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Proceedings of the Japan Academy.... 2021Metal-catalyzed asymmetric synthesis is one of the most important methods for the economical and environmentally benign production of useful optically active compounds.... (Review)
Review
Metal-catalyzed asymmetric synthesis is one of the most important methods for the economical and environmentally benign production of useful optically active compounds. The success of the asymmetric transformations is significantly dependent on the structure and electronic properties of the chiral ligands coordinating to the center metals, and hence the development of highly efficient ligands, especially chiral phosphine ligands, has long been an important research subject in this field. This review article describes the synthesis and applications of P-chiral phosphine ligands possessing chiral centers at the phosphorus atoms. Rationally designed P-chiral phosphine ligands are synthesized by the use of phosphine-boranes as the intermediates. Conformationally rigid and electron-rich P-chiral phosphine ligands exhibit excellent enantioselectivity and high catalytic activity in various transition-metal-catalyzed asymmetric reactions. Recent mechanistic studies of rhodium-catalyzed asymmetric hydrogenation are also described.
Topics: Hydrogenation; Ligands; Phosphines; Rhodium
PubMed: 34759073
DOI: 10.2183/pjab.97.026 -
Journal of the American Chemical Society Sep 2022Template-directed synthesis of nucleic acids in the polymerase chain reaction is based on the use of a primer, which is elongated in the replication process. The...
Template-directed synthesis of nucleic acids in the polymerase chain reaction is based on the use of a primer, which is elongated in the replication process. The attachment of a high affinity primer to the end of a template chain has been implemented for templating the synthesis of triazole oligomers. A covalent ester base-pair was used to attach a primer to a mixed sequence template. The resulting primed template has phenol recognition units on the template, which can form noncovalent base-pairs with phosphine oxide monomers via H-bonding, and an alkyne group on the primer, which can react with the azide group on a phosphine oxide monomer. Competition reactions between azides bearing phosphine oxide and phenol recognition groups were used to demonstrate a substantial template effect, due to H-bonding interactions between the phenols on the template and phosphine oxides on the azide. The largest rate acceleration was observed when a phosphine oxide 2-mer was used, because this compound binds to the template with a higher affinity than compounds that can only make one H-bond. The P NMR spectrum of the product duplex shows that the H-bonds responsible for the template effect are present in the product, and this result indicates that the covalent ester base-pairs and noncovalent H-bonded base-pairs developed here are geometrically compatible. Following the templated reaction, it is possible to regenerate the template and liberate the copy strand by hydrolysis of the ester base-pair used to attach the primer, thus completing a formal replication cycle.
Topics: Alkynes; Azides; Esters; Nucleic Acids; Oxides; Phenol; Phosphines; Templates, Genetic; Triazoles
PubMed: 36082527
DOI: 10.1021/jacs.2c08119 -
International Journal of Molecular... May 2021Phosphinate pseudopeptide are analogs of peptides containing phosphinate moiety in a place of the amide bond. Due to this, the organophosphorus fragment resembles the...
Phosphinate pseudopeptide are analogs of peptides containing phosphinate moiety in a place of the amide bond. Due to this, the organophosphorus fragment resembles the tetrahedral transition state of the amide bond hydrolysis. Additionally, it is also capable of coordinating metal ions, for example, zinc or magnesium ions. These two properties of phosphinate pseudopeptides make them an ideal candidate for metal-related protease inhibitors. This research investigates the influence of additional residue in the P2 position on the inhibitory properties of phosphinopeptides. The synthetic strategy is proposed, based on retrosynthetic analysis. The N-C-P bond formation in the desired compounds is conveniently available from the three-component condensation of appropriate amino components, aldehydes, and hypophosphorous acid. One of the crucial synthetic steps is the careful selection of the protecting groups for all the functionals. Determination of the inhibitor activity of the obtained compounds has been done using UV-Vis spectroscopy and standard substrate -Leu--nitroanilide toward the enzymes isolated from the porcine kidney (SsLAP, Leucine aminopeptidase) and barley seeds (HvLAP, Leucine aminopeptidase). An efficient procedure for the preparation of phosphinotripeptides has been performed. Activity test shown that introduction of additional residue into P2 position obtains the micromolar range inhibitors of SsLAP and HvLAP. Moreover, careful selection of the residue in the P2 position should improve its selectivity toward mammalian and plant leucyl aminopeptidases.
Topics: Animals; Enzyme Inhibitors; Leucyl Aminopeptidase; Models, Molecular; Peptide Fragments; Phosphines; Protein Conformation; Swine
PubMed: 34065004
DOI: 10.3390/ijms22105090 -
The Journal of Organic Chemistry Feb 2007This paper describes a phosphine-free palladium-catalyzed method for direct C-arylation of free (N-H)-indoles and pyrroles with iodo- and bromoarene donors. Employing...
