Alternative Synthesis Research Articles

5-Hydroxymethyl Furfural Oxidation by Perylene Diimide-Sensitized Electrodes Boosted by Photoinduced Doping.

We explored the electrochemical behavior of antimony-doped tin oxide (ATO) and perylene diimide (PDI)-sensitized ATO (ATO-PDI) for the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) mediated conversion of 5-hydroxymethyl furfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a value-added substrate for alternative polymer synthesis. We first showed that ATO displayed good electrocatalytic properties towards TEMPO, affording a quasi-reversible response with a heterogeneous rate constant on the order of 2×10-4 cm s-1. We then evaluated the performance of ATO under exhaustive electrolysis of HMF in basic aqueous electrolyte, reaching 80 % Faradaic Efficiency (FE) for FDCA production. Interestingly, a significantly enhanced current (up to 2.5 mA cm-2) was recorded over time when ATO-PDI was exposed to prolonged visible illumination in a Dye-Sensitized Photoelectrochemical Cell (DSPEC) configuration, which we ascribed to the photoinduced doping of ATO resulting from the oxidative quenching of PDI excited states. The proposed system enabled the production of FDCA with ca. 75 % FE in <2 h reaction time, and an almost quantitative HMF conversion when both the mono- and di-acid products were considered. To the best of our knowledge, this is the first example of a molecular dye-sensitized interface used for the TEMPO-mediated oxidation of HMF.

Impact of ERG6 Gene Deletion on Membrane Composition and Properties in the Pathogenic Yeast Candida glabrata.

The ERG6 gene is crucial for the biosynthesis of ergosterol, a key component of yeast cell membranes. Our study examines the impact of ERG6 gene deletion on the membrane composition and physicochemical properties of the pathogenic yeast Candida glabrata. Specifically, we investigated changes in selected sterol content, phospholipid composition, transmembrane potential, and PDR16 gene activity. Sterol levels were measured using high-performance liquid chromatography, the phospholipid profile was analysed via thin-layer chromatography, transmembrane potential was assessed with fluorescence spectroscopy, and gene expression levels were determined by quantitative PCR. Our findings revealed a depletion of ergosterol, increased zymosterol and eburicol content, an increased phosphatidylcholine and a reduced phosphatidylethanolamine content in the Δerg6 strain compared to the wt. Additionally, the Δerg6 strain exhibited membrane hyperpolarization without changes in PDR16 expression. Furthermore, the Δerg6 strain showed increased sensitivity to the antifungals myriocin and aureobasidine A. These results suggest that ERG6 gene deletion leads to significant alterations in membrane composition and may activates an alternative ergosterol synthesis pathway in the C. glabrata Δerg6 deletion mutant.

Comparative Transcriptome Analysis of Non-Organogenic and Organogenic Tissues of Gaillardia pulchella Revealing Genes Regulating De Novo Shoot Organogenesis

