Wastewater-based epidemiology to assess human exposure to personal care and household products – A review of biomarkers,analytical methods,and applications

Humans are nowadays exposed to numerous chemicals in our day-to-day life, including parabens, UV filters, phosphorous flame retardants/plasticizers, bisphenols, phthalates and alternative plasticizers, which can have different adverse effects to human health. Estimating human’s exposure to these potentially harmful substances is, therefore, of paramount importance. Human biomonitoring (HBM) is the existing approach to assess exposure to environmental contaminants, which relies on the analysis of specific human biomarkers (parent compounds and/or their metabolic products) in biological matrices from individuals. The main drawback is its implementation, which involves complex cohort studies. A novel approach, wastewater-based epidemiology (WBE), involves estimating exposure from the analysis of biomarkers in sewage (a pooled urine and feces sample of an entire population). One of the key challenges of WBE is the selection of biomarkers which are specific to human metabolism, excreted in sufficient amounts, and stable in sewage. So far, literature data on potential biomarkers for estimating exposure to these chemicals are scattered over numerous pharmacokinetic and HBM studies. Hence, this review provides a list of potential biomarkers of exposure to more than 30 widely used chemicals and report on their urinary excretion rates. Furthermore, the potential and challenges of WBE in this particular field is discussed through the review of pioneer WBE studies, which for the first time explored applicability of this novel approach to assess human exposure to environmental contaminants. In the future, WBE could be potentially applied as an “early warning system”, which could promptly identify communities with the highest exposure to environmental contaminants.     

Modification of poly(ethylene terephthalate) fibers,fabrics, and films by amination reactions—A review

Currently, many of our living facilities are dependent on poly(ethylene terephthalate) (PET). It is utilized in the production of textiles, beverage bottles, food packaging, implants, and so forth. Although PET has desirable properties, it has to be amended for certain applications that have been modified by different methods. For modifications, aminolysis is used by several investigators, and this report reviews critically the related literature. Amines can be applied to impart the desired properties and produce active sites to be used for further alterations by successive reactions. Amine treatments alone enhance wettability, increase dyeability, and most applicable, produce functionality on the surface. By further reactions with several other chemicals, a spectrum of properties was endowed to PET products, such as flame retarding, anti-fouling property, highest hygroscopicity, silk-like character, biocompatibility, and so forth. There are a large number of works, mainly to change the surface properties, but the literature on the in vivo or common everyday evaluation of the amended products is scarce. Most of the modifications of PET products by amines are accompanied by a decrease in some other properties. Then the process of aminolysis and modifications have to be optimized with respect to several production parameters.     

A new route to the zizaane sesquiterpenes: An efficient synthesis of (±)-isokhusimone

A novel route to the zizaane sesquiterpene skeleton is demonstrated with a nine-step synthesis of (±)-isokhusimone (2) from norcamphor in an overall yield of 35%. This constitutes a formal synthesis of (±)khusimone (1).     

Inductively coupled plasma – Tandem mass spectrometry (ICP-MS/MS): A powerful and universal tool for the interference-free determination of (ultra)trace elements – A tutorial review

This paper is intended as a tutorial review on the use of inductively coupled plasma – tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H₂, O₂ and NH₃, also the use of promising alternative gases, such as CH₃F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis.     

Poly(ethylene terephthalate) waste derived chemicals as an antistripping additive for bitumen – An environment friendly approach for disposal of environmentally hazardous material

The increasing accumulation of poly(ethylene terephthalate) polymer and poor recycle/disposal practices have made them omnipresent and a major culprit for environmental pollution. Currently global research efforts are focused on primary and secondary recycling of PET waste or through landfills. Chemical recycling of PET through hydrolytic or aminolytic route has been attempted by many researchers however with limited end applications. In our investigations we have used PET waste as a synthon and chemically converted it through a new non-catalytic route into several benzamide derivatives. We have successfully tested them for antistripping performance in bitumen. Our results as elaborated in the paper indicate a comparable performance of the new chemistry products based on PET, to commercially used antistripping chemicals. Our research work thus opens a new route for the recycling of used PET in bituminous concrete roads which may help in alleviating a major environmental problem and disposal of waste PET polymer in large scale.     

