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RSC Advances May 2024Cyclic -sulfonyl aldimines are well-known aza-[2]-synthons for various [2 + ] annulation reactions. Herein we describe a novel base mediated [2 + 1] annulation and a...
Base mediated aza-[2 + 1] annulation and regioselective aziridine ring-opening cascade: mild synthesis of functionalized -amino ketones from cyclic -sulfonyl aldimines and -carbonyl sulfonium salts.
Cyclic -sulfonyl aldimines are well-known aza-[2]-synthons for various [2 + ] annulation reactions. Herein we describe a novel base mediated [2 + 1] annulation and a regioselective aziridine ring-opening reaction cascade, which provides an efficient and distinct synthetic strategy from readily available cyclic -sulfonyl aldimines and -carbonyl sulfonium salts leading to -amino ketone derivatives through the corresponding fused tri-substituted aziridines. This one-pot, two-step process involves formation of C-C and C-N bonds and subsequent cleavage of a C-N bond. The features of the developed reaction include the use of mild reaction conditions, broad substrate scope, and excellent yields. The synthetic utility of this approach was demonstrated by gram-scale operation and further product derivatizations.
PubMed: 38808243
DOI: 10.1039/d4ra02817a -
Frontiers in Chemistry 2023Aziridine had different regioselective ring openings depending on the functional group of its alkyl substituent. In the case of the alkyl group bearing γ-ketone at the...
Aziridine had different regioselective ring openings depending on the functional group of its alkyl substituent. In the case of the alkyl group bearing γ-ketone at the C2 substituent of aziridine, the ring opening by the hydroxy nucleophile from HO occurred by attacking the aziridine carbon at the C2 position. This reaction proceeded efficiently in the presence of CFCOH. Interestingly, the same starting aziridine ring bearing the alkyl substituent at the C2 position with the γ-silylated hydroxy group instead of γ-ketone led to the ring-opening reaction by the same oxygen nucleophile at the unsubstituted C3 position, with the breakage of the bond between aziridine N1 nitrogen and carbon at C3. These reaction products were cyclized to afford substituted pyrrolidine and piperidine rings with representative examples of congeners of pseudoconhydrine and monomorine.
PubMed: 37927563
DOI: 10.3389/fchem.2023.1280633 -
Bone Marrow Transplantation Feb 2024Conditioning protocols for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) are being developed continuously to improve their anti-leukemic...
Comparison of fludarabine/melphalan (FluMel) with fludarabine/melphalan/BCNU or thiotepa (FBM/FTM) in patients with AML in first complete remission undergoing allogeneic hematopoietic stem cell transplantation - a registry study on behalf of the EBMT Acute Leukemia Working Party.
Conditioning protocols for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) are being developed continuously to improve their anti-leukemic efficacy and reduce their toxicity. In this study, we compared the conditioning protocol of fludarabine with melphalan 140 mg/m (FluMel) with conditioning protocols based on this same backbone but with an additional alkylating agent i.e., either fludarabine/BCNU (also known as carmustine)/melphalan (FBM), or fludarabine/thiotepa/melphalan (FTM) 110 mg/m. We included 1272 adult patients (FluMel, n = 1002; FBM/FTM, n = 270) with acute myeloid leukemia (AML) with intermediate/poor cytogenetic risk in first complete remission (CR) from the registry of the EBMT Acute Leukemia Working Party. Despite patients in the FBM/FTM group were older (64.1 years vs. 59.8 years, p < 0.001) and had a worse Karnofsky performance score (KPS < 90, 33% vs. 24%, p = 0.003), they showed a better overall survival (OS) (2 y OS: 68.3% vs. 58.1%, p = 0.02) and less non-relapse mortality (NRM) (2 y NRM: 15.8% vs. 22.2%, p = 0.009) compared to patients treated with FluMel. No significant differences were observed in relapse incidence (RI) (2 y RI: 24.9% vs. 23.7%, p = 0.62). In conclusion, the addition of a second alkylating agent (BCNU/carmustine or thiotepa) to FluMel as FBM/FTM conditioning, improves OS in AML patients in first CR with intermediate/poor risk cytogenetics after allo-HCT.
Topics: Humans; Adult; Melphalan; Carmustine; Thiotepa; Busulfan; Antineoplastic Combined Chemotherapy Protocols; Transplantation Conditioning; Transplantation, Homologous; Leukemia, Myeloid, Acute; Recurrence; Pathologic Complete Response; Hematopoietic Stem Cell Transplantation; Graft vs Host Disease; Alkylating Agents; Retrospective Studies; Vidarabine
PubMed: 38040842
DOI: 10.1038/s41409-023-02150-w -
Molecules (Basel, Switzerland) Oct 2023Success of gene therapy relies on the durable expression and activity of transgene in target tissues. In vivo molecular imaging approaches using positron emission...