Gaillardia pulchella is an important plant species with pharmacological and ornamental applications. It contains a wide array of phytocompounds which play roles against diseases. In vitro propagation requires callogenesis and differentiation of plant organs, which offers a sustainable, alternative synthesis of compounds. The morphogenetic processes and the underlying mechanisms are, however, known to be under genetic regulation and are little understood. The present study investigated these events by generating transcriptome data, with de novo assembly of sequences to describe shoot morphogenesis molecularly in G. pulchella. The RNA was extracted from the callus of pre- and post-shoot organogenesis time. The callus induction was optimal using leaf segments cultured onto MS medium containing α-naphthalene acetic acid (NAA; 2.0 mg/L) and 6-benzylaminopurine (BAP; 0.5 mg/L) and further exhibited a high shoot regeneration/caulogenesis ability. A total of 68,366 coding sequences were obtained using Illumina150bpPE sequencing and transcriptome assembly. Differences in gene expression patterns were noted in the studied samples, showing opposite morphogenetic responses. Out of 10,108 genes, 5374 (53%) were downregulated, and there were 4734 upregulated genes, representing 47% of the total genes. Through the heatmap, the top 100 up- and downregulating genes’ names were identified and presented. The up- and downregulated genes were identified using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Important pathways, operative during G. pulchella shoot organogenesis, were signal transduction (13.55%), carbohydrate metabolism (8.68%), amino acid metabolism (5.11%), lipid metabolism (3.75%), and energy metabolism (3.39%). The synthesized proteins displayed phosphorylation, defense response, translation, regulation of DNA-templated transcription, carbohydrate metabolic processes, and methylation activities. The genes’ product also exhibited ATP binding, DNA binding, metal ion binding, protein serine/threonine kinase -, ATP hydrolysis activity, RNA binding, protein kinase, heme and GTP binding, and DNA binding transcription factor activity. The most abundant proteins were located in the membrane, nucleus, cytoplasm, ribosome, ribonucleoprotein complex, chloroplast, endoplasmic reticulum membrane, mitochondrion, nucleosome, Golgi membrane, and other organellar membranes. These findings provide information for the concept of molecular triggers, regulating programming, differentiation and reprogramming of cells, and their uses.

A base-promoted synthesis of 3,4-dihydro-2(1H)-quinazolinones

Abstract A convenient and concise base-promoted synthesis of 3,4-dihydro-2(1H)-quinazolinones and multi-membered cyclic ureas has been developed. In the presence of tBuOK, a variety of 3,4-dihydro-2(1H)-quinazolinones as well as the N-arylated five-, six- and nine-membered cyclic ureas were readily synthesized under mild conditions. This method offers an alternative synthesis toolkit towards cyclic ureas.

A Broad Spectrum Lasso Peptide Antibiotic Targeting the Bacterial Ribosome.

Lasso peptides, biologically active molecules with a distinct structurally constrained knotted fold, are natural products belonging to the class of ribosomally-synthesized and posttranslationally modified peptides (RiPPs). Lasso peptides act upon several bacterial targets, but none have been reported to inhibit the ribosome, one of the main antibiotic targets in the bacterial cell. Here, we report the identification and characterization of the lasso peptide antibiotic, lariocidin (LAR), and its internally cyclized derivative, lariocidin B (LAR-B), produced by Paenabacillussp. M2, with broad-spectrum activity against many bacterial pathogens. We show that lariocidins inhibit bacterial growth by binding to the ribosome and interfering with protein synthesis. Structural, genetic, and biochemical data show that lariocidins bind at a unique site in the small ribosomal subunit, where they interact with the 16S rRNA and aminoacyl-tRNA, inhibiting translocation and inducing miscoding. LAR is unaffected by common resistance mechanisms, has a low propensity for generating spontaneous resistance, shows no human cell toxicity, and has potent in vivo activity in a mouse model of Acinetobacter baumannii infection. Our finding of the first ribosome-targeting lasso peptides uncovers new routes toward discovering alternative protein synthesis inhibitors and offers a new chemical scaffold for developing much-needed antibacterial drugs.

Abstract C042: Identification of a non-canonical pathway used by CAF to deliver gamma-aminobutyric acid in pancreatic cancer

