539-87-7Relevant articles and documents
Conformations of Oxocane
Meyer, Walter L.,Taylor, Patterson W.,Reed, Scott A.,Leister, Marvin C.,Schneider, Hans-Joerg,et al.
, p. 291 - 298 (1992)
Conformational analysis of oxocane (oxacyclooctane) has been examined by molecular mechanics (MM2), variable-temperature 13C NMR, and lanthanide-induced shift (LIS) 1H and 13C NMR.MM2 calculations find the BC-3 conformer and its enantiomer BC-7 to be favored, with the four next best forms and their energies relative to BC-3-being BC-1 (1.1 kcal/mol), TBC-1(1.1), BC-4(1.5), and TCC-1(1.6).Barriers to pseudorotational interconversion of BC-3 and BC-7 are calculated to be 5.0 kcal/mol through BC-5 and 6.7 kcal/mol through BC-1.The former would allow fast BC-3/BC-7 equilibration even at -170 deg C, which would leave reported low-temperature 1H NMR spectra compatible with a BC-3 structure as well as BC-1.Calculated barriers for BC ring inversion and interconversion of the BC family with the crown family (TCC-1) are 8.2 and 8.5 kcal/mol, respectively.A new two-step synthesis of oxocane and its 2,2,7,7-d4 analogue is reported, the latter allowing unequivocal assignment of chemical shifts. 13C NMR spectra of oxocane between 138 and 290 K show BC-family/crown-family inter-conversion in the vicinity of 215 K (ΔG(excit.) = 10.0 +/- 0.3 kcal/mol), with the crown family comprising 4percent of the equilibrium at 174 K (ΔG0 = 1.1 +/- 0.1 kcal/mol).The 1H and 13C LIS induced by Yb(fod)3 on oxocane agree well with BC-3 and BC-7 being the predominant conformers at room temperature but do not acceptably fit a BC-1 structure.Thus, all available data from calculation and experiment are in accord with BC-3 being the favored conformation of oxocane.
A Polyketide Cyclase That Forms Medium-Ring Lactones
Gao, De-Wei,Jamieson, Cooper S.,Wang, Gaoqian,Yan, Yan,Zhou, Jiahai,Houk,Tang, Yi
, p. 80 - 84 (2021/01/13)
Medium-ring lactones are synthetically challenging due to unfavorable energetics involved in cyclization. We have discovered a thioesterase enzyme DcsB, from the decarestrictine C1 (1) biosynthetic pathway, that efficiently performs medium-ring lactonizations. DcsB shows broad substrate promiscuity toward linear substrates that vary in lengths and substituents, and is a potential biocatalyst for lactonization. X-ray crystal structure and computational analyses provide insights into the molecular basis of catalysis.
Green Oxidation of Ketones to Lactones with Oxone in Water
Bertolini, Valentina,Appiani, Rebecca,Pallavicini, Marco,Bolchi, Cristiano
, p. 15712 - 15716 (2021/11/01)
Cyclic ketones were quickly and quantitatively converted to 5-, 6-, and 7-membered lactones, very important synthons, by treatment with Oxone, a cheap, stable, and nonpollutant oxidizing reagent, in 1 M NaH2PO4/Na2HPO4 water solution (pH 7). Under such simple and green conditions, no hydroxyacid was formed, thus making the adoption of more complex and non-eco-friendly procedures previously developed to avoid lactone hydrolysis unnecessary. With some changes, the method was successfully applied also to water-insoluble ketones such as adamantanone, acetophenone, 2-indanone, and the challenging cycloheptanone.
LIPID PRODRUGS OF GLUCOCORTICOIDS AND USES THEREOF
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Paragraph 00544; 00545, (2020/09/12)
The present invention provides lymphatic system-directing lipid prodrugs, pharmaceutical compositions thereof, methods of producing such prodrugs and compositions, and methods of improving the bioavailability or other properties of a therapeutic agent that comprises part of the lipid prodrug. The present invention also provides methods of treating a disease, disorder, or condition such as those disclosed herein, comprising administering to a patient in need thereof a disclosed lipid prodrug or a pharmaceutical composition thereof.