synthesis

Synthesis, characterization, and crystal structure of hexa­kis­(1-methyl-1H-imidazole-κN3)zinc(II) dinitrate

The synthesis of the title compound, [Zn(C4H6N2)6](NO3)2, is described. This complex consists of a central zinc metal ion surrounded by six 1-methyl­imidazole ligands, charge balanced by two nitrate anions. The complex crystallizes in the space group Poverline{3}. In the crystal, the nitrate ions are situated within the cavities created by the [Zn(N-Melm)6]2+ cations, serving as counter-ions. The three oxygen atoms of the nitrate ion engage in weak C—H⋯O inter­actions. In addition to single-crystal X-ray diffraction analysis, the complex was characterized using elemental analysis, 1H NMR, 13C NMR, and FTIR spectroscopy.




synthesis

Coupling between 2-pyridyl­selenyl chloride and phenyl­seleno­cyanate: synthesis, crystal structure and non-covalent inter­actions

A new pyridine-fused seleno­diazo­lium salt, 3-(phenyl­selan­yl)[1,2,4]selena­diazolo[4,5-a]pyridin-4-ylium chloride di­chloro­methane 0.352-solvate, C12H9N2Se2+·Cl−·0.352CH2Cl2, was obtained from the reaction between 2-pyridyl­selenenyl chloride and phenyl­seleno­cyanate. Single-crystal structural analysis revealed the presence of C—H⋯N, C—H⋯Cl−, C—H⋯Se hydrogen bonds as well as chalcogen–chalcogen (Se⋯Se) and chalcogen–halogen (Se⋯Cl−) inter­actions. Non-covalent inter­actions were explored by DFT calculations followed by topological analysis of the electron density distribution (QTAIM analysis). The structure consists of pairs of seleno­diazo­lium moieties arranged in a head-to-tail fashion surrounding disordered di­chloro­methane mol­ecules. The assemblies are connected by C—H⋯Cl− and C—H⋯N hydrogen bonds, forming layers, which stack along the c-axis direction connected by bifurcated Se⋯Cl−⋯H—C inter­actions.




synthesis

Synthesis, crystal structure and Hirshfeld surface analysis of (2-amino-1-methyl­benzimidazole-κN3)aqua­bis­(4-oxopent-2-en-2-olato-κ2O,O')nickel(II) ethanol monosolvate

The mol­ecule of the title compound, [Ni(C5H7O2)2(C8H9N3)(H2O)]·C2H5OH, has triclinic (Poverline{1}) symmetry. This compound is of inter­est for its anti­microbial properties. The asymmetric unit comprises two independent complex mol­ecules, which are linked by N—H⋯O and O—H⋯O hydrogen bonds along [111]. Hirshfeld surface analysis indicates that 71.7% of inter­mol­ecular inter­actions come from H⋯H contacts, 17.7% from C⋯H/H⋯C contacts and 7.6% from O⋯H/H⋯O contacts, with the remaining contribution coming from N⋯H/H⋯N, C⋯N/N⋯C, C⋯C and O⋯O contacts.




synthesis

Synthesis and crystal structure of poly[ethanol(μ-4-methyl­pyridine N-oxide)di-μ-thio­cyanato-cobalt(II)]

Reaction of 4-methyl­pyridine N-oxide and Co(NCS)2 in ethanol as solvent accidentally leads to the formation of single crystals of Co(NCS)2(4-methyl­pyridine N-oxide)(ethanol) or [Co(NCS)2(C6H7NO)(C2H6O)]n. The asymmetric unit of the title compound consists of one CoII cation, two crystallographically independent thio­cyanate anions, one 4-methyl­pyridine N-oxide coligand and one ethanol mol­ecule on general positions. The cobalt cations are sixfold coordinated by one terminal and two bridging thio­cyanate anions, two bridging 4-methyl­pyridine N-oxide coligands and one ethanol mol­ecule, with a slightly distorted octa­hedral geometry. The cobalt cations are linked by single μ-1,3(N,S)-bridging thio­cyanate anions into corrugated chains, that are further connected into layers by pairs of μ-1,1(O,O)-bridging 4-methyl­pyridine N-oxide coligands. The layers are parallel to the bc plane and are separated by the methyl groups of the 4-methyl­pyridine N-oxide coligands. Within the layers, intra­layer hydrogen bonding is observed.




synthesis

Synthesis, non-spherical structure refinement and Hirshfeld surface analysis of racemic 2,2'-diisobut­oxy-1,1'-bi­naphthalene

In the racemic title compound, C28H30O2, the naphthyl ring systems subtend a dihedral angle of 68.59 (1)° and the mol­ecular conformation is consolidated by a pair of intra­molecular C—H⋯π contacts. The crystal packing features a weak C—H⋯π contact and van der Waals forces. A Hirshfeld surface analysis of the crystal structure reveals that the most significant contributions are from H⋯H (73.2%) and C⋯H/H⋯C (21.2%) contacts.




synthesis

Synthesis and crystal structure of poly[[μ-chlorido-μ-(2,3-di­methyl­pyrazine)-copper(I)] ethanol hemisolvate], which shows a new isomeric CuCl(2,3-di­methyl­pyrazine) network

