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The absolute configuration of was deduced by vibrational circular dichroism together with the evaluation of the Flack and Hooft X-ray parameters. Vibrational circular dichroism exciton coupling, using the carbonyl group signals, confirmed the absolute configuration of . In addition, sodium borohydride reduction of the 11,13-double bond of 6-epi-desacetyllaurenobiolide () yields an almost equimolecular mixture of C11 epimers, while reduction of the same double bond of 6-epi-laurenobiolide () provided almost exclusively the (11S) diastereoisomer .
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http://dx.doi.org/10.1002/chir.22420 | DOI Listing |
Int J Mol Sci
August 2025
Department of Organic Chemistry, University of Debrecen, P.O. Box 400, 4002 Debrecen, Hungary.
Inspired by naturally occurring -isochromans such as penicisteckins, we envisaged the first synthesis of biaryl-type -1-arylisochromans containing a stereogenic -trisubstituted biaryl axis. We achieved the stereoselective synthesis of 5,5'-linked heterodimeric -isochromans containing both central and axial chirality elements by performing diastereoselective Suzuki-Miyaura biaryl coupling reactions on two optically active 1-arylpropan-2-ol derivatives, followed by two oxa-Pictet-Spengler cyclizations with aryl aldehydes or methoxymethyl chloride. We studied the diastereoselectivity of the cyclization step, separated the stereoisomeric products with chiral preparative HPLC and determined the absolute configuration through a combination of vibrational circular dichroism (VCD), NMR and single-crystal X-ray diffraction analysis.
View Article and Find Full Text PDFJ Phys Chem B
August 2025
Biophysical Chemistry Laboratory, Physical Chemistry Section, Department of Chemistry, Jadavpur University, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
Higher-ordered nucleic acid structures like triplex and quadruplex forms have been the center of attention of the current research field of medicinal chemistry. The triplex is formed through the sequence-specific association of a single-stranded, triplex-forming oligonucleotide (TFO) with nucleic acid duplex structures. In our present study, we have focused on an RNA triplex (U.
View Article and Find Full Text PDFBiomimetics (Basel)
August 2025
State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation, Tianjin University, Tianjin 300354, China.
Harbor seals, equipped with their uniquely structured whiskers, demonstrate remarkable proficiency in tracking the trajectories of prey within dark and turbid marine environments. This study experimentally investigates the wake-induced vibrations of an elastically supported whisker model placed in the wakes of circular, square, and equilateral triangular cylinders of varying dimensions. Thereafter, a machine learning model is trained to identify and classify these intrinsic responses.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
August 2025
Technische Universität Dresden, Carl Gustav Carus Faculty of Medicine, Clinic of Otorhinolaryngology, Head and Neck Surgery, Ear Research Center Dresden, Fetscherstraße 74, 01307 Dresden, Germany. Electronic address:
Myringoplasty is a routine surgery to restore the hearing of patients with a subacute and chronic tympanic membrane (TM) perforation. Electrospun scaffolds as a new art of synthetic TM replacement have a great potential to overcome the drawbacks of currently used autologous tissues due to the nano- and microfibers. Most recently with the development of tissue engineering, efforts have been made to mimic the radial and circular fiber arrangement of human TM to generate comparable acoustic vibration and mechanical stability.
View Article and Find Full Text PDFMacromol Rapid Commun
August 2025
Department of Chemistry, College of Humanities & Sciences, Nihon University, Setagaya-ku, Tokyo, Japan.
Racemic octahedral metal complexes with Δ and Λ chirality and terminal C9 or C10 alkyl chains (M-Cn, n = 9 or 10, M = Ru or Ir) are reported as the first octahedral metallomesogens that exhibit a micellar cubic (Cub) liquid-crystal phase. The space group of the Cub phase in rac-M-Cn is , and each micelle comprises eight molecules in a J-type aggregate structure. In contrast, enantiopure Δ- and Λ-M-Cn exhibit a hexagonal-columnar phase with helical stacking.
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