Recent progress of poly (N-isopropylacrylamide) hybrid hydrogels: synthesis,fundamentals and applications – review

Hydrogels, having nanomaterials (e.g. nanoparticles and nanorods) incorporated inside their polymeric meshes, are generally called hybrid gels/hydrogels. These assemblies combine the properties of both hydrogels and nanomaterials in one system. These responsive hybrid hydrogels, particularly polymerized N-isopropylacrylamide (PoNip) polymeric gels, have been extensively exploited for various multi-disciplinary applications in the literature over the past two decades because of their unique and exquisite particulars. Next generation assemblies have been prepared by using the smart nature of these gels toward the general incentives (e.g. temperature, ionic strength, and pH) in the fields of nanocatalysis, water purification, drug delivery, photonics, and optics. This review presents an overview of the PoNip hybrid assemblies engineered over the past 7 years i.e. 2010–2016 and extensively discusses the interaction of the incorporated nanomaterial with the polymeric chains of the hydrogels as it is the most significant factor which makes these assemblies attractive for all the associated applications. Moreover, this article also describes the preparative routes, properties, classification, and applications of these hybrid hydrogels in the fields of medicine, environment, catalysis, and nanotechnology.     

An unexpected Pummerer rearrangement in the synthetic route to ethyl (2′-hydroxy-4′,5′-methylenedioxyphenyl)acetate: An alternative approach to 2,3-dimethylthio benzofurans

The synthesis of ethyl (2′-hydroxy-4′,5′-methylendioxophenyl)acetate, a fragment of the antihyperglycemic natural coumarin subcoriacin, is reported. We found an expeditious route to the title compound in five steps. Final metal catalyzed acid ethanolysis of the vinylic 1,1-methylthio methylsulfoxide derivative afforded the required aryl acetic ester, but in the absence of metal catalyst, an unexpected Pummerer rearrangement produced the 2,3-dimethylthiofuran derivative as the major product. This last result provides an alternative entry to 2,3-dimethlythiobenzofurans.     

Microwave Assisted Synthesis of Poly(ether sulfone) – An Efficient Synthetic Route to Control Polymer Chain Structure

A novel synthetic process for the efficient control over molecular weight of the poly(ether sulfone) has been studied. The application of microwave irradiation for the condensation polymerization to synthesize poly(ether sulfone) is demonstrated. Microwave assisted polymerization results in significant reduction of reaction time. Microwave based process is also feasible at lower temperature for the synthesis of poly(ether sulfone). Polymers synthesized have been characterized using NMR and FTIR spectroscopy. Polymer film morphology and surface composition have been studied using SEM and EDX. An increase in the molecular weight is observed with increasing microwave irradiation time.     

An updated review of metal–organic framework materials in photo(electro)catalytic applications: From CO2 reduction to wastewater treatments

This review summarizes recent advances in the development of metal–organic framework (MOF) materials, focusing on their photocatalytic and photoelectrocatalytic activities for different applications, such as CO₂ reduction, water splitting, elimination of inorganic contaminants, and degradation of organic pollutants. In each section, the first applications described focus on the photocatalysts developed using MOF materials. Meanwhile, the latest are centered on photoelectrode applications using these materials. The last advances in the synthesis process are discussed in terms of improvement in electron transfer and charge separation, which enhance the activity of the photo (electro)catalysts. Finally, some insights about the upcoming applications of MOF materials are provided.     

α,n-Didehydrotoluenes by Photoactivation of (Chlorobenzyl)trimethylsilanes: An Alternative to Enyne-Allenes Cyclization

Doubly radical: A novel entry to α,n-didehydrotoluene (DHT) diradicals is disclosed and proceeds through the photochemical activation of (chlorobenzyl)trimethylsilanes with chloride loss and elimination of the SiMe(3) (+) group. The products formed in solution are indicative of the intermediacy of the three isomers of the α,n-DHT.     