Success of gene therapy relies on the durable expression and activity of transgene in target tissues. In vivo molecular imaging approaches using positron emission tomography (PET) can non-invasively measure magnitude, location, and durability of transgene expression via direct transgene or indirect reporter gene imaging in target tissues, providing the most proximal PK/PD biomarker for gene therapy trials. Herein, we report the radiosynthesis of a novel PET tracer [F]AGAL, targeting alpha galactosidase A (α-GAL), a lysosomal enzyme deficient in Fabry disease, and evaluation of its selectivity, specificity, and pharmacokinetic properties in vitro. [F]AGAL was synthesized via a Cu-catalyzed click reaction between fluorinated pentyne and an aziridine-based galactopyranose precursor with a high yield of 110 mCi, high radiochemical purity of >97% and molar activity of 6 Ci/µmol. The fluorinated AGAL probe showed high α-GAL affinity with of 30 nM, high pharmacological selectivity (≥50% inhibition on >160 proteins), and suitable pharmacokinetic properties (moderate to low clearance and stability in plasma across species). In vivo [F]AGAL PET imaging in mice showed high uptake in peripheral organs with rapid renal clearance. These promising results encourage further development of this PET tracer for in vivo imaging of α-GAL expression in target tissues affected by Fabry disease.
Topics: Mice; Animals; alpha-Galactosidase; Fabry Disease; Positron-Emission Tomography; Radiopharmaceuticals; Hydrolases; Fluorine Radioisotopes
PubMed: 37894622
DOI: 10.3390/molecules28207144 -
Cells Jul 2023Tumor therapy escape due to undesired side effects induced by treatment, such as prosurvival autophagy or cellular senescence, is one of the key mechanisms of resistance...
Tumor therapy escape due to undesired side effects induced by treatment, such as prosurvival autophagy or cellular senescence, is one of the key mechanisms of resistance that eventually leads to tumor dormancy and recurrence. Glioblastoma is the most frequent and practically incurable neoplasm of the central nervous system; thus, new treatment modalities have been investigated to find a solution more effective than the currently applied standards based on temozolomide. The present study examined the newly synthesized compounds of aziridine-hydrazide hydrazone derivatives to determine their antineoplastic potential against glioblastoma cells in vitro. Although the output of our investigation clearly demonstrates their proapoptotic activity, the cytotoxic effect appeared to be blocked by treatment-induced autophagy, the phenomenon also detected in the case of temozolomide action. The addition of an autophagy inhibitor, chloroquine, resulted in a significant increase in apoptosis triggered by the tested compounds, as well as temozolomide. The new aziridine-hydrazide hydrazone derivatives, which present cytotoxic potential against glioblastoma cells comparable to or even higher than that of temozolomide, show promising results and, thus, should be further investigated as antineoplastic agents. Moreover, our findings suggest that the combination of an apoptosis inducer with an autophagy inhibitor could optimize chemotherapeutic efficiency, and the addition of an autophagy inhibitor should be considered as an optional adjunctive therapy minimizing the risk of tumor escape from treatment.
Topics: Humans; Glioblastoma; Temozolomide; Chloroquine; Hydrazones; Hydrazines; Antineoplastic Agents; Autophagy; Aziridines
PubMed: 37508570
DOI: 10.3390/cells12141906 -
Lipid Isobaric Mass Tagging for Enhanced Relative Quantification of Unsaturated -Positional Isomers.ACS Measurement Science Au Apr 2024Changes in the levels of lipid -positional isomers are associated with perturbation of the physiological environment within the biological system. Consequently, knowing...
Changes in the levels of lipid -positional isomers are associated with perturbation of the physiological environment within the biological system. Consequently, knowing the concentrations of these lipids holds significant importance for unraveling their involvement in disease diagnosis and pathological mechanisms. However, existing methods for lipid quantification often fall short in accuracy due to the structural diversity and isomeric forms of lipids. To address this challenge, we have developed an aziridine-based isobaric tag labeling strategy that allows (i) differentiation and (ii) enhanced relative quantification of lipid -positional isomers from distinct samples in a single run. The methodology enabled by aziridination, isobaric tag labeling, and lithiation has been applied to various phospholipids, enabling the determination of the -positions of fatty acyl chains and enhanced relative quantification. The analysis of lipid extracts demonstrated the enhanced determination of the concentration ratios of lipid isomers by measuring the intensity ratios of mass reporters released from -positional diagnostic ions. Moreover, we applied the method to the analysis of human colon cancer plasma. Intriguingly, 17 PC lipid -positional isomers were identified and quantified simultaneously, and among them, 7 showed significant abundance changes in the colon cancer plasma, which can be used as potential plasma markers for diagnosis of human colon cancer.
PubMed: 38645577
DOI: 10.1021/acsmeasuresciau.3c00062 -
Redox Biology Jun 2024Protein disulfide isomerases (PDIs) are involved in many intracellular and extracellular processes, including cell adhesion and cytoskeletal reorganisation, but their...