Reaction of copper(I)chloride with 2,3-di­methyl­pyrazine in ethanol leads to the formation of the title compound, poly[[μ-chlorido-μ-(2,3-di­methyl­pyrazine)-copper(I)] ethanol hemisolvate], {[CuCl(C6H8N2)]·0.5C2H5OH}n or CuCl(2,3-di­methyl­pyrazine) ethanol hemisolvate. Its asymmetric unit consists of two crystallographically independent copper cations, two chloride anions and two 2,3-di­methyl­pyrazine ligands as well as one ethanol solvate mol­ecule in general positions. The ethanol mol­ecule is disordered and was refined using a split model. The methyl H atoms of the 2,3-di­methyl­pyrazine ligands are also disordered and were refined in two orientations rotated by 60° relative to each other. In the crystal structure, each copper cation is tetra­hedrally coordinated by two N atoms of two bridging 2,3-di­methyl­pyrazine ligands and two μ-1,1-bridg­ing chloride anions. Each of the two copper cations are linked by pairs of bridging chloride anions into dinuclear units that are further linked into layers via bridging 2,3-di­methyl­pyrazine coligands. These layers are stacked in such a way that channels are formed in which the disordered solvent mol­ecules are located. The topology of this network is completely different from that observed in the two polymorphic modifications of CuCl(2,3-di­methyl­pyrazine) reported in the literature [Jess & Näther (2006). Inorg. Chem. 45, 7446–7454]. Powder X-ray diffraction measurements reveal that the title compound is unstable and transforms immediately into an unknown crystalline phase.




synthesis

Synthesis, crystal structure and Hirshfeld surface analysis of sulfamethoxazolium methyl­sulfate monohydrate

The mol­ecular salt sulfamethoxazolium {or 4-[(5-methyl-1,2-oxazol-3-yl)sulf­amo­yl]anilinium methyl sulfate monohydrate}, C10H12N3O3S+·CH3O4S−·H2O, was prepared by the reaction of sulfamethoxazole and H2SO4 in methanol and crystallized from methanol–ether–water. Protonation takes place at the nitro­gen atom of the primary amino group. In the crystal, N—H⋯O hydrogen bonds (water and methyl­sulfate anion) and inter­molecular N—H⋯N inter­actions involving the sulfonamide and isoxazole nitro­gen atoms, link the components into a tri-dimensional network, additional cohesion being provided by face-to-face π–π inter­actions between the phenyl rings of adjacent mol­ecules. A Hirshfeld surface analysis was used to verify the contributions of the different inter­molecular inter­actions, showing that the three most important contributions for the crystal packing are from H⋯O (54.1%), H⋯H (29.2%) and H⋯N (5.0%) inter­actions.




synthesis

Synthesis and crystal structure of 1H-1,2,4-triazole-3,5-di­amine monohydrate

The title compound, a hydrate of 3,5-di­amino-1,2,4-triazole (DATA), C2H5N5·H2O, was synthesized in the presence of sodium perchlorate. The evaporation of H2O from its aqueous solution resulted in anhydrous DATA, suggesting that sodium perchlorate was required to precipitate the DATA hydrate. The DATA hydrate crystallizes in the P21/c space group in the form of needle-shaped crystals with one DATA and one water mol­ecule in the asymmetric unit. The water mol­ecules form a three-dimensional network in the crystal structure. Hirshfeld surface analysis revealed that 8.5% of the inter­molecular inter­actions originate from H⋯O contacts derived from the incorporation of the water mol­ecules.




synthesis

Synthesis, crystal structure and properties of μ-tetra­thio­anti­monato-bis­[(cyclam)zinc(II)] perchlorate 0.8-hydrate

The reaction of Zn(ClO4)2·6H2O with Na3SbS4·9H2O in a water/aceto­nitrile mixture leads to the formation of the title compound, (μ-tetra­thio­anti­monato-κ2S:S')bis­[(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ4N)zinc(II)] perchlorate 0.8-hydrate, [Zn2(SbS4)(C10H24N4)2]ClO4·0.8H2O or [(Zn-cyclam)2(SbS4)]+[ClO4]−·0.8H2O. The asymmetric unit consists of two crystallographically independent [SbS4]3– anions, two independent perchlorate anions and two independent water mol­ecules as well as four crystallographically independent Zn(cyclam)2+ cations that are located in general positions. Both perchlorate anions and one cyclam ligand are disordered and were refined with a split mode using restraints. The water mol­ecules are partially occupied. Two Zn(cyclam)2+ cations are linked via the [SbS4]3– anions into [Zn2(cyclam)2SbS4]+ cations that are charged-balanced by the [ClO4]− anions. The water mol­ecules of crystallization are hydrogen bonded to the [SbS4]3– anions. The cations, anions and water mol­ecules are linked by N—H⋯O, N—H⋯S and O—H⋯S hydrogen bonds into a three-dimensional network. Powder X-ray diffraction proves that a pure sample had been obtained that was additionally investigated for its spectroscopic properties.




synthesis

Synthesis, structures and Hirshfeld surface analyses of 2-hy­droxy-N'-methyl­acetohydrazide and 2-hy­droxy-N-methyl­acetohydrazide

The structures of the title compounds 2-hy­droxy-N'-methyl­acetohydrazide, 1, and 2-hy­droxy-N-methyl­acetohydrazide, 2, both C3H8N2O2, as regioisomers differ in the position of the methyl group relative to the N atoms in 2-hy­droxy-acetohydrazide. In the structure of 1, the 2-hy­droxy-acetohydrazide core [OH—C—C(=O)—NH—NH] is almost planar and the methyl group is rotated relative to this plane. As opposed to 1, in the structure of 2 all non-hydrogen atoms lie in the same plane. The hydroxyl and carbonyl groups in structures 1 and 2 are in trans and cis positions, respectively. The methyl amino group and carbonyl group are in the cis position relative to the C—N bond in structure 1, while the amino group and carbonyl group are in the trans position relative to the C—N bond in stucture 2. In the crystal, mol­ecules of 1 are linked by N—H⋯O and O—H⋯N inter­molecular hydrogen bonds, forming layers parallel to the ab crystallographic plane. A Hirshfeld surface analysis showed that the H⋯H contacts dominate the crystal packing with a contribution of 55.3%. The contribution of the H⋯O/O⋯H inter­action is somewhat smaller, amounting to 30.8%. In the crystal, as a result of the inter­molecular O—H⋯O hydrogen bonds, mol­ecules of 2 form dimers, which are linked by N—H⋯O hydrogen bonds and a three-dimensional supra­molecular network The major contributors to the Hirshfeld surface are H⋯H (58.5%) and H⋯O/O⋯H contacts (31.7%).