Abstract Cancer-associated fibroblasts (CAFs) are cells responsible for deposition and remodeling of the extracellular matrix, and modification of the stromal microenvironment, which facilitates tumor growth. Moreover, CAFs are extremely immunosuppressive because they produce large amounts of inhibitory cytokines, growth factors and metabolites. Thus, understanding how CAFs impart severe immunosuppression in the tumor microenvironment is critical to make PDAC amenable to immunotherapies. The link between metabolism and immunosuppression in tumors has become clearer in recent years, and we postulate that one such metabolite, gamma-aminobutyric acid (GABA), a key inhibitory neurotransmitter, can act as a major immunosuppressive metabolite in PDAC. Our preliminary data shows that CAFs produce high levels of glutamate (Glu) and that metabolites derived from glutamate, such as GABA, are immunosuppressive to NK cells. Moreover, we found that CAFs could produce GABA, de novo, as determined by heavy isotope tracing. Thus, our goal is to uncover the mechanisms used by CAFs to produce GABA, and to evaluate the immunosuppressive mechanisms behind CAF- derived GABA. GABA production was measured in the conditioned media of CAFs grown in 3D culture, where it was observed that inhibition of glutaminase (GLS) and glutamine synthetase (GS) enzymes was not able to decrease the GABA levels. In addition, CAFs did not express glutamate decarboxylase (GAD), the canonical enzyme responsible for the conversion of Glu to GABA, which led us to explore the expression of a non-canonical GABA synthesis pathways in CAFs. Intriguingly, we found that CAFs derived from patient tumors expressed the enzymes of non-canonical pathway (ODC1, DAO, ALDH1A1 and ALDH9A1), and to a greater degree when compared to normal fibroblasts isolated from donor pancreata (Gift of Life Program). CRISPRi mediated knockdown (KD) of aldehyde dehydrogenase 1 (ALDH1a1) in CAFs decreased GABA production compared to control CAFs. On the other hand, CAFs knocked down for diamine oxidase (DAO), showed increased GABA production, suggesting a compensatory mechanism for GABA production upstream of ALDH1a1. Overall, our preliminary data demonstrate that CAFs produce GABA de novo, via a putative alternative GABA synthesis pathway. Our next steps are to identify the cytokine profile of KDs CAFs and perform functional assays utilizing our 3D co-culturing system, uncovering natural killer cell responses to tumor cells in the presence of CAFs with and without the enzymes necessary for GABA production. Translationally, we are analyzing the tumor interstitial fluid from PDAC patients to uncover metabolites/cytokines (secreted factors) that can be correlated with patient parameters (ex. overall survival) and immune cell activation and functionality. It is our hope that the insight provided by this study can lead to a novel set of prognostic or diagnostic factors to improve clinical outcomes in this devasting disease. Citation Format: Ariana Musa de Aquino, Myree Graves, Farrah Ali Ali, David A. Rangel, Langley Kyra, Julie Clark, David Kwon, Guillaume Cognet, Alex Muir, Débora Barbosa Vendramini Costa, Ralph Francescone. Identification of a non-canonical pathway used by CAF to deliver gamma-aminobutyric acid in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C042.

Alternative lipid synthesis in response to phosphate limitation promotes antibiotic tolerance in Gram-negative ESKAPE pathogens.

Gram-negative ESKAPE pathogens, including A cinetobacter baumannii , are responsible for a dramatic increase in the morbidity and mortality of patients in healthcare settings over the past two decades. Infections are difficult to treat due to antibiotic resistance and tolerance; however, broadly conserved mechanisms that promote antibiotic treatment failure have not been extensively studied. Herein, we identify an alternative lipid biosynthesis pathway that is induced in phosphate starvation that enables Gram-negative ESKAPE pathogens, including A. baumannii , Klebsiella pneumoniae , and Enterobacter cloacae to build lipid bilayers in the absence of glycerophospholipids, which are the canonical bilayers lipid. Replacement of the anionic phosphate in the lipid headgroup with zwitterionic ornithine and lysine promote survival against colistin, a last resort antimicrobial used against Gram-negative infections. These studies suggest that ESKAPE pathogens can remodel their bilayers with phosphate free lipids to overcome colistin treatment and that aminolipid biosynthesis could be targeted to improve antimicrobial treatment.