This paper describes a phosphine-free palladium-catalyzed method for direct C-arylation of free (N-H)-indoles and pyrroles with iodo- and bromoarene donors. Employing commercially available materials, this new and operationally simple procedure provides a rapid entry to a wide range of C-arylated (N-H)-indoles including derivatives of tryptamine. In the course of this study, a profound halide effect was uncovered, affecting both the efficiency and regioselectivity of indole arylation.
Topics: Catalysis; Indoles; Molecular Structure; Palladium; Phosphines; Pyrroles
PubMed: 17288392
DOI: 10.1021/jo061979v -
Chembiochem : a European Journal of... Sep 2022The synthesis, characterisation, and evaluation of the in vitro cytotoxicity of five maleonitriledithiolate-based ruthenium metal complexes bearing various phosphine...
The synthesis, characterisation, and evaluation of the in vitro cytotoxicity of five maleonitriledithiolate-based ruthenium metal complexes bearing various phosphine ligands towards two ovarian cancer cell lines (A2780 and A2780cisR), one non-small-cell lung cancer cell line (H460) and one normal prostate cell line (PNT2) are presented herein. These 18-electron complexes were designed with four water-soluble phosphine ligands to increase the water-solubility character of the corresponding electron-deficient ruthenium complex which showed great in vitro promises, and triphenylphosphine for comparison. The complexes with triphenylphosphine-3,3',3''-trisulfonic acid and triphenylphosphine present similar cytotoxicity compared to the 16-electron precursor, with equal cytotoxicity to both A2780 and A2780cisR. Hints at the mechanism of action suggest an apoptotic pathway based on reactive oxygen species (ROS) production. No toxicity was observed in preliminary in vivo pilot studies for these two complexes in subcutaneous A2780 and A2780cisR xenograft models, with some evidence of tumour growth delay.
Topics: Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Coordination Complexes; Drug Screening Assays, Antitumor; Female; Humans; Ligands; Lung Neoplasms; Organophosphorus Compounds; Ovarian Neoplasms; Phosphines; Reactive Oxygen Species; Ruthenium; Water
PubMed: 35838006
DOI: 10.1002/cbic.202200259 -
Angewandte Chemie (International Ed. in... Mar 2018We describe a selective and mild chemical approach for controlling RNA hybridization, folding, and enzyme interactions. Reaction of RNAs in aqueous buffer with an...
We describe a selective and mild chemical approach for controlling RNA hybridization, folding, and enzyme interactions. Reaction of RNAs in aqueous buffer with an azide-substituted acylating agent (100-200 mm) yields several 2'-OH acylations per RNA strand in as little as 10 min. This poly-acylated ("cloaked") RNA is strongly blocked from hybridization with complementary nucleic acids, from cleavage by RNA-processing enzymes, and from folding into active aptamer structures. Importantly, treatment with a water-soluble phosphine triggers a Staudinger reduction of the azide groups, resulting in spontaneous loss of acyl groups ("uncloaking"). This fully restores RNA folding and biochemical activity.
Topics: Acylation; Azides; Molecular Structure; Phosphines; RNA; RNA Folding
PubMed: 29370460
DOI: 10.1002/anie.201708696 -
Scientific Reports Feb 2021Phosphine is the most commonly used gas for fumigation for durable commodities globally, but there is still inadequate information regarding its efficacy in conjunction...
Phosphine is the most commonly used gas for fumigation for durable commodities globally, but there is still inadequate information regarding its efficacy in conjunction with proper concentration monitoring. In a series of bioassays, insect mortality after specific exposure intervals to phosphine in selected species was examined, as well as the appearance of the so called "sweet spot". The species that were tested were: Oryzaephilus surinamensis (L.), Tribolium castaneum (Herbst), Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) with populations that had different levels of phosphine resistance. Evaluation was conducted by using the Phosphine Tolerance Test (PTT), with exposure of the adult stage for 15, 30, 60, 90, 150 and 300 min at 3000 ppm. At the end of these intervals (separate bioassays for each time interval), the insects were transferred to Petri dishes, in which recovery was recorded at different time intervals (2 h, 1, 2 and 7 days). The majority of susceptible populations of all species were instantly immobilized even in the shortest exposure period (15 min), in contrast with resistant populations that were active even after 300 min. After exposure to phosphine, populations and exposure time affected mortality of susceptible populations, whereas resistant populations recovered regardless of species and exposure time. Additional bioassays at the concentrations of 500, 1000, 2000 and 3000 ppm for 1, 3, 5, 20, 30 and 40 h showed the presence of the "sweet spot", i.e., decrease of mortality with the increase of concentration. In fact, for most of the tested species, the "sweet spot" appeared in 1000 and 2000 ppm at a 5-h exposure time, regardless of the level of resistance to phosphine. This observation is particularly important both in terms of the assessment of resistance and in the context of non-linear recovery at elevated concentrations, indicating the occurrence of strong hormetic reversals in phosphine efficacy.