synthesis

Synthesis and crystal structure of sodium (ethane-1,2-di­yl)bis­[(3-meth­oxy­prop­yl)phosphinodi­thiol­ate] octa­hydrate

The title compound, catena-poly[[tri­aqua­sodium]-di-μ-aqua-[tri­aqua­sodium]-μ-(ethane-1,2-di­yl)bis­[(3-meth­oxy­prop­yl)phosphinodi­thiol­ato]], [Na2(C10H22O2P2S4)(H2O)8]n, crystallizes in the triclinic space group P1. The dianionic [CH3O(CH2)3P(=S)(S—)CH2CH2P(=S)(S—)(CH2)3OCH3]2− ligand fragments are joined by a dicationic [Na2(H2O)8]2+ cluster that includes the oxygen of the meth­oxy­propyl unit of the ligand to form infinite chains.




synthesis

Synthesis, crystal structure and absolute configuration of (3aS,4R,5S,7aR)-7-(but-3-en-1-yn-1-yl)-2,2-dimethyl-3a,4,5,7a-tetra­hydro-2H-1,3-benzodioxole-4,5-diol

The absolute configuration of the title compound, C13H16O4, determined as 1S,2R,3S,4R based on the synthetic pathway, was confirmed by single-crystal X-ray diffraction. The mol­ecule is a relevant inter­mediary for the synthesis of speciosins, ep­oxy­quinoides or their analogues. The mol­ecule contains fused five- and six-membered rings with two free hydroxyl groups and two protected as an iso­propyl­idenedioxo ring. The packing is directed by hydrogen bonds that define double planes of mol­ecules laying along the ab plane and van der Waals inter­actions between aliphatic chains that point outwards of the planes.




synthesis

Synthesis and crystal structure of 1,3,5-tris­[(1H-benzotriazol-1-yl)meth­yl]-2,4,6-tri­ethyl­benzene

In the crystal structure of the title compound, C33H33N9, the tripodal mol­ecule exists in a conformation in which the substituents attached to the central arene ring are arranged in an alternating order above and below the ring plane. The three benzotriazolyl moieties are inclined at angles of 88.3 (1), 85.7 (1) and 82.1 (1)° with respect to the mean plane of the benzene ring. In the crystal, only weak mol­ecular cross-linking involving C—H⋯N hydrogen bonds is observed.




synthesis

Synthesis and structure of trans-2,5-di­methyl­piperazine-1,4-diium di­hydrogen diphosphate

In the title salt, C6H16N22+ ·H2P2O72−, the complete dication is generated by a crystallographic centre of symmetry with the methyl groups in equatorial orientations. The complete dianion is generated by a crystallographic twofold axis with the central O atom lying on the axis: the P—O—P bond angle is 135.50 (12)°. In the crystal, the di­hydrogen diphosphate anions are linked by O—H⋯O hydrogen bonds, generating (001) layers. The organic cations bond to the inorganic layers by way of N—H⋯O and C—H⋯O hydrogen bonds. A Hirshfeld surface analysis shows that the most important contributions for the crystal packing are from O⋯H/H⋯O (60.5%) and H⋯H (39.4%) contacts.




synthesis

Synthesis, crystal structure and Hirshfeld surface analysis of 2-{4-[(2-chloro­phen­yl)meth­yl]-3-methyl-6-oxopyridazin-1-yl}-N-phenyl­acetamide

In the title mol­ecule, C20H18ClN3O2, the 2-chloro­phenyl group is disordered to a small extent [occupancies 0.875 (2)/0.125 (2)]. The phenyl­acetamide moiety is nearly planar due to a weak, intra­molecular C—H⋯O hydrogen bond. In the crystal, N—H⋯O hydrogen bonds and π-stacking inter­actions between pyridazine and phenyl rings form helical chains of mol­ecules in the b-axis direction, which are linked by C—H⋯O hydrogen bonds and C—H⋯π(ring) inter­actions. A Hirshfeld surface analysis was performed, which showed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O inter­actions to dominate the inter­molecular contacts in the crystal.




synthesis

Crystal structure and Hirshfeld surface analysis of the salt 2-iodo­ethyl­ammonium iodide – a possible side product upon synthesis of hybrid perovskites

The title organic–inorganic hybrid salt, C2H7IN+·I−, is isotypic with its bromine analog, C2H7BrN+·Br− [Semenikhin et al. (2024). Acta Cryst. E80, 738–741]. Its asymmetric unit consists of one 2-iodo­ethyl­ammonium cation and one iodide anion. The NH3+ group of the organic cation forms weak hydrogen bonds with four neighboring iodide anions, leading to the formation of supra­molecular layers propagating parallel to the bc plane. Hirshfeld surface analysis reveals that the most important contribution to the crystal packing is from N—H⋯I inter­actions (63.8%). The crystal under investigation was twinned by a 180° rotation around [001].




synthesis

Synthesis and structure of penta­kis­(2-aminopyridinium) nona­vanado(V)tellurate(VI)

In the title compound, (C5H7N2)5[TeV9O28], the tellurium and vanadium atoms are statistically disordered over two of the ten metal-atom sites in the [TeV9O28]5– heteropolyanion. The anions stack along [100] and are extended into a three-dimensional supra­molecular network through N—H⋯O and weak C—H⋯O hydrogen bonds involving the self-assembled 2-amino­pyridinium penta­mers, which are linked by C—H⋯π and π–π stacking inter­actions. The most important contributions to the Hirshfeld surface arise from O⋯H/H⋯O (54.8%), H⋯H (17.8%) and C⋯H/H⋯C (13.4%) contacts.