An Ultramicroporous Zinc‐Based Zeolitic Imidazolate Framework‐8 for the Adsorption of CO2, CH4, CO, N2 and H2: A Combined Experimental and Theoretical Study

AbstractAn alternative synthesis route to obtain ultramicroporous zeolitic imidazolate framework‐8 (ZIF‐8) is reported that is rapid and does not require organic solvent or heating. The polyethylene glycol‐templated ZIF‐8 nanoparticles (&lt;50 nm size) exhibited a high BET (Brunauer, Emmett and Teller) surface area of 1853 m2/g, a total pore volume of 0.73 cm3/g, and 0.54 nm ultramicropores. A new approach is introduced here to better understand gas adsorption in porous metal organic frameworks (MOFs) that combines theoretical and experimental isotherm data obtained for five gases with statistical physics modelling. The multiscale analytical model reveals that the gas molecules, irrespective of their structure, adsorb in a mixed orientation at low temperature, and a parallel multi‐molecular orientation at higher temperature. The number of gas molecules adsorbed per site ranged from 0.83–2.2 while the number of adsorbent layers ranged between 1.4–5.6, depending on the gas and the temperature. The multilayer adsorption processes involved adsorption energies from 2.85 kJ/mol–9.77 kJ/mol for all gases, consistent with physisorption via van der Waals and London dispersion forces. The initial adsorption energies were higher and therefore stronger. A particularly high capacity for CO2 of 1088 mg(CO2)/g at 298 K was observed while H2 adsorption was only 9 mg(H2)/g. The other gases adsorbed at 145 mg/g–245 mg/g at 298 K. Thermodynamic functions that governed the adsorption process such as the internal energy, the enthalpy, and Gibbs free energy, are also reported, as well as the adsorption entropies, for the 5 gases.

An alternative and scalable synthesis for Relugolix

An alternative and efficient synthetic route for Relugolix was accomplished by changing the construction order of three main parts A, B and C. After the optimization, its scale-up of the preparation for Relogulix was completed in a seven-step methodology with overall yield of 61 % and 99.62 % HPLC purity.

Short communication: An alternative pathway for melatonin synthesis in the skin of European flounder (Platichthys flesus)

The classic melatonin biosynthesis pathway (Mel; N-acetyl-5-methoxytryptamine) involves two consecutive enzymatic steps that are decisive in hormone production: conversion of serotonin (5-hydroxytryptamine; 5-HT) to N-acetylserotonin (NAS) and the methylation of the last compound to Mel. This pathway requires the activity of the enzymes: the first is of the category of N-acetyltransferases (AANAT, SNAT, or NAT) and the second is N-acetylserotonin O-methyltransferase (ASMT; also known as HIOMT). However, quite recently, new information has been provided on the possibility of an alternative Mel synthesis pathway; it would include a two-step action by these enzymes, but in reverse order, where ASMT (or ASMTL, the enzyme related to ASMT) methylates 5-HT to 5-methoxytryptamine (5-MT), and then the last compound is acetylated by an enzyme of the category of N-acetyltransferases to Mel. In our study on the activity of enzymes in the Mel biosynthesis pathway in flounder skin, we have found an increase in 5-MT level, as a result of the increase in 5-HT concentration, which is followed by a growing concentration of Mel. However, we have not found any increase in Mel concentration, despite an increase in NAS in the samples. Our data strongly suggest an alternative way of Mel production in flounder skin in which 5-HT is first methylated to 5-MT, which is then acetylated to Mel.

A Novel Approach to Continuous and Scalable Synthesis of Cation-Disordered Rocksalt Cathodes

Cation disordered rocksalts (DRX) are an emerging class of high energy density LIB cathodes that can utilize earth-abundant and low-cost redox active transition metals. The DRX cathodes can be synthesized through a rich chemistry of transition metals, where commonly, metal-oxide precursors are combined with lithium source via ball-milling and calcined to achieve cation disordered phase. In this work, we present a new alternative synthesis method to the traditional solid-state synthesis, which provides scalable and continuous production of cathode precursors. A soft synthesis method in aqueous media was adopted to produce Mn-rich cathode precursors in large scale, through which homogenous mixing of the introduced transition metal cations was achieved. Here we report the electrochemical and structural properties of as-synthesized DRX cathodes with various Mn-compositions.

