The observation that 17-cyclopropylmethylmorphinan derivatives without the 4,5-epoxy ring showed more κ selectivity than those with a 4,5-epoxy ring led us to develop a working hypothesis: the position of the plane composed of the A and B rings would influence the opioid receptor type selectivity and that the decrease in the torsion angle C11-C12-C13-C14 could improve the κ selectivity. Consistent with our hypothesis, KNT-42 with an N-cyclopropylmethyl propellane structure, whose A and B rings were fixed in a torsion angle of approximately 0°, showed κ selective agonist activity.
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http://dx.doi.org/10.1016/j.bmcl.2011.04.147 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Graft-through ring-opening metathesis polymerization (ROMP) of norbornene-terminated macromonomers (MMs) prepared using various polymerization methods has been extensively used for the synthesis of bottlebrush (co)polymers, yet the potential of ROMP for the synthesis of MMs that can subsequently be polymerized by graft-through ROMP to produce new bottlebrush compositions remains untapped. Here, we report an efficient "ROMP-of-ROMP" method that involves the synthesis of norbornene-terminated poly(norbornene imide) (PNI)-based MMs that, following ROMP, provide new families of bottlebrush (co)polymers and "brush-on-brush" hierarchical architectures. In the bulk state, the organization of the PNI pendants drives bottlebrush backbone extension to enable rapid assembly of asymmetric lamellar morphologies with large asymmetry factors.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
End-user feedback early in product development is important for optimizing multipurpose prevention technologies for HIV and pregnancy prevention. We evaluated the acceptability of the 90-day dapivirine levonorgestrel ring (DPV-LNG ring) used for 14 days compared to a dapivirine-only ring (DVR-200mg) in MTN-030/IPM 041 (n = 23), and when used for 90 days cyclically or continuously in MTN-044/IPM 053/CCN019 (n = 25). We enrolled healthy, non-pregnant, HIV-negative women aged 18-45 in Pittsburgh, PA and Birmingham, AL (MTN-030 only).
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Institute of Inorganic Chemistry, Czech Academy of Sciences, 250 68 Husinec-Řež, Czech Republic.
Co-pyrolysis reactions of BBr with SBr at 350 °C yielded the brominated thiaboranes -SBBr (1), -1-SBBr (2) and -SBBr (3), confirmed by high-resolution mass spectrometry, experimental and computational B NMR spectroscopy. The strong Br(σ-hole)⋯Br(ring) attraction has been the decisive energy contribution in the crystal of 1.
View Article and Find Full Text PDFChemistry
January 2025
The University of Manchester, Manchester Institute of Biotechnology, 131 Princess Street, M1 7DN, Manchester, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
The natural product synthesis of brevione J undergoes a cascade of reactions including an oxidative desaturation and a ring-expansion. The C1-C2 desaturation of brevione B is catalyzed by the nonheme iron dioxygenase BrvJ using one molecule of O2 and a-ketoglutarate (aKG). However, whether the subsequent oxidative ring expansion reaction is also catalyzed by the same enzyme is unknown and remains controversial.
View Article and Find Full Text PDFChembiochem
January 2025
Renmin University of China, Chemistry, No.59 Zhongguangcun Street, Haidian District, 100872, Beijing, CHINA.
BTG13, a non-heme iron-dependent enzyme with a distinctive coordination environment of four histidines and a carboxylated lysine, has been found to catalyze the cleavage of the C4a-C10 bond in anthraquinone. Contrary to typical dioxygenase mechanisms, our quantum mechanical/molecular mechanical (QM/MM) calculations reveal that BTG13 functions more like a monooxygenase. It selectively inserts an oxygen atom into the C10-C4a bond, creating a lactone species that subsequently hydrolyzes, leading to the formation of a ring-opened product.
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