology involved the analysis of a selection of bibliography on the evolution of GC collected from issues of the ACS symposia series; editorials in specialized GC journals; and commemorative birthday papers/editorials of these journals and of the GC itself. The analysis allowed to identify and discuss the characteristics and conceptions of GC agents about fundamental concepts and procedures, in order to visualize and better understand the state of knowledge and the subject areas that make up the field. The main alterations identified in the evolution of GC were: it acquired a better defined identity, with more participation of academy and increased scope; was progressively framed in sustainability; has been aspiring to a holistic frame (but it is still dominated by its original reductionism) and to a change on the nature of the innovation for its implementation, from incremental to transformative. The analysis suggests that for supporting expansion and consolidation of GC the following aspects deserve attention: full validation of chemical greenness by metrics; better characterization of the frontiers of GC research areas/themes; increased integration between academy and industry; and penetration in chemistry curricula. Its basic philosophy being the practice of a chemistry more focused on the environment preservation, GC means a new stage in nature and in the history of Chemistry.

     

Extractive Spectrophotometric Determination of Ondansetron by Ion-Pair Formation with Bromocresol Green

Abstract

An empirical spectrophotometric procedure for the determination of the antiemetic ondansetron is carried out. The method is based on the formation of a 1:1 ion pair with bromocresol green in the pH range over 3.2 – 4.4, extraction into chloroform layer and spectrophotometric measurement at 420.8 nm. The calibration graph is linear over the range 0.1 – 20 μg ml^?1 ondansetron, with a relative standard deviation of 2.7%; the influence of foreign substances is also studied. The method is applied to ondansetron determination in human urine.     

Zinc hyperaccumulating plants as renewable resources for the chlorination process of alcohols

Abstract

Green Lucas reagent was prepared from Zinc hyperaccumulating plant, Thlaspi caerulescens. It is an effective and reusable reagent for the chlorination of tertiary, secondary, and primary alcohols. The results are the first use of contaminated biomass in organic synthesis and can constitute an encouragement for the economic development of phytoextraction and remediation programs for metal-bearing soils.     

Design of Organic Transformations at Ambient Conditions: Our Sincere Efforts to the Cause of Green Chemistry Practice

This account summarizes our recent efforts in designing a good number of important organic transformations leading to the synthesis of biologically relevant compounds at room temperature and pressure. Currently, the concept of green chemistry is globally acclaimed and has already advanced quite significantly to emerge as a distinct branch of chemical sciences. Among the principles of green chemistry, one principle is dedicated to the “design of energy efficiency” – that is, to develop synthetic strategies that require less or the minimum amount of energy to carry out a specific reaction with optimum productivity – and the most effective way to save energy is to develop strategies/protocols that are capable enough to carry out the transformations at ambient temperature! As part of on‐going developments in green synthetic strategies, the design of reactions under ambient conditions coupled with other green aspects is, thus, an area of current interest. The concept of developing reaction strategies at room temperature and pressure is now an emerging field of research in organic chemistry and is progressing steadily. This account is aimed to offer an overview of our recent research works directly related to this particular field of interest, and highlights the green chemistry practice leading to carbon–carbon and carbon–heteroatom bond‐forming reactions of topical significance. Green synthetic routes to a variety of biologically relevant organic molecules (heterocyclic, heteroaromatic, alicyclic, acyclic, etc.) at room temperature and pressure are discussed.

     

Synthesis of highly substituted pyrroles using ultrasound in aqueous media

Abstract

A two-step protocol for the synthesis of highly substituted pyrroles in aqueous media and without catalyst is described. The first step is the dimerization of a 1,3-dicarbonyl compound by ceric ammonium nitrate/ultrasound to produce a tetracarbonyl derivative. This derivative is then combined with an amine in the absence of any catalysts to obtain the pyrrole via a Paal–Knorr reaction. This route is an improvement when compared with classical methodologies toward Green Chemistry objectives.