synthesis

Synthesis and in-depth structure determination of a novel metastable high-pressure CrTe3 phase

This study reports the synthesis and crystal structure determination of a novel CrTe3 phase using various experimental and theoretical methods. The average stoichiometry and local phase separation of this quenched high-pressure phase were characterized by ex situ synchrotron powder X-ray diffraction and total scattering. Several structural models were obtained using simulated annealing, but all suffered from an imperfect Rietveld refinement, especially at higher diffraction angles. Finally, a novel stoichiometrically correct crystal structure model was proposed on the basis of electron diffraction data and refined against powder diffraction data using the Rietveld method. Scanning electron microscopy–energy-dispersive X-ray spectrometry (EDX) measurements verified the targeted 1:3 (Cr:Te) average stoichiometry for the starting compound and for the quenched high-pressure phase within experimental errors. Scanning transmission electron microscopy (STEM)–EDX was used to examine minute variations of the Cr-to-Te ratio at the nanoscale. Precession electron diffraction (PED) experiments were applied for the nanoscale structure analysis of the quenched high-pressure phase. The proposed monoclinic model from PED experiments provided an improved fit to the X-ray patterns, especially after introducing atomic anisotropic displacement parameters and partial occupancy of Cr atoms. Atomic resolution STEM and simulations were conducted to identify variations in the Cr-atom site-occupancy factor. No significant variations were observed experimentally for several zone axes. The magnetic properties of the novel CrTe3 phase were investigated through temperature- and field-dependent magnetization measurements. In order to understand these properties, auxiliary theoretical investigations have been performed by first-principles electronic structure calculations and Monte Carlo simulations. The obtained results allow the observed magnetization behavior to be interpreted as the consequence of competition between the applied magnetic field and the Cr–Cr exchange interactions, leading to a decrease of the magnetization towards T = 0 K typical for antiferromagnetic systems, as well as a field-induced enhanced magnetization around the critical temperature due to the high magnetic susceptibility in this region.




synthesis

A new science synthesis for public land management of the effects of noise from oil and gas development on raptors and songbirds

The USGS is working with federal land management agencies to develop a series of structured science syntheses (SSS) to support National Environmental Policy Act (NEPA) analyses. This new synthesis is the third publication in the SSS series and provides science to support NEPA analyses for agency decisions regarding oil and gas leasing and permitting.




synthesis

Powell Center Proposals: How to develop successful synthesis proposals

Dr. Jill Baron, Director of the Powell Center, will present a webinar on how to develop a strong proposal for Working Group on November 19th, 2024, at 11am MT/1pm ET.




synthesis

Tapping the unused potential of photosynthesis

Scientists from the University of Southampton have reengineered the fundamental process of photosynthesis to power useful chemical reactions that could be used to produce biofuels, pharmaceuticals and fine chemicals.

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  • Physics & Chemistry

synthesis

How Does Photosynthesis Work?

Photosynthesis has fueled life on Earth for billions of years. Learn how it shapes ecosystems, sustains life, and even aids climate models.




synthesis

Quinoxalines Synthesis, Reactions, Mechanisms and Structure

Location: Electronic Resource- 




synthesis

Organic Chemistry from Retrosynthesis to Asymmetric Synthesis

Location: Electronic Resource- 




synthesis

Electroacoustic Piano Concert via Modular Synthesis

The last time I performed a series of electroacoustic piano pieces was November of 2016 (click the link for an audio example). However, I am always imagining interesting ways that the piano, one of the most ancient of all synthesizers … Continue reading




synthesis

Reply to Sysel et al.: Comment on the importance of using nitric oxide gas in the synthesis of nitrosylcobalamin and ICH-validated methods to assess purity and stability [Letters to the Editor]

In their comment (1) on our publication (2), the authors make two points: (i) they raise concerns about the possible effect of residual NONOate in our study, and (ii) they promote nitrosylcobalamin (NOCbl) supplied by their own company. Both points lack merit for the following reasons. The authors make the astonishing claim that the spectra of nitric oxide (NO•) and cobalamins overlap. Unlike NO•, cobalamin absorbs in the visible region, permitting unequivocal spectral assignment of NOCbl as reported (3). We demonstrated that whereas NOCbl is highly unstable in solution, it is stabilized by the B12 trafficking protein CblC. So even if present, residual NONOate (which is unstable at neutral pH and is removed during the work-up (3)) could not account for the observed difference.The authors then misrepresent our synthetic method, claiming that anaerobic conditions were used to generate nitrocobalamin (NO2Cbl), which results in the transient formation of NOCbl. We synthesized NO2Cbl aerobically using nitrite as described (4); NOCbl is not an intermediate in this ligand exchange reaction. The aerobic instability of NOCbl has been rigorously described by inorganic chemists (3, 5) and raises obvious questions about its purported biological effects as exemplified by the authors' own 2003 JBC publication, which was later withdrawn.As to promoting NOCbl from their company, the authors refer to a synthetic route from a mixture of NO• gas and aquocobalamin. The authors' method (6) has been described as “dubious” by chemists (5). Whereas DEAE NONOate used in our method is widely known as an NO• donor,...




synthesis

Comment on the importance of using nitric oxide gas in the synthesis of nitrosylcobalamin and ICH-validated methods to assess purity and stability [Letters to the Editor]