Topics: Animals; Food Parasitology; Fumigation; Insecticide Resistance; Insecticides; Phosphines; Toxicity Tests; Tribolium; Weevils
PubMed: 33594183
DOI: 10.1038/s41598-021-83463-y -
International Journal of Environmental... Mar 2023Aluminum phosphide is a highly effective insecticide for fumigation in granaries and is often used in rural grain storage. However, people's awareness of its toxicity is...
Aluminum phosphide is a highly effective insecticide for fumigation in granaries and is often used in rural grain storage. However, people's awareness of its toxicity is not strong. A case of acute inhalation toxicity of phosphine caused by the use of aluminum phosphide to fumigate a granary is reported here. The case presented with aspiration pneumonia and acute left heart failure. The patient was cured using comprehensive life support treatment, including respiratory support, antiarrhythmic treatment, and blood pressure maintenance with vasoactive drugs. There is no specific antidote for phosphine poisoning at present, and the comprehensive application of restricted fluid resuscitation, high-dose glucocorticoid shock, vasoactive drugs and bedside hemofiltration is significant in improving the prognosis of patients. It is also important to remind people to pay attention to their own protection in the process of using aluminum phosphide.
Topics: Humans; Phosphines; Aluminum Compounds; Insecticides
PubMed: 36981930
DOI: 10.3390/ijerph20065021 -
Inorganic Chemistry May 2021Low-toxic InP quantum dots (QDs) as an ideal candidate for Cd-based QDs have tremendous potential for next-generation commercial display and biological detection...
Low-toxic InP quantum dots (QDs) as an ideal candidate for Cd-based QDs have tremendous potential for next-generation commercial display and biological detection applications. However, the progress in biological detection is still far behind that of the Cd-based QDs. This is mainly because the InP-based QDs are of inferior stability and photoluminescence quantum yield (PL QY) in aqueous solution. Here, PL QY of 65% and excellent stability of InP/GaP/ZnS QD@SiO nanoparticles have been successfully synthesized a silica coating method. The containing thiol-capped hydrophobic InP/GaP/ZnS QDs were pre-silanized with waterless, ammonia-free hydrolysis tetraethyl orthosilicate, and subsequently, an outer silica shell was generated in the reverse microemulsion. The corresponding QD-based fluorescence-linked immunosorbent assay exhibits a high sensitivity of 0.9 ng mL for C-reactive protein and the broad detection range of 1-1000 ng mL, which was close to that of the state-of-the-art Cd-based QD@SiO nanoparticles and had the highest sensitivity of Cd-free QDs so far. This work provides a very successful silica coating method for the containing thiol-capped hydrophobic QDs and the QDs highly sensitive to water and oxygen, and the obtained InP/GaP/ZnS QD@SiO nanoparticles were considered as the robust, biocompatible, and promising Cd-free fluorescent labels for the further ultra-sensitive detection.
Topics: Biocompatible Materials; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Indium; Particle Size; Phosphines; Quantum Dots; Silicon Dioxide
PubMed: 33847486
DOI: 10.1021/acs.inorgchem.1c00304 -
Biochemistry Sep 2020Protein biochemistry protocols typically include disulfide bond reducing agents to guard against unwanted thiol oxidation and protein aggregation. Commonly used...
Protein biochemistry protocols typically include disulfide bond reducing agents to guard against unwanted thiol oxidation and protein aggregation. Commonly used disulfide bond reducing agents include dithiothreitol, β-mercaptoethanol, glutathione, and the tris(alkyl)phosphine compounds tris(2-carboxyethyl)phosphine (TCEP) and tris(3-hydroxypropyl)phosphine (THPP). While studying the catalytic activity of the NAD(P)H-dependent enzyme Δ-pyrroline-5-carboxylate reductase, we unexpectedly observed a rapid non-enzymatic chemical reaction between NAD and the reducing agents TCEP and THPP. The product of the reaction exhibits a maximum ultraviolet absorbance peak at 334 nm and forms with an apparent association rate constant of 231-491 M s. The reaction is reversible, and nuclear magnetic resonance characterization (H, C, and P) of the product revealed a covalent adduct between the phosphorus of the tris(alkyl)phosphine reducing agent and the C4 atom of the nicotinamide ring of NAD. We also report a 1.45 Å resolution crystal structure of short-chain dehydrogenase/reductase with the NADP-TCEP reaction product bound in the cofactor binding site, which shows that the adduct can potentially inhibit enzymes. These findings serve to caution researchers when using TCEP or THPP in experimental protocols with NAD(P). Because NAD(P)-dependent oxidoreductases are widespread in nature, our results may be broadly relevant.
Topics: Bacterial Proteins; Burkholderia; Disulfides; Dithiothreitol; NAD; Oxidation-Reduction; Phosphines; Protein Conformation; Protein Domains; Reducing Agents; Short Chain Dehydrogenase-Reductases
PubMed: 32841567
DOI: 10.1021/acs.biochem.0c00490