Mechanistic Insights on the Formation of a Carbodiimide Ion from Urea in La2O2NCN Synthesis Based on the "Proanion" Strategy.

This study affords mechanistic insights into the formation mechanism of carbodiimide ions (NCN2-) from urea during the synthesis of La2O2NCN by employing the "proanion" strategy without using NH3 gas. It is a safer, cost-effective, and environmentally friendly approach. Urea, acting as a proanion, decomposes upon heating, facilitating conversion to NCN2-. This work meticulously examines the phase transitions and identifies intermediate species formed during the reaction using in situ X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric-differential thermal analysis-mass spectrometry. The findings present a detailed mechanism in which urea initially decomposes at 140 °C, releasing HNCO, which reacts with La(OH)3 to immobilize NCO- species on the surface of La(OH)3. As the temperature reaches approximately 400 °C, these NCO- anions transform into NCN2- anions by releasing CO2 gas, resulting in the formation of an amorphous phase rich in NCN2-. Following further heating to 600 °C, La2O2NCN crystallizes, enhancing its crystallinity as the temperature increases. These findings elucidate the formation mechanism of La2O2NCN, introduce the "proanion method" for the alternative synthesis of metal (oxy)carbodiimides, and expand their potential for applications as functional materials.

A Study on a Compact Double Layer Sub-GHz Reflectarray Design Suitable for Wireless Power Transfer

The paper presents a novel small-footprint varactor diode-based reconfigurable reflectarray (RRA) design and investigates its power reflection efficiency theoretically and experimentally in a real-life indoor environment. The surface is designed to operate at 865.5 MHz and is intended for simultaneous use with other wireless power transfer (WPT) efficiency-improving techniques that have been recently reported in the literature. To the best of the authors’ knowledge, no RRA intended to improve the performance of antenna-based WPT systems operating in the sub-GHz range has been designed and studied both theoretically and experimentally so far. The proposed RRA is a two-layer structure. The top layer contains electronically tunable phase shifters for the local phase control of an incoming electromagnetic wave, while the other one is fully covered by metal to reduce the phase shifter size and RRA’s backscattering. Each phase shifter is a pair of diode-loaded 8-shaped metallic patches. Extensive numerical studies are conducted to ascertain a suitable set of RRA unit cell parameters that ensure both adequate phase agility and reflection uniformity for a given varactor parameter. The RRA design parameter finding procedure followed in this paper comprises several steps. First, the phase and amplitude responses of a virtual infinite double periodic RRA are computed using full-wave solver Ansys HFSS. Once the design parameters are found for a given set of physical constraints, the phase curve of the corresponding finite array is retrieved to estimate the side lobe level due to the finiteness of the RRA aperture. Then, a diode reactance combination is found for several different RRA reflection angles, and the corresponding RRA radiation pattern is computed. The numerical results show that the side lobe level and the deviation of the peak reflected power angles from the desired ones are more sensitive to the reflection coefficient magnitude uniformity than to the phase agility. Furthermore, it is found that for scanning angles less than 50°, satisfactory reflection efficiency can be achieved by using the classical reactance profile synthesis approach employing the generalized geometrical optics (GGO) approximation, which is in accord with the findings of other studies. Additionally, for large reflection angles, an alternative synthesis approach relying on the Floquet mode amplitude optimization is utilized to verify the maximum achievable efficiency of the proposed RRA at large angles. A prototype consisting of 36 elements is fabricated and measured to verify the proposed reflectarray design experimentally. The initial diode voltage combination is found by applying the GGO-based phase profile synthesis method to the experimentally obtained phase curve. Then, the voltage combination is optimized in real time based on power measurement. Finally, the radiation pattern of the prototype is acquired using a pair of identical 4-director printed Yagi antennas with a gain of 9.17 dBi and compared with the simulated. The calculated results are consistent with the measured ones. However, some discrepancies attributed to the adverse effects of biasing lines are observed.