After a thorough read of this paper (1), we wish to clarify that the authors' anaerobic method of synthesis for the production of nitrocobalamin results in the transient formation of nitrosylcobalamin, an unstable intermediate upon exposure to air. We concur that the authors' method results in the production of nitrocobalamin based on the UV-visible data as shown. The authors' adapted anaerobic method consists of mixing hydroxocobalamin hydrochloride with diethylamine NONOate diethylammonium salt in aqueous solution. Of concern, the UV spectrum of nitric oxide overlaps that of all cobalamin species under anaerobic conditions, making any assignments of the binding of nitric oxide to hydroxocobalamin suspect (2). Additionally, the use of acetone to precipitate the authors' product causes precipitation of diethylamine NONOate, resulting in an impure product. As a result, its utility for drawing experimental conclusions is faulty.The product from the authors' anaerobic synthetic method has not been assessed for purity, and the synthetic method itself has not been validated using a stability-indicating method as required by the International Conference on Harmonization (ICH) (ICH Q2B, Validation of Analytical Procedures) methodology, which is a hallmark for analytical characterization. Our nitrosylcobalamin synthesis involves reacting nitric oxide gas with hydroxocobalamin acetate as a heterogeneous mixture in a non-electron-donating solvent followed by rotary evaporation. Our nitrosylcobalamin product is stable in air, releases nitric oxide gas in situ (3), and meets ICH stability guidelines (4). Additionally, our nitrosylcobalamin product demonstrates biological activity, which has not been observed for nitrocobalamin (3, 5).




synthesis

Biosynthesis of the sactipeptide Ruminococcin C by the human microbiome: Mechanistic insights into thioether bond formation by radical SAM enzymes [Microbiology]

Despite its major importance in human health, the metabolic potential of the human gut microbiota is still poorly understood. We have recently shown that biosynthesis of Ruminococcin C (RumC), a novel ribosomally synthesized and posttranslationally modified peptide (RiPP) produced by the commensal bacterium Ruminococcus gnavus, requires two radical SAM enzymes (RumMC1 and RumMC2) catalyzing the formation of four Cα-thioether bridges. These bridges, which are essential for RumC's antibiotic properties against human pathogens such as Clostridium perfringens, define two hairpin domains giving this sactipeptide (sulfur-to-α-carbon thioether–containing peptide) an unusual architecture among natural products. We report here the biochemical and spectroscopic characterizations of RumMC2. EPR spectroscopy and mutagenesis data support that RumMC2 is a member of the large family of SPASM domain radical SAM enzymes characterized by the presence of three [4Fe-4S] clusters. We also demonstrate that this enzyme initiates its reaction by Cα H-atom abstraction and is able to catalyze the formation of nonnatural thioether bonds in engineered peptide substrates. Unexpectedly, our data support the formation of a ketoimine rather than an α,β-dehydro-amino acid intermediate during Cα-thioether bridge LC–MS/MS fragmentation. Finally, we explored the roles of the leader peptide and of the RiPP precursor peptide recognition element, present in myriad RiPP-modifying enzymes. Collectively, our data support a more complex role for the peptide recognition element and the core peptide for the installation of posttranslational modifications in RiPPs than previously anticipated and suggest a possible reaction intermediate for thioether bond formation.




synthesis

Marked reduction in bile acid synthesis in cholesterol 7{alpha}-hydroxylase-deficient mice does not lead to diminished tissue cholesterol turnover or to hypercholesterolemia

Margrit Schwarz
Sep 1, 1998; 39:1833-1843
Articles




synthesis

Multivalent feedback regulation of HMG CoA reductase, a control mechanism coordinating isoprenoid synthesis and cell growth

MS Brown
Jul 1, 1980; 21:505-517
Reviews




synthesis

Thematic Review Series: Glycerolipids. DGAT enzymes and triacylglycerol biosynthesis

Chi-Liang Eric Yen
Nov 1, 2008; 49:2283-2301
Thematic Reviews




synthesis

Genetic diseases of the Kennedy pathways for membrane synthesis [Molecular Bases of Disease]

The two branches of the Kennedy pathways (CDP-choline and CDP-ethanolamine) are the predominant pathways responsible for the synthesis of the most abundant phospholipids, phosphatidylcholine and phosphatidylethanolamine, respectively, in mammalian membranes. Recently, hereditary diseases associated with single gene mutations in the Kennedy pathways have been identified. Interestingly, genetic diseases within the same pathway vary greatly, ranging from muscular dystrophy to spastic paraplegia to a childhood blinding disorder to bone deformations. Indeed, different point mutations in the same gene (PCYT1; CCTα) result in at least three distinct diseases. In this review, we will summarize and review the genetic diseases associated with mutations in genes of the Kennedy pathway for phospholipid synthesis. These single-gene disorders provide insight, indeed direct genotype-phenotype relationships, into the biological functions of specific enzymes of the Kennedy pathway. We discuss potential mechanisms of how mutations within the same pathway can cause disparate disease.




synthesis

Role of phospholipid synthesis in the development and differentiation of malaria parasites in the blood [Microbiology]

The life cycle of malaria parasites in both their mammalian host and mosquito vector consists of multiple developmental stages that ensure proper replication and progeny survival. The transition between these stages is fueled by nutrients scavenged from the host and fed into specialized metabolic pathways of the parasite. One such pathway is used by Plasmodium falciparum, which causes the most severe form of human malaria, to synthesize its major phospholipids, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. Much is known about the enzymes involved in the synthesis of these phospholipids, and recent advances in genetic engineering, single-cell RNA-Seq analyses, and drug screening have provided new perspectives on the importance of some of these enzymes in parasite development and sexual differentiation and have identified targets for the development of new antimalarial drugs. This Minireview focuses on two phospholipid biosynthesis enzymes of P. falciparum that catalyze phosphoethanolamine transmethylation (PfPMT) and phosphatidylserine decarboxylation (PfPSD) during the blood stages of the parasite. We also discuss our current understanding of the biochemical, structural, and biological functions of these enzymes and highlight efforts to use them as antimalarial drug targets.




