82922-13-2Relevant articles and documents
Transfer Hydrogenation of Cyclopamine Analogs
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Page/Page column 50, (2012/03/27)
Provided herein is a process for the transfer-hydrogenation of ketone analogs of members of the jervine type of Veratrum alkaloids, such as cyclopamine. Also provided herein are novel ruthenium transfer-hydrogenation catalysts.
N-Alkyl-5,5-dimethyl-2-oxomorpholin-3-yl radicals. Characterization and reaction with molecular oxygen
Benson Jr., Okster,Demirdji, Samuel H.,Haltiwanger, R. Curtis,Koch, Tad H.
, p. 8879 - 8886 (2007/10/02)
The synthesis of bi(4,5,5-trimethyl-2-oxomorpholin-3-yl) (TM-3′ dimer), bi(5,5-dimethyl-4-cthyl-2-oxomorpholin-3-yl) (DEM-3 dimer), and bi(5,5-dimethyl-4-isopropyl-2-oxomorpholin-3-yl) (DIM-3 dimer) by one-electron