An Expedient Approach to the Benzopyran Core: Application to Synthesis of the Natural Products(±)-Xyloketals and(±)-Alboatrin

A mild and efficient protocol for the synthesis of the benzopyran ring has been described and a series of chromans compounds is reported, the yield is from 72% to 95%. The diadduct tended to angular product and showed good regioselectivity. This strategy was applied for the benzopyran derived natural products (±)‐xyloketals and (±)‐alboatrin. The crystal of compound 9 exhibited centro‐symmetric space group, containing two isomers in one unit. The relative configurations were 1R,10R,15S and 34S,22R,30S, respectively.     

An alternate route to the C(7)C(13)subunit of erythronolide B via A hydropyran template

Conversion of (R)-3-benzyloxy-2-methylpropionaldehyde (4) to the erythronolide B C(7)C(13) subunit 13 in 15% overall yield is described. Chelation-controlled carbonyl additions and a dioxanone-to-dihydropyran Claisen rearrangement are key steps.     

Zr(HSO4)4/SiO2: An effective heterogeneous alternative for one-pot synthesis of β-acetamido ketones

In a one-pot procedure, enolizable ketones reacted with aromatic aldehydes, acetyl chloride and acetonitrile at room temperature in the presence of Zr(HSO₄)₄/SiO₂ to furnish the corresponding β-acetamido ketones in improved yields.     

An approach to aliphatic 1,8-stereocontrol: diastereoselective syntheses of (±)-patulolide C and (±)-epipatulolide C

The tin(iv) bromide promoted reaction of 7-hydroxy-7-phenylhept-2-enyl(tributyl)stannane 11 with benzaldehyde gave a mixture of the epimeric 1,8-diphenyloct-3-ene-1,8-diols 12 and so indirect methods were developed for aliphatic 1,8-stereocontrol to complete diastereoselective syntheses of (±)-patulolide C 1 and (±)-epipatulolide C 40. (5Z)-3,7-syn-7-(2-Trimethylsilylethoxy)methoxyocta-1,5-dien-3-ol 17 was prepared from the tin(iv) chloride promoted reaction of 4-(2-trimethylsilylethoxy)methoxypent-2-enyl(tributyl)stannane 16 with acrolein (1,5-syn?:?1,5-anti = 96?:?4). An Ireland-Claisen rearrangement of the corresponding benzoyloxyacetate 21 with in situ esterification of the resulting acid using trimethylsilyldiazomethane gave methyl (4E,7Z)-2,9-anti-2-benzyloxy-9-(2-trimethylsilylethoxy)methoxydeca-4,7-dienoate 22 together with 10-15% of its 2,9-syn-epimer 26, the 2,9-syn-?:?2,9-anti-ratio depending on the conditions used. An 88?:?12 mixture of esters was taken through to the tert-butyldiphenylsilyl ether 38 of (±)-patulolide C 1 together with 6% of its epimer 39, by reduction, a Wittig homologation and deprotection/macrocyclisation. Following separation of the epimeric silyl ethers, deprotection of the major epimer 38 gave (±)-patulolide C 1. The success of 2,3-Wittig rearrangements of allyl ethers prepared from (5Z)-3,7-syn-7-(2-trimethylsilylethoxy)methoxyocta-1,5-dien-3-ol 17 was dependent on the substituents on the allyl ether. Best results were obtained using the pentadienyl ether 56 and the cinnamyl ether 49 that rearranged with >90?:?10 stereoselectivity in favour of (1E,5E,8Z)-3,10-syn-1-phenyl-10-(2-trimethylsilylethoxy)methoxyundeca-1,5,8-trien-3-ol 50. This product was taken through to the separable silyl ethers 38 and 39, ratio 7?:?93 by regioselective epoxidation and alkene reduction using diimide, followed by deoxygenation, ozonolysis, a Wittig homologation and selective deprotection/macrocyclisation. Deprotection of the major epimer 39 gave (±)-epipatulolide C 40.     

