2010 AUG 13 – (VerticalNews.com) — A report, ‘New 1alpha,25-dihydroxy-19-norvitamin D3 analogs with a frozen A-ring conformation,’ is newly published data in The Journal of Steroid Biochemistry and Molecular Biology. Return to Tiffany™ Heart lock charm to recent research published in the Journal of Steroid Biochemistry and Molecular Biology, “We have recently described the synthesis of 1alpha,25-dihydroxy-19-norvitamin D3 analogs 2 and 3, possessing an additional ring connecting their 3beta-oxygen and C-2. Such structural constrains prevent the A-ring conformational flexibility and the analogs exist exclusively in the alpha-chair form with their 1alpha-hydroxy groups fixed in the axial position.”
“The analogs bind very poorly to vitamin D receptor and are devoid of transcriptional activity. Rather unexpectedly, when tested in vivo in rats, they exhibited calcemic response significantly delayed compared to 1alpha,25-dihydroxyvitamin D3 (1). Such a response might be due to the metabolic conversion (ether cleavage?) of these compounds in the living organisms. It was therefore of interest to obtain and evaluate biologically the analogous compounds having an additional ring of purely hydrocarbon nature. Such analog 4 of 1alpha,25-dihydroxy-19-norvitamin D3, Return to Tiffany™ Heart tag necklace by the presence of an equatorial 1alpha-hydroxy group (beta-chair form), has been synthesized by us and tested biologically. The geometrical isomer 5 having a fixed 3beta-hydroxy group was also obtained. These compounds were formed in the Julia coupling of the sulfone derived from the Grundmann ketone, and the A-ring fragment prepared in the multi-step synthesis from the (-)-quinic acid,” wrote A. Glebocka and colleagues, University of Wisconsin, Department of Biochemistry.
The researchers concluded: “Contrary to its counterpart 5, the analog 4 retained some affinity to vitamin D receptor.”
Glebocka and colleagues published their study in the Journal of Steroid Biochemistry and Molecular Biology (New 1alpha,25-dihydroxy-19-norvitamin D3 analogs with a frozen A-ring conformation. Journal of Steroid Biochemistry and Molecular Biology, 2010;121(1-2):46-50).
For additional information, contact A. Glebocka, University of Wisconsin-Madison, Dept. of Biochemistry, 433 Babcock Drive, Madison, WI 53706 USA.2010 AUG 13 – (VerticalNews.com) — Researchers detail in ‘Do [all]-S,S’-dioxide oligothiophenes show electronic and optical properties of oligoenes and/or of oligothiophenes,’ new data in chemical research. According to recent research published in the Journal of the American Chemical Society, “A Return to Tiffany™ Heart tag pendant photophysical and spectroscopic (electronic and Raman) study guided by density functional theory, DFT, CIS, and correlated ab initio calculations has been performed on a series of fully oxidized oligothiophenes with variable chain length, and up to four rings. A comparison with the properties of oligoenes and oligothiophenes is proposed.”
“Absorption, fluorescence, lifetimes, flash-photolysis, phosphorescence, two-photon absorption, Raman, resonance Raman, and thermospectroscopy data are collected and interpreted according to the obtained theoretical results. The interest is focused on the ground electronic state and in the low-lying excited electronic states. Full oxygenation of the sulfur atoms of oligothiophenes results in: (i) Return to Tiffany™ Oval tag pendant inter-ring isomerization such as observed from the absorption spectra; (ii) an effective quenching of fluorescence, and (iii) the appearance of dual emission. The emission features are explained by the interference of a dipole-allowed and a dipole-forbidden singlet excited states leading to simultaneous lighting from a local Frenkel and an intramolecular charge transfer photon-releasing configurations. These two excited states contribute to the broadening of the light emission spectrum,” wrote Oliva M. Moreno and colleagues, University of Malaga, Department of Physical Chemistry.
The researchers concluded: “These properties highlight the similarity of these samples to that of oligoenes with comparable number of pi-electrons.”
Moreno and colleagues published their study in the Journal of the American Chemical Society (Do [all]-S,S’-dioxide oligothiophenes show electronic and optical properties of oligoenes and/or of oligothiophenes? Journal of the American Return to Tiffany™ Round tag pendant Society, 2010;132(17):6231-42).
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