Efficient, Facile, and Green Synthesis of Ruthenium Carboxylate Complexes by Manual Grinding

Recently, scientists have been developing sustainable processes, and in this context, mechanochemistry is commonly associated with green chemistry for its ability to reduce waste generation from chemical reactions. The well-known acetate complex, diacetate bis(triphenylphosphine) ruthenium(II) [Ru(OAc)2(PPh3)2], is a versatile precursor for preparing active complexes for several catalytic reactions. This report presents an efficient and straightforward manual grinding protocol for the sustainable synthesis of ruthenium carboxylate complexes starting from the commercially available [RuCl2(PPh3)3] and metal carboxylates. This work represents a novel and preliminary investigation into carboxylate precursors’ alternative solventless synthesis route based on manual grinding. To our knowledge, this is the first time [Ru(OAc)2(PPh3)2] has been prepared via a mechanochemical procedure. The synthesis method has also been investigated for other alkali metal carboxylates and yields ranging from 30 to 80% were obtained. A comparison of sustainability and environmental impact between conventional solution synthesis and the grinding route has been carried out using the E-factor and Mass Productivity. While for the acetate complex E-factor and MP were only slightly better compared with the solvent method (3 vs. 4 for E-factor and ~6 vs. 5 for MP), for benzoate higher results were found (1 vs. ~4 for E-factor and 10 vs. 5 for MP).

The Synthesis of 1,3,4-Thiadiazoles, 1,3,4-Selenadiazoles and Pyrazolo[3,4-d]pyrimidine Derivatives: Utility of hydrazonoyl bromide and DFT study

1,3,4-Selenadiazoles and 1,3,4-thiadiazolese, were synthesized from the reaction of hydrazonoyl bromide with potassium thiocyanate and potassium selenocyanate, respectively. Also, treatment of hydrazonoyl bromide with malononitrile gave pyrazole-4-carbonitrile derivatives which reacted with formic acid, and formamide to produce the respective pyrazolo[3,4-d]pyrimidines. Elemental analyses, alternative synthesis procedures, and spectrum data were used to confirm the structures of the novel compounds. We studied the 1,3-dipolar cycloaddition reaction mechanism of these reactions using the density functional theory (DFT) method at the B3LYP/6–311++G** level of theory. The product formation was explained experimentally by calculations involving natural bond orbitals (NBO) and frontier molecular orbitals (FMO).The results of this study are consistent with the proposed experimental mechanism.

Synthesis and Properties of Hydrophilic and Hydrophobic Deep Eutectic Solvents via Heating-Stirring and Ultrasound.

Deep eutectic solvents (DESs) have emerged as a greener alternative to other more polluting traditional solvents and have attracted a lot of interest in the last two decades. The DESs are less toxic dissolvents and have a lower environmental footprint. This paper presents an alternative synthesis method to the classical heating-stirring method. The ultrasound method is one of the most promising synthesis methods for DESs in terms of yield and energy efficiency. Therefore, the ultrasound synthesis method was studied to obtain hydrophobic (Aliquat 336:L-Menthol (3:7); Lidocaine:Decanoic acid (1:2)) and hydrophilic DESs based on choline chloride, urea, ethylene glycol and oxalic acid. The physical characterization of DESs via comparison of Fourier transform infrared (FTIR) spectra showed no difference between the DESs obtained by heating-stirring and ultrasound synthesis methods. The study and comparison of all the prepared DESs were carried out via nuclear magnetic resonance spectroscopy (NMR). The density and viscosity properties of DESs were evaluated. The density values were similar for both synthesis methods. However, differences in viscosity values were detected due to the presence of some water in hygroscopic DESs.