A stereoselective approach to the angucyclinone antibiotics: A total synthesis of (±)-urdamycinone B

A stereoselective chiral Lewis acid promoted reaction of siloxydiene (±)-13 and dienophile complex 18, gave a 4:1 mixture of urdamycinone B (1) and its C-3 epimer (24) in several steps in 12% overall yield. Separation of these products was achieved by high performance liquid chromatography (HPLC).     

Glycosidation of 3,4,6-Tri-O-Benzyl-2-Ethenyl-D-Glucal – A Route to 2-C-(β-Methyl)Methylene Glycosides

ABSTRACT

Monosaccharidic and disaccharidic 2-C-(β-methyl)methylene glycosides were synthesized by an electrophilic conjugate addition reaction of ROH-type compounds in the presence of Ph₃P⁺H Br^? to 2-ethenyl-3,4,6-tri-O-benzyl-D-glucal 1, functioning as a model glycosyl donor. This 2-vinyl glucal derivative represents a series of 2-vinyl and 2-butadienyl glycals, prepared by Wittig-type methylenation of pyranosidic conjugated enals, derived from glucal, galactal and lactal. The exo-(β-methyl)methylene group paves the way for further chemical transformations.     

In-chain functionalized poly(ε-caprolactone): A valuable precursor towards the synthesis of 3-miktoarm star containing hyperbranched polyethylene

Well-defined 3-miktoarm star copolymer 3μ-HBPE(PCL)₂ (HBPE: hyperbranched polyethylene, PCL: poly[ε-caprolactone]) was synthesized by combining chain walking polymerization (CWP), ring-opening polymerization (ROP), and “click” chemistry. The synthetic methodology includes the following steps: (a) synthesis of in-chain ethynyl-functionalized PCL, (PCL)₂-C ≡ CH by ROP of ε-caprolactone (CL) with ethylene-functionalized solketal (3-[prop-2-yn-1-yloxy] propane-1,2-diol) as difunctional initiator and phosphazene superbase t-BuP₂ as catalyst; (b) synthesis of azido-functionalized hyperbranched PE (HBPE-N₃) by CWP of ethylene with α-diimine-Pd(II) catalyst, followed by quenching with excess 4-vinylbenzyl chloride and transformation of chloro to azide group with sodium azide; and (c) “clicking” HBPE-N₃ and (PCL)₂-C ≡ CH using copper(I)-catalyzed azide–alkyne cycloaddition. ¹H NMR spectroscopy, gel permeation chromatography, Fourier-transform infrared spectroscopy, and differential scanning calorimetry were used to determine the molecular characteristics and thermal properties of the polymers. Self-assembly behavior of 3μ-HBPE (PCL)₂ in petroleum ether, a selective solvent for HBPE, was investigated by dynamic light scattering, atomic force microscopy, and transmission electron microscopy. The in-chain alkyne-functionalized poly(ε-caprolactone) is a valuable precursor for PCL-based complex macromolecular architectures.     

A theoretical study of the OH-initiated gas-phase oxidation mechanism of β-pinene (C10H16): first generation products

An extensive mechanism for the OH-initiated oxidation of β-pinene up to the first-generation products was derived based on quantum chemical calculations, theoretical kinetics, and structure-activity relationships. The resulting mechanism deviates from earlier explicit mechanisms in several key areas, leading to a different product yield prediction. Under oxidative conditions, the inclusion of ring closure reactions of unsaturated alkoxy radicals brings the predicted nopinone and acetone yields to an agreement with the experimental data. Routes to the formation of other observed products, either speciated or observed as peaks in mass spectrometric studies, are also discussed. In pristine conditions, we predict significant acetone formation following ring closure reactions in alkylperoxy radicals; in addition, we predict some direct OH recycling in subsequent H-migration reactions in alkylperoxy radicals. The uncertainties on the key reactions are discussed. Overall, the OH-initiated oxidation of β-pinene is characterized by the formation of a few main products, and a very large number of products in minor to very small yields.