Correction to "Synthetic, Functional Thymidine-Derived Polydeoxyribonucleotide Analogues from a Six-Membered Cyclic Phosphoester".
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ABSTRACT:
SUBMITTER: Tsao YT
PROVIDER: S-EPMC8154422 | biostudies-literature | 2018 Mar
REPOSITORIES: biostudies-literature
Publications
Correction to "Synthetic, Functional Thymidine-Derived Polydeoxyribonucleotide Analogues from a Six-Membered Cyclic Phosphoester".
Tsao Yi-Yun Timothy YT Wooley Karen L KL
Journal of the American Chemical Society 20180306 11
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Project description:A grand challenge that crosses synthetic chemistry and biology is the scalable production of functional analogues of biomacromolecules. We have focused our attention on the use of deoxynucleoside building blocks bearing non-natural bases to develop a synthetic methodology that allows for the construction of high molecular weight deoxynucleotide polymers. Our six-membered cyclic phosphoester ring-opening polymerization strategy is demonstrated, herein, by an initial preparation of novel polyphosphoesters, comprised of butenyl-functionalized deoxyribonucleoside repeat units, connected via 3',5'-backbone linkages. A thymidine-derived bicyclic monomer, 3',5'-cyclic 3-(3-butenyl) thymidine ethylphosphate, was synthesized in two steps directly from thymidine, via butenylation and diastereoselective cyclization promoted by N,N-dimethyl-4-aminopyridine. Computational modeling of the six-membered 3',5'-cyclic phosphoester ring derived from deoxyribose indicated strain energies at least 5.4 kcal/mol higher than those of the six-membered monocyclic phosphoester, 2-ethoxy-1,3,2-dioxaphosphinane 2-oxide. These calculations supported the hypothesis that the strained 3',5'-cyclic monomer can promote ring-opening polymerization to afford the resulting poly(3',5'-cyclic 3-(3-butenyl) thymidine ethylphosphate)s with low dispersities (Đ < 1.10). This advanced design combines the merits of natural product-derived materials and functional, degradable polymers to provide a new platform for functional, synthetically derived polydeoxyribonucleotide-analogue materials.
| S-EPMC5451148 | biostudies-literature
Project description:The enantioselective copper-catalyzed oxidative coupling of alkenols with styrenes for the construction of dihydropyrans, isochromans, pyrans and morpholines is reported. A concise formal synthesis of a σ1 receptor ligand using this alkene carboetherification methodology was demonstrated. Ligand, solvent and base all impact reaction efficiency. DFT transition state calculations are presented.
| S-EPMC8590114 | biostudies-literature
Project description:Eight-membered nitrogen-containing heterocycles were straightforwardly produced by a nickel-catalyzed cycloetherification and subsequent Claisen rearrangement of secondary and tertiary alcohols. In particular, a one-pot transformation was achieved with tertiary alcohols in moderate to good yields. This operationally simple reaction is tolerant of many functional groups and applicable to the synthesis of various medium-sized ring nitrogen-containing heterocycles.
| S-EPMC8846577 | biostudies-literature
Project description:The seven-membered cyclic potassium alumanyl species, [{SiNMes }AlK]2 [{SiNMes }={CH2 SiMe2 N(Mes)}2 ; Mes=2,4,6-Me3 C6 H2 ], which adopts a dimeric structure supported by flanking K-aryl interactions, has been isolated either by direct reduction of the iodide precursor, [{SiNMes }AlI], or in a stepwise manner via the intermediate dialumane, [{SiNMes }Al]2 . Although the intermediate dialumane has not been observed by reduction of a Dipp-substituted analogue (Dipp=2,6-i-Pr2 C6 H3 ), partial oxidation of the potassium alumanyl species, [{SiNDipp }AlK]2 , where {SiNDipp }={CH2 SiMe2 N(Dipp)}2 , provided the extremely encumbered dialumane [{SiNDipp }Al]2 . [{SiNDipp }AlK]2 reacts with toluene by reductive activation of a methyl C(sp3 )-H bond to provide the benzyl hydridoaluminate, [{SiNDipp }AlH(CH2 Ph)]K, and as a nucleophile with BPh3 and RN=C=NR (R=i-Pr, Cy) to yield the respective Al-B- and Al-C-bonded potassium aluminaborate and alumina-amidinate products. The dimeric structure of [{SiNDipp }AlK]2 can be disrupted by partial or complete sequestration of potassium. Equimolar reactions with 18-crown-6 result in the corresponding monomeric potassium alumanyl, [{SiNDipp }Al-K(18-cr-6)], which provides a rare example of a direct Al-K contact. In contrast, complete encapsulation of the potassium cation of [{SiNDipp }AlK]2 , either by an excess of 18-cr-6 or 2,2,2-cryptand, allows the respective isolation of bright orange charge-separated species comprising the 'free' [{SiNDipp }Al]- alumanyl anion. Density functional theory (DFT) calculations performed on this moiety indicate HOMO-LUMO energy gaps in the of order 200-250 kJ mol-1 .
| S-EPMC8596455 | biostudies-literature
Project description:Our newly developed AshPhos ligand represents a significant advancement in Buchwald-Hartwig aminations, overcoming many limitations of existing ligands. Created from affordable and accessible materials, AshPhos enhances catalytic performance, especially for extremely difficult substrates, by emphasizing the principles of ligand chelation and cooperativity. Its successful synthesis and application in catalytic aminations underscore its potential for use in the sustainable synthesis of compounds important to medicinal chemistry, materials, and energy. Further studies validated AshPhos's effectiveness in coupling challenging heteroaryl bromides and chlorides with various amines, including hindered amines and those with multiple heteroatoms. Slightly elevated temperatures were essential to avoid forming inactive species, ensuring consistent catalytic turnover. A control nuclear magnetic resonance spectroscopy study suggests the formation of catalytically dormant species or deligation of AshPhos from palladium at room temperature due to the coordination of multiple substrate molecules with the palladium species. Analyses showed cost-effectiveness of AshPhos, making it a significant advancement in catalytic amination for more efficient and sustainable chemical processes. The diverse substrate scope, covering challenging coupling partners and forming over 55 substrates in good-to-excellent yields, further demonstrated the efficiency of AshPhos.
