School of Chemistry - Research Publications

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    Photophysics and spectroscopy of 1,2-Benzazulene
    Awuku, S ; Bradley, SJ ; Ghiggino, KP ; Steer, RP ; Stevens, AL ; White, JM ; Yeow, C (Elsevier, 2021-12)
    The electronic spectroscopy and photophysics of 1,2-benzazulene (BzAz) have been examined in solution and in thin solid films, with the objective of comparing its intramolecular and intermolecular excited state decay processes with those of azulene. Unlike azulene, the S2 – S0 absorption and fluorescence spectra exhibit a clear mirror image relationship dominated by a single strong Franck-Condon active progression. Picosecond transient absorption spectra and non-linear S2 fluorescence upconversion experiments reveal lifetimes that follow a well-established energy gap law correlation, indicative of a dominant S2 – S1 decay route. Mechanistic interpretations, including the possibility of S2 singlet fission in aggregates, are discussed.
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    Synthesis of acyloin natural products by Mukaiyama hydration
    Ricca, M ; Zhang, W ; Li, J ; Fellowes, T ; White, JM ; Donnelly, PS ; Rizzacasa, MA (ROYAL SOC CHEMISTRY, 2022-05-18)
    The acyloin natural products are a family of bioactive compounds isolated from fungi and myxobacteria. The total synthesis of 7 members of the acyloin family was achieved via a HWE reaction followed by Mukaiyama-Isayama hydration, using novel Co(II) and Co(III) Schiff base SALPN complexes as catalysts for the key enone hydration step. Furthermore, we have shown that a mild acyloin rearrangement is possible under Mukaiyama hydration conditions, which was crucial in the success of this approach.
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    Palladium-Mediated CO2 Extrusion Followed by Insertion of Allenes: Translating Mechanistic Studies to Develop a One-Pot Method for the Synthesis of Alkenes
    Yang, Y ; Spyrou, B ; White, JM ; Canty, AJ ; Donnelly, PS ; O'Hair, RAJ (AMER CHEMICAL SOC, 2022-07-11)
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    Identification of Anthelmintic Bishomoscalarane Sesterterpenes from the Australian Marine Sponge Phyllospongia bergquistae and Structure Revision of Phyllolactones A-D
    Hayes, S ; Taki, AC ; Lum, KY ; Byrne, JJ ; White, JM ; Ekins, MG ; Gasser, RB ; Davis, RA (AMER CHEMICAL SOC, 2022-07-22)
    High-throughput screening of the NatureBank marine extract library (7616 samples) identified an extract derived from the Australian marine sponge Phyllospongia bergquistae with activity against Hemonchus contortus (barber's pole worm), an economically important parasitic nematode. Bioassay-guided fractionation of the CH2Cl2/MeOH extract from P. bergquistae led to the purification of four known bishomoscalarane sesterterpenes, phyllolactones A-D (1-4). The absolute configurations of phyllolactones B (2) and C (3) were determined by single-crystal X-ray diffraction analysis; literature and data analyses revealed the need for these chemical structures to be revised. Compounds 2-4 induced a lethal, skinny (Ski) phenotype in larvae of H. contortus at concentrations between 5.3 and 10.1 μM. These data indicate that the bishomoscalarane sesterterpene structure class warrants further investigation for nematocidal or nematostatic activity.
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    Synthesis of the Alkylsulfonate Metabolites Cysteinolic Acid, 3-Amino-2-hydroxypropanesulfonate, and 2,3-Dihydroxypropanesulfonate
    Burchill, L ; Zudich, L ; van der Peet, PL ; White, JM ; Williams, SJ (AMER CHEMICAL SOC, 2022-03-18)
    Chiral hydroxy- and aminohydroxysulfonic acids are widespread in the marine and terrestrial environment. Here we report simple methods for the synthesis of d- and l-cysteinolic acid (from (Boc-d-Cys-OH)2 and (Boc-l-Cys-OH)2, respectively), R- and S-3-amino-2-hydroxypropanesulfonate (from S- and R-epichlorohydrin, respectively), and R- and S-2,3-dihydroxypropanesulfonate (from S- and R-epichlorohydrin, respectively). d-Cysteinolate bile salts were generated by coupling with cholic and chenodeoxycholic acids. A series of single-crystal 3D X-ray structures confirmed the absolute configurations of the aminosulfonates. By comparison of optical rotation, we assign naturally occurring 3-amino-2-hydroxypropanesulfonate from Gateloupia livida as possessing the R-configuration. This simple synthetic approach will support future studies of the occurrence, chemotaxonomic distribution, and metabolism of these alkylsulfonates.