synthesis

Methylarginine metabolites are associated with attenuated muscle protein synthesis in cancer-associated muscle wasting [Protein Synthesis and Degradation]

Cancer cachexia is characterized by reductions in peripheral lean muscle mass. Prior studies have primarily focused on increased protein breakdown as the driver of cancer-associated muscle wasting. Therapeutic interventions targeting catabolic pathways have, however, largely failed to preserve muscle mass in cachexia, suggesting that other mechanisms might be involved. In pursuit of novel pathways, we used untargeted metabolomics to search for metabolite signatures that may be linked with muscle atrophy. We injected 7-week–old C57/BL6 mice with LLC1 tumor cells or vehicle. After 21 days, tumor-bearing mice exhibited reduced body and muscle mass and impaired grip strength compared with controls, which was accompanied by lower synthesis rates of mixed muscle protein and the myofibrillar and sarcoplasmic muscle fractions. Reductions in protein synthesis were accompanied by mitochondrial enlargement and reduced coupling efficiency in tumor-bearing mice. To generate mechanistic insights into impaired protein synthesis, we performed untargeted metabolomic analyses of plasma and muscle and found increased concentrations of two methylarginines, asymmetric dimethylarginine (ADMA) and NG-monomethyl-l-arginine, in tumor-bearing mice compared with control mice. Compared with healthy controls, human cancer patients were also found to have higher levels of ADMA in the skeletal muscle. Treatment of C2C12 myotubes with ADMA impaired protein synthesis and reduced mitochondrial protein quality. These results suggest that increased levels of ADMA and mitochondrial changes may contribute to impaired muscle protein synthesis in cancer cachexia and could point to novel therapeutic targets by which to mitigate cancer cachexia.




synthesis

Interleukin 6 reduces allopregnanolone synthesis in the brain and contributes to age-related cognitive decline in mice [Research Articles]

Cognitive decline with age is a harmful process that can reduce quality of life. Multiple factors have been established to contribute to cognitive decline, but the overall etiology remains unknown. Here, we hypothesized that cognitive dysfunction is mediated, in part, by increased levels of inflammatory cytokines that alter allopregnanolone (AlloP) levels, an important neurosteroid in the brain. We assessed the levels and regulation of AlloP and the effects of AlloP supplementation on cognitive function in 4-month-old and 24-month-old male C57BL/6 mice. With age, the expression of enzymes involved in the AlloP synthetic pathway was decreased and corticosterone (CORT) synthesis increased. Supplementation of AlloP improved cognitive function. Interestingly, interleukin 6 (IL-6) infusion in young animals significantly reduced the production of AlloP compared with controls. It is notable that inhibition of IL-6 with its natural inhibitor, soluble membrane glycoprotein 130, significantly improved spatial memory in aged mice. These findings were supported by in vitro experiments in primary murine astrocyte cultures, indicating that IL-6 decreases production of AlloP and increases CORT levels. Our results indicate that age-related increases in IL-6 levels reduce progesterone substrate availability, resulting in a decline in AlloP levels and an increase in CORT. Furthermore, our results indicate that AlloP is a critical link between inflammatory cytokines and the age-related decline in cognitive function.




synthesis

Lipid sensing tips the balance for a key cholesterol synthesis enzyme [Images in Lipid Research]




synthesis

Design, Synthesis, and Preclinical Evaluation of a High-Affinity 18F-Labeled Radioligand for Myocardial Growth Hormone Secretagogue Receptor Before and After Myocardial Infarction

The peptide hormone ghrelin is produced in cardiomyocytes and acts through the myocardial growth hormone secretagogue receptor (GHSR) to promote cardiomyocyte survival. Administration of ghrelin may have therapeutic effects on post–myocardial infarction (MI) outcomes. Therefore, there is a need to develop molecular imaging probes that can track the dynamics of GHSR in health and disease to better predict the effectiveness of ghrelin-based therapeutics. We designed a high-affinity GHSR ligand labeled with 18F for imaging by PET and characterized its in vivo properties in a canine model of MI. Methods: We rationally designed and radiolabeled with 18F a quinazolinone derivative ([18F]LCE470) with subnanomolar binding affinity to GHSR. We determined the sensitivity and in vivo and ex vivo specificity of [18F]LCE470 in a canine model of surgically induced MI using PET/MRI, which allowed for anatomic localization of tracer uptake and simultaneous determination of global cardiac function. Uptake of [18F]LCE470 was determined by time–activity curve and SUV analysis in 3 regions of the left ventricle—area of infarct, territory served by the left circumflex coronary artery, and remote myocardium—over a period of 1.5 y. Changes in cardiac perfusion were tracked by [13N]NH3 PET. Results: The receptor binding affinity of LCE470 was measured at 0.33 nM, the highest known receptor binding affinity for a radiolabeled GHSR ligand. In vivo blocking studies in healthy hounds and ex vivo blocking studies in myocardial tissue showed the specificity of [18F]LCE470, and sensitivity was demonstrated by a positive correlation between tracer uptake and GHSR abundance. Post-MI changes in [18F]LCE470 uptake occurred independently of perfusion tracer distributions and changes in global cardiac function. We found that the regional distribution of [18F]LCE470 within the left ventricle diverged significantly within 1 d after MI and remained that way throughout the 1.5-y duration of the study. Conclusion: [18F]LCE470 is a high-affinity PET tracer that can detect changes in the regional distribution of myocardial GHSR after MI. In vivo PET molecular imaging of the global dynamics of GHSR may lead to improved GHSR-based therapeutics in the treatment of post-MI remodeling.




synthesis

Mitochondria Divide Roles for Energy and Molecular Synthesis Under Low-Nutrient Conditions, Reveals New Study