Protein disulfide isomerases (PDIs) are involved in many intracellular and extracellular processes, including cell adhesion and cytoskeletal reorganisation, but their contribution to the regulation of fenestrations in liver sinusoidal endothelial cells (LSECs) remains unknown. Given that fenestrations are supported on a cytoskeleton scaffold, this study aimed to investigate whether endothelial PDIs regulate fenestration dynamics in primary mouse LSECs. PDIA3 and PDIA1 were found to be the most abundant among PDI isoforms in LSECs. Taking advantage of atomic force microscopy, the effects of PDIA1 or PDIA3 inhibition on the fenestrations in LSECs were investigated using a classic PDIA1 inhibitor (bepristat) and novel aromatic N-sulfonamides of aziridine-2-carboxylic acid derivatives as PDIA1 (C-3389) or PDIA3 (C-3399) inhibitors. The effect of PDIA1 inhibition on liver perfusion was studied in vivo using dynamic contrast-enhanced magnetic resonance imaging. Additionally, PDIA1 inhibitors were examined in vitro in LSECs for effects on adhesion, cytoskeleton organisation, bioenergetics, and viability. Inhibition of PDIA1 with bepristat or C-3389 significantly reduced the number of fenestrations in LSECs, while inhibition of PDIA3 with C-3399 had no effect. Moreover, the blocking of free thiols by the cell-penetrating N-ethylmaleimide, but not by the non-cell-penetrating 4-chloromercuribenzenesulfonate, resulted in LSEC defenestration. Inhibition of PDIA1 did not affect LSEC adhesion, viability, and bioenergetics, nor did it induce a clear-cut rearrangement of the cytoskeleton. However, PDIA1-dependent defenestration was reversed by cytochalasin B, a known fenestration stimulator, pointing to the preserved ability of LSECs to form new pores. Importantly, systemic inhibition of PDIA1 in vivo affected intra-parenchymal uptake of contrast agent in mice consistent with LSEC defenestration. These results revealed the role of intracellular PDIA1 in the regulation of fenestration dynamics in LSECs, and in maintaining hepatic sinusoid homeostasis.
Topics: Animals; Male; Mice; Cell Adhesion; Cells, Cultured; Cytoskeleton; Endothelial Cells; Enzyme Inhibitors; Liver; Protein Disulfide-Isomerases
PubMed: 38669864
DOI: 10.1016/j.redox.2024.103162 -
Materials (Basel, Switzerland) Jun 2024To use polylactic acid in demanding technical applications, sufficient long-term thermal stability is required. In this work, the thermal aging of polylactic acid (PLA)...
To use polylactic acid in demanding technical applications, sufficient long-term thermal stability is required. In this work, the thermal aging of polylactic acid (PLA) in the solid phase at 100 °C and 150 °C is investigated. PLA has only limited aging stability without the addition of stabilizers. Therefore, the degradation mechanism in thermal aging was subsequently investigated in more detail to identify a suitable stabilization strategy. Investigations using nuclear magnetic resonance spectroscopy showed that, contrary to expectations, even under thermal aging conditions, hydrolytic degradation rather than oxidative degradation is the primary degradation mechanism. This was further confirmed by the investigation of suitable stabilizers. While the addition of phenols, phosphites and thioethers as antioxidants leads only to a limited improvement in aging stability, the addition of an additive composition to provide hydrolytic stabilization results in extended durability. Efficient compositions consist of an aziridine-based hydrolysis inhibitor and a hydrotalcite co-stabilizer. At an aging temperature of 100 °C, the time until significant polymer chain degradation occurs is extended from approx. 500 h for unstabilized polylactic acid to over 2000 h for stabilized polylactic acid.
PubMed: 38894026
DOI: 10.3390/ma17112761 -
Frontiers in Chemistry 2024
PubMed: 38800579
DOI: 10.3389/fchem.2024.1421449 -
The Journal of Organic Chemistry Mar 2024Sp-enriched small molecules play a critical role in developing drug candidates. While designing analogues with greater sp character, a methodology utilizing a less...
Sp-enriched small molecules play a critical role in developing drug candidates. While designing analogues with greater sp character, a methodology utilizing a less explored cyclic-aziridine amide ring-opening reaction to generate sp-enriched scaffolds has been developed and reported. This methodology enables rapid access to substructures with higher fsp values, attracting greater attention within the past few decades. The reaction exhibits a wide reaction scope, featuring a highly sterically hindered phenolic ether, thiophenolic ethers, protected aniline formations, and aliphatic/heteroaromatic ring-containing aziridine amides as substrates. Additionally, this reaction provides access to congested tertiary ether formations through regioselective transformation, applicable to an extensive range of drug discovery targets, construction of complex small molecules, and natural product syntheses. The scaffolds developed show improved physicochemical properties.
PubMed: 38340064
DOI: 10.1021/acs.joc.3c02952