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    Design of Calcium-Based Metal-Organic Frameworks by the Solvent Effect and Computational Investigation of Their Potential as Drug Carriers
    Alavijeh, RK ; Akhbari, K ; Bernini, MC ; Garcia Blanco, AA ; White, JM (AMER CHEMICAL SOC, 2022-05-04)
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    Some new antimicrobial/antioxidant nanostructure zinc complexes: Synthesis, crystal structure, Hirshfeld surface analyses and thermal behavior
    Akbari, Z ; Montazerozohori, M ; Naghiha, R ; Hayati, P ; Micale, N ; Cristani, M ; Bruno, G ; White, JM (Elsevier BV, 2022-01-01)
    In this study, the synthesis and characterization of a new bidentate ligand and some its zinc halide/pseudohalide complexes and nano-structures are described. The crystal structures of the ligand and its zinc nitrate complex as typical examples were determined by single crystal X-ray diffraction. Hirshfeld surface analysis of these structures provided insight into the various intra and inter-molecular interactions and therefore a description of the supramolecular structure for the ligand and its zinc nitrate complex in solid state. Furthermore, the thermal behavior of the complexes was established by TG/DTG/DTA curves analysis. Moreover an antibacterial bioassay of the zinc complexes was been performed in vitro against two gram-positive (Staphylococcus aureus and Bacillus subtilis) and two gram negative (Escherichia coli and Pseudomonas aeruginosa)] bacterial strains. The antifungal activities of the compounds against two fungal strains of Aspergilus niger and Candida albicans were also investigated. The antioxidant capabilities of the Schiff base ligand and its zinc complexes were determined by the in vitro methods of ABTS and DPPH as compared with the standard Trolox. Finally, ZnO nanoparticles were synthesized by direct calcination of the zinc iodide complex at 550 °C under air atmosphere confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX).
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    Sonochemical synthesis and crystal structure of copper(II)-based biodegradable antibacterial scaffold
    Salimi, S ; Akhbari, K ; Farnia, SMF ; White, JM (ELSEVIER, 2022-11-05)
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    Synthesis and fluorine-18 radiolabeling of a phospholipid as a PET imaging agent for prostate cancer
    Kwan, KH ; Burvenich, IJG ; Centenera, MM ; Goh, YW ; Rigopoulos, A ; Dehairs, J ; Swinnen, JV ; Raj, GV ; Hoy, AJ ; Butler, LM ; Scott, AM ; White, JM ; Ackermann, U (Elsevier, 2021)
    INTRODUCTION: Altered lipid metabolism and subsequent changes in cellular lipid composition have been observed in prostate cancer cells, are associated with poor clinical outcome, and are promising targets for metabolic therapies. This study reports for the first time on the synthesis of a phospholipid radiotracer based on the phospholipid 1,2-didocosahexaenoyl-sn-glycero-3-phosphocholine (PC44:12) to allow tracking of polyunsaturated lipid tumor uptake via PET imaging. This tracer may aid in the development of strategies to modulate response to therapies targeting lipid metabolism in prostate cancer. METHODS: Lipidomics analysis of prostate tumor explants and LNCaP tumor cells were used to identify PC44:12 as a potential phospholipid candidate for radiotracer development. Synthesis of phosphocholine precursor and non-radioactive standard were optimised using click chemistry. The biodistribution of a fluorine-18 labeled analogue, N-{[4-(2-[18F]fluoroethyl)-2,3,4-triazol-1-yl]methyl}-1,2-didocosahexaenoyl-sn-glycero-3-phosphocholine ([18F]2) was determined in LNCaP prostate tumor-bearing NOD SCID gamma mice by ex vivo biodistribution and PET imaging studies and compared to biodistribution of [18F]fluoromethylcholine. RESULTS: [18F]2 was produced with a decay-corrected yield of 17.8 ± 3.7% and an average radiochemical purity of 97.00 ± 0.89% (n = 6). Molar activity was 85.1 ± 3.45 GBq/μmol (2300 ± 93 mCi/μmol) and the total synthesis time was 2 h. Ex vivo biodistribution data demonstrated high liver uptake (41.1 ± 9.2%ID/g) and high splenic uptake (10.9 ± 9.1%ID/g) 50 min post-injection. Ex vivo biodistribution showed low absolute tumor uptake of [18F]2 (0.8 ± 0.3%ID/g). However, dynamic PET imaging demonstrated an increase over time of the relative tumor-to-muscle ratio with a peak of 2.8 ± 0.5 reached 1 h post-injection. In contrast, dynamic PET of [18F]fluoromethylcholine demonstrated no increase in tumor-to-muscle ratios due to an increase in both tumor and muscle over time. Absolute uptake of [18F]fluoromethylcholine was higher and peaked at 60 min post injection (2.25 ± 0.29%ID/g) compared to [18F]2 (1.44 ± 0.06%ID/g) during the 1 h dynamic scan period. CONCLUSIONS AND ADVANCES IN KNOWLEDGE: This study demonstrates the ability to radiolabel phospholipids and indicates the potential to monitor the in vivo distribution of phospholipids using fluorine-18 based PET.