New findings reveal that mitochondria in nutrient-deprived cells adopt specialised roles to prioritise either energy generation or amino acid synthesis. Led by Dr. Craig Thompson of Memorial Sloan Kettering Cancer Center, the study identified specific mitochondrial subpopulations, allowing cells to maintain critical functions even under stress. These discoveries have implications for understanding how cancer cells survive low-nutrient conditions and how cells repair after injury.




synthesis

Scientists Move Closer to Synthesising Element 120, Marking Potential New Era in Periodic Table

Scientists at Lawrence Berkeley National Laboratory in California are exploring new techniques for creating superheavy elements, focusing on the potential synthesis of “element 120,” also called unbinilium. If successful, this addition could lead to an eighth row on the periodic table. Using ion bombardment, researchers demonstrated a process that may achieve unbinilium by targeting californium with supercharged titanium ions. The approach offers promise, although creating just two atoms could take weeks. This project marks an important step forward in understanding atomic structures and superheavy elements.




synthesis

removing cdn_loop_breaker from the genus synthesis netlist

I am trying to remove the cdn_loop_breaker cells from the netlist. 
When I tried the below 2 things, genus synthesis tool removing the cdn_loop_breaker cells but while connecting the cdn_loop_breaker cell input to its proper connection, its somehow misleading the connections

Things i tried:
1.  remove_cdn_loop_breaker -instances *cdn_loop_breaker*
then i just ran remove_cdn_loop_breaker  comand without the -instances switch
2. remove_cdn_loop_breaker  
     
both of the above things are not providing the proper connections after removing the loop_breaker_cells

can anyone suggest the best possible workaround for this please?




synthesis

Training Bytes: Explore Cadence DFT Synthesis Flow with Bytes

Training Bytes are not just short technical videos; they are particularly designed to provide comprehensive support in understanding and learning various concepts and methodologies.

These comprehensive yet small Training Bytes can be created to show various concepts and processes in a shorter pane of five to ten minutes, for example, running DFT synthesis, scanning insertion, inserting advanced testability features, test point insertion, debugging DFT violations, etc.

In this blog, we will show you the DFT Synthesis Flow with Cadence's Genus Synthesis Solution using small Training Bytes available on the Cadence Learning and Support Portal. To explore these training bytes more, log on to support.cadence.com and select the learning section to choose the training videos, as shown below.

DFT Synthesis Flow with Genus Synthesis Solution

First, we will understand the Synthesis Flow with DFT in the Genus Synthesis Solution:

Understanding a Script File that Used to Run the Synthesis Flow With DFT

Here, we will show you "How to run the Test Synthesis Flow to Insert Scan Chains and Improve the Testability of a Design" in the Genus Synthesis Solution:

Running Test Synthesis Flow to Insert Scan Chains And Improve the Testability of a Design in the Genus Synthesis Solution

Let's check the flops marked with the dft_mapped attribute for scan mapping in Genus Synthesis Solution:

How to Check Flops Marked With dft_mapped Attribute For Scan Mapping in Genus Synthesis Solution?

How to Find Non-Scan Flops of a Design in Genus? (Video)

Once the flops are mapped to scan flip flops and the scan chain inserted, we will see how to handle the flops marked with the dft_dont_scan attribute for scan mapping in Genus Synthesis Solution.

How to Handle the Flops Marked With the dft_dont_scan Attribute For Scan Mapping in Genus Synthesis Solution?

Here, we will see how to fix DFT Violations using the command fix_dft_violations:

Fixing DFT Violations (Video)

Once the design has been synthesized, let's explore the DFT design hierarchy in Genus Stylus CUI:

Exploring DFT Design Hierarchy in Genus Stylus CUI (Video)

Understand why sequential elements are not mapped to a scan flop:

Why Are Sequential Elements Not Mapped to a Scan Flop?

Explore hierarchical scan synthesis in Genus Stylus Common UI:

Understanding Hierarchical Scan Synthesis in Genus Stylus Common UI. (Video)

To understand how to resolve different warnings and errors (for example, DFT-415, DFT-512, DFT-304, etc.) in Genus Synthesis Solution, here are some videos you can refer to:

How to Resolve Warning: DFT-415 (Video)

How to Resolve Error: DFT-407 (Video)

How to Resolve Error: DFT-404 (Video)

DFT-510 Warning During Mapping (Video)

How to Resolve Warning: DFT-512 (Video)

How to Resolve Warning: DFT-511 (Video)

How to Resolve Warning: DFT-304 (Video)

How to Resolve Warning: DFT-302 (Video)

How to Resolve Error: DFT-515 (Video)

How to Resolve Error: DFT-500 (Video)

Here, we will see how we can generate SDC constraints for DFT constructs for many scan insertion techniques, such as FULLSCAN, OPCG, Boundary Scan, PMBIST, XOR Compression, SmartScan Compression, LBIST, and IEEE 1500:

How to Generate SDC Constraints for DFT Constructs in Genus Synthesis Solution? (Video)

Explore advanced testability features that can be inserted in Genus Synthesis Solution, such as Boundary Scan, Programmable Memory built-in Self-Test Logic (PMBIST), Compression Logic, Masking, and On-Product Clock Generation Logic (OPCG):

Advanced Testability Features (Video)

To understand What the IEEE 1500 Wrapper and its Insertion Flow in Genus Synthesis Solution, follow the bytes:

What Is IEEE 1500 Wrapper? (Video)

IEEE 1500 Wrapper Insertion Flow in Genus Synthesis Solution (Video)

Understand the On-product Clock Generation (OPCG) insertion flow in Genus Synthesis Solution Stylus CUI with this byte:

Understanding On Product Clock Generator (OPCG) Insertion in Genus Stylus CUI (Video)