Tethered Alkylidenes for REMP from Carbon Disulfide Cleavage.

Reactions between tungsten alkylidyne [tBuOCO]W≡CtBu(THF)2 1 and sulfur containing small molecules are reported. Complex 1 reacts with CS2 to produce intermediate η2 bound CS2 complex [O2C(tBuC═)W(η2-(S,C)-CS2)(THF)] 8. Heating complex 8 provides a mixture of a monomeric tungsten sulfido complex 9 and a dimeric complex 10 in a 4:1 ratio, respectively. Heating the mixture does not perturb the ratio. Addition of excess THF in a solution of 9 and 10 (4:1) converts 10 to 9 (>96%) with concomitant loss of (CS)x. Both 9 and 10 can be selectively crystallized from the mixture. An alternative synthesis of exclusively monomeric 9 involves the reaction between 1 and PhNCS. Demonstrating ring expansion metathesis polymerization (REMP), tethered tungsten alkylidene 8 polymerizes norbornene to produce cis-selective syndiotactic cyclic polynorbornene (c-poly(NBE)).

Improving the genetic stability of bacterial growth control for long-term bioproduction.

Using microorganisms for bioproduction requires the reorientation of metabolic fluxes from biomass synthesis to the production of compounds of interest. We previously engineered a synthetic growth switch in Escherichia coli based on inducible expression of theβ- and β'-subunits of RNA polymerase. Depending on the level of induction, the cells stop growing or grow at a rate close to that of the wild-type strain. This strategy has been successful in transforming growth-arrested bacteria into biofactories with a high production yield, releasing cellular resources from growth towards biosynthesis. However, high selection pressure is placed on a growth-arrested population, favoring mutations that allow cells to escape from growth control. Accordingly, we made the design of the growth switch more robust by building in genetic redundancy. More specifically, we added the rpoA gene, encoding for the α-subunit of RNA polymerase, under the control of a copy of the same inducible promoter used for expression control of ββ'. The improved growth switch is much more stable (escape frequency <10-9), while preserving the capacity to improve production yields. Moreover, after a long period of growth inhibition the population can be regenerated within a few generations. This opens up the possibility to alternate biomass accumulation and product synthesis over a longer period of time and is an additional step towards the dynamical control of bioproduction.

Alternative Metallic Fillers for the Preparation of Conductive Nanoinks for Sustainable Electronics

AbstractThe development of electronics with net zero carbon emissions through more efficient and environmentally friendly materials and processes is still a challenge. Here, alternative chemical synthesis routes of metal conductive nanoparticles, based on biodegradable materials are explored, such as nickel, iron–nickel alloy and iron nanoparticles, to be used, in the long term, as fillers in inks for inject printing. Thus, Ni and FeNi metal nanoparticles of 25–12 nm, forming aggregates of 614–574 nm, respectively, are synthesized in water in the presence of a polyol and a reducing agent and under microwave heating that enables a more uniform and fast heating. Iron nanoparticles of 120 ± 40 nm are synthesized in polyol that limits the aggregation and the oxidation degree. Commercial metal nanoparticles of iron and nickel, are coated with ethylene glycol and used for comparison. The conductivity of nanoparticles when pressed into pellets remains similar for both commercial and synthesized samples. However, when deposited on a strip line and heated, synthesized Ni, FeNi, and Fe nanoparticles show significant conductivity and interesting magnetic properties. It is demonstrated that the nanosize facilitates sintering at reduced temperatures and the capping agents prevent oxidation, resulting in promising conductive fillers for printed electronic applications.

An alternative total synthesis of Greensporone C

A simple and efficient stereo selective synthesis of 14-membered Benzannulated macrolactone, Greensporone C has been accomplished in 6.2% overall yield from inexpensive and commercially available starting materials. This convergent synthesis employs Sharpless asymmetric dihydroxylation, Wittig olefination and Yamaguchi macrolactonization as the key steps.