Cultured rat astrocytes and C6 rat glioma were used as a differential screen for a variety of 1,2,3,4-tetrahydroisoquinoline (THI) derivatives. Compound 1 [1-(biphenyl-4-ylmethyl)-1,2,3,4-tetrahydroisoquinoline-6,7-diol hydrochloride] selectively blocked the growth of C6 glioma leaving normal astrocytes relatively unaffected. The potential for clinical utility of 1 was further substantiated in human gliomas and other tumor cell lines. Preliminary SAR of this activity was characterized by synthesis and testing of several THI and conformationally flexible variants.
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http://dx.doi.org/10.1021/jm060020x | DOI Listing |
J Org Chem
December 2024
Chemistry and Materials Program, College of Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Kohto-ku, Tokyo 135-8548, Japan.
Both enantiomers of 2-ethylquinazolin-4-ones bearing -CHO/CDO and CHO/CHO phenyl groups at the N3 position were prepared. These are isotopic atropisomeric compounds based on a remote and conformationally flexible H/D and C/C discrimination, and it was found that a CHCl solution of -CHO/CDO derivative shows a slight specific optical rotation. Furthermore, diastereomeric quinazolinone derivatives bearing a chiral carbon were prepared, and their stereochemical purities and rotational stability as well as the isotopic atropisomerism were verified by H NMR and chiral high-performance liquid chromatography (HPLC) analyses.
View Article and Find Full Text PDFInorg Chem
December 2024
Department of Chemistry, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States.
Both cyclic "crown" and acyclic "tiara" polyethers have been recognized as useful for the binding of metal cations and enabling the assembly of multimetallic complexes. However, the properties of heterobimetallic complexes built upon acyclic polyethers have received less attention than they deserve. Here, the synthesis and characterization of a family of eight redox-active heterobimetallic complexes that pair a nickel center with secondary redox-inactive cations (K, Na, Li, Sr, Ca, Zn, La, and Lu) bound in acyclic polyether "tiara" moieties are reported.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Nanostructured Molecular Systems and Materials group, Organic Chemistry Department, Universidad Autónoma de Madrid, Madrid 28049, Spain.
If we aim to develop efficient synthetic models of protein receptors and enzymes, we must understand the relationships of intra- and intermolecular interactions between hosts and guests and how they mutually influence their conformational energy landscape so as to adapt to each other to maximize binding energies and enhance substrate selectivities. Here, we introduce a novel design of cofacial (Zn)bisporphyrin cages based on dynamic imine bonding, which is synthetically simple, but at the same time highly robust and versatile, affording receptors composed of only -hybridized C and N atoms. The high structural rigidity of these cages renders them ideal hosts for ditopic molecules that can fit into the cavity and bind to both metal centers, leading to association constants as high as 10 M in chloroform.
View Article and Find Full Text PDFNature
December 2024
Protein-Nucleic Acid Interaction Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA.
Much of the human genome is transcribed into RNAs, many of which contain structural elements that are important for their function. Such RNA molecules-including those that are structured and well-folded-are conformationally heterogeneous and flexible, which is a prerequisite for function, but this limits the applicability of methods such as NMR, crystallography and cryo-electron microscopy for structure elucidation. Moreover, owing to the lack of a large RNA structure database, and no clear correlation between sequence and structure, approaches such as AlphaFold for protein structure prediction do not apply to RNA.
View Article and Find Full Text PDFNature
December 2024
Protein-Nucleic Acid Interaction Section, Center for Structural Biology, National Cancer Institute, Frederick, MD, USA.
RNA conformational diversity has fundamental biological roles, but direct visualization of its full conformational space in solution has not been possible using traditional biophysical techniques. Using solution atomic force microscopy, a deep neural network and statistical analyses, we show that the ribonuclease P (RNase P) RNA adopts heterogeneous conformations consisting of a conformationally invariant core and highly flexible peripheral structural elements that sample a broad conformational space, with amplitudes as large as 20-60 Å in a multitude of directions, with very low net energy cost. Increasing Mg drives compaction and enhances enzymatic activity, probably by narrowing the conformational space.
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