To debug DFT violations, you can use DFT Analyzer from Genus GUI and explore its features here:

Debugging Using GUI: DFT Analyzer (Video)

Exploring DFT Analyzer View of Genus Synthesis Solution GUI (Video)

To understand What is Shadow Logic, How to Insert Test Points, How to do Testability Analysis Using LBIST, and How to Deterministic Fault Analysis in Genus, follow this article:

What is Shadow Logic

To insert the Boundary Scan Logic in and control Boundary Optimization in Genus Synthesis Solution, refer to these small bytes:

How to Insert Boundary Scan Logic in Genus? Video)

Controlling Boundary Optimization in Genus Synthesis Solution Stylus CUI (Video)

Compression techniques are used during scan insertion to reduce the test data volume and test application time (TAT) while retaining the test coverage. To understand what compression and the compression techniques are, watch this article:

What is Compression Technique During Scan Insertion? (Video)

Interested to know what "Unified Compression" is? To get the concept, you can watch this small demo:

What Is Unified Compression? (Video)

To Explore More, Register for Online Training




synthesis

to write a synthesis paper step by step

to write a synthesis paper step by step




synthesis

to write synthesis paper

to write synthesis paper




synthesis

Antenatal Care Interventions to Increase Contraceptive Use Following Birth in Low- and Middle-Income Countries: Systematic Review and Narrative Synthesis

ABSTRACTIntroduction:Health risks associated with short interpregnancy intervals, coupled with women’s desires to avoid pregnancy following childbirth, underscore the need for effective postpartum family planning programs. The antenatal period provides an opportunity to intervene; however, evidence is limited on the effectiveness of interventions aimed at reaching women in the antenatal period to increase voluntary postpartum family planning in low- and middle-income countries (LMICs). This systematic review aimed to identify and describe interventions in LMICs that attempted to increase postpartum contraceptive use via contacts with pregnant women in the antenatal period.Methods:Studies published from January 2012 to July 2022 were considered if they were conducted in LMICs, evaluated an intervention delivered during the antenatal period, were designed to affect postpartum contraceptive use, were experimental or quasi-experimental, and were published in French or English. The main outcome of interest was postpartum contraceptive use within 1 year after birth, defined as the use of any method of contraception at the time of data collection. We searched EMBASE, Global Health, and Medline and manually searched the reference lists from studies included in the full-text screening.Results:We double-screened 771 records and included 34 reports on 31 unique interventions in the review. Twenty-three studies were published from 2018 on, with 21 studies conducted in sub-Saharan Africa. Approximately half of the study designs (n=16) were randomized controlled trials, and half (n=15) were quasi-experimental. Interventions were heterogeneous. Among the 24 studies that reported on the main outcome of interest, 18 reported a positive intervention effect, with intervention recipients having greater contraceptive use in the first year postpartum.Conclusion:While the studies in this systematic review were heterogeneous, the findings suggest that interventions that included a multifaceted package of initiatives appeared to be most likely to have a positive effect.




synthesis

WAV2VGM Plays Audio Via OPL3 Synthesis

Once upon a time, computers didn’t really have enough resources to play back high-quality audio. It took too much RAM and too many CPU cycles and it was just altogether …read more




synthesis

MIT's Novel Method for Plant Based Drug Synthesis

MIT chemists have devised a novel method for synthesizing complex compounds that were initially extracted from plants and have the potential as medlinkantibiotics/medlink,




synthesis

Re-evaluating retrosynthesis algorithms with Syntheseus

Faraday Discuss., 2024, Advance Article
DOI: 10.1039/D4FD00093E, Paper
Krzysztof Maziarz, Austin Tripp, Guoqing Liu, Megan Stanley, Shufang Xie, Piotr Gaiński, Philipp Seidl, Marwin H. S. Segler
Syntheseus provides reference models and search algorithms as well as metrics to evaluate and improve synthesis planning tools.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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synthesis

ZnIn2S4 nanosheets with tunable dual vacancies for efficient sacrificial-agent-free H2O2 photosynthesis

Inorg. Chem. Front., 2024, Advance Article
DOI: 10.1039/D4QI02030H, Research Article
Chen Zhang, Gao Xu, Qifeng Liang, Li Liang, Zebo Fang, Rong Wu, Shunhang Wei, Lei Wang, Xiaoxiang Xu
ZnIn2S4 nanosheets with tunable concentration of dual vacancies were prepared. Introducing dual vacancies effectively promotes photocarrier separation, facilitates O2 adsorption, and inhibits H2O2 decomposition by increasing hydrophilicity.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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synthesis

Synthesis and structure of chlororuthenacyclopentatriene

Inorg. Chem. Front., 2024, Advance Article
DOI: 10.1039/D4QI01833H, Research Article
Zhenwei Chu, Zhishun Peng, Xu Cheng, Yuhui Hua, Guomei He, Jiangxi Chen, Guochen Jia
Chlororuthenacyclopentatriene, representing a new member of the ruthenaaromatic family, was successfully prepared using the reactions of RuCl2(PPh3)3 with o-phenyldiyne derivatives in the presence of excess HCl.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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synthesis

Fe3O4-decorated MXene for the effective removal of 133Ba and 137Cs: synthesis, characterization, and optimization via response surface methodology (RSM)

Inorg. Chem. Front., 2024, 11,7860-7871
DOI: 10.1039/D4QI00404C, Research Article
Shalu Atri, Vipul Vilas Kusumkar, Süleyman İnan, Maros Gregor, Tomas Roch, Maria Caplovicova, Michal Galambos, Eva Viglasova, Gustav Plesch, Martin Motola, Olivier Monfort
The potential activity of Fe3O4 decorated MXenes in the removal of highly toxic 133Ba and 137Cs using a radioactive indicator method.
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