| S-EPMC11775683 | biostudies-literature
Project description:Cidofovir (HPMPC, 1), a broad-spectrum antiviral agent, is currently used to treat AIDS-related human cytomegalovirus (HCMV) retinitis and has recognized therapeutic potential for orthopox virus infections, but is limited by its low oral bioavailability. Cyclic cidofovir (2) displays decreased nephrotoxicity compared to 1, while also exhibiting potent antiviral activity. Here we describe in detail the synthesis and evaluation as prodrugs of four cHPMPC dipeptide conjugates in which the free POH of 2 is esterified by the Ser side chain alcohol group of an X-L-Ser(OMe) dipeptide: 3 (X=L-Ala), 4 (X=L-Val), 5 (X=L-Leu), and 6 (X=L-Phe). Perfusion studies in the rat establish that the mesenteric permeability to 4 is more than 20-fold greater than to 1, and the bioavailability of 4 is increased 6-fold relative to 1 in an in vivo murine model. In gastrointestinal and liver homogenates, the cHPMPC prodrugs are rapidly hydrolyzed to 2. Prodrugs 3, 4, and 5 are nontoxic at 100 microM in HFF and KB cells and in cell-based plaque reduction assays had IC 50 values of 0.1-0.5 microM for HCMV and 10 microM for two orthopox viruses (vaccinia and cowpox). The enhanced transport properties of 3-6, conferred by incorporation of a biologically benign dipeptide moiety, and the facile cleavage of the Ser-O-P linkage suggest that these prodrugs represent a promising new approach to enhancing the bioavailability of 2.
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Project description:Two new crystal structures of eight- and ten-membered cyclic bis-anisyl-phosphono-thioyl disulfanes, namely 2,5-bis-(4-meth-oxy-phen-yl)-1,6,3,4,2λ5,5λ5-dioxadi-thiadi-phospho-cane-2,5-di-thione, C16H18O4P2S4, and 2,5-bis-(4-meth-oxy-phen-yl)-1,6,3,4,2λ5,5λ5-dioxadi-thia-diphosphecane-2,5-di-thione, C18H22O4P2S4, have been determined and compared to structures of the ferrocenyl analogues. The eight-membered rings have similar conformations (TBC) but the ten-membered macrocycles are differently puckered. Structural parameters of the relevant SPSSPS motif have been analysed and are discussed in detail. Compound 1 was refined as an inversion twin and 2 was refined as a two-component rotational twin.
| S-EPMC5956339 | biostudies-literature
Project description:The first synthesis, isolation, and characterization of permidin-2-ylidene complexes of Pd(II) is reported with entry resulting from either a direct reaction with isolable six-membered N-heterocyclic carbene or from the enetetramine, arising from dimerization of the carbene. Furthermore, a simplified method to prepare N,N'-disubstituted perimidinium bromide salts, precursors to 1,3-disubstituted perimidin-2-ylidene, was achieved using ammonium bromide as a source of weak acid. Through synthesis and nuclear magnetic resonance spectroscopic analysis of a carbene-phosphinidine adduct, an interrogation of the fundamental π-bonding ability of 1,3-diisopropylperimidin-2-ylidene revealed this interaction to be weak and of a similar order to unsaturated imidazol-2-ylidenes.
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Project description:Tagging proliferating cells with thymidine analogs is an indispensable research tool; however, the issue of the potential in vivo cytotoxicity of these compounds remains unresolved. Here, we address these concerns by examining the effects of BrdU and EdU on adult hippocampal neurogenesis and EdU on the perinatal somatic development of mice. We show that, in a wide range of doses, EdU and BrdU label similar numbers of cells in the dentate gyrus shortly after administration. Furthermore, whereas the administration of EdU does not affect the division and survival of neural progenitor within 48 h after injection, it does affect cell survival, as evaluated 6 weeks later. We also show that a single injection of various doses of EdU on the first postnatal day does not lead to noticeable changes in a panel of morphometric criteria within the first week; however, higher doses of EdU adversely affect the subsequent somatic maturation and brain growth of the mouse pups. Our results indicate the potential caveats in labeling the replicating DNA using thymidine analogs and suggest guidelines for applying this approach.
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Project description:The six-membered ring (SMR) is a common structure unit for numerous material systems. These materials include, but are not limited to, the typical two-dimensional materials such as graphene, h-BN, and transition metal dichalcogenides, as well as three-dimensional materials such as beryllium, magnesium, MgB2 and Bi2Se3. Although many of these materials have already become 'stars' in materials science and condensed-matter physics, little attention has been paid to the roles of the SMR unit across a wide range of compositions and structures. In this article, we systematically analyze these materials with respect to their very basic SMR structural unit, which has been found to play a deterministic role in the occurrence of many intriguing properties and phenomena, such as Dirac electronic and phononic spectra, superconductivity and topology. As a result, we have defined this group of materials as SMR inorganic materials, opening up a new perspective on materials research and development. With their unique properties, SMR materials deserve wide attention and in-depth investigation from materials design, new physical discoveries to target-wizard applications. It is expected that SMR materials will find niche applications in next-generation information technology, renewable energy, space, etc.
| S-EPMC8294346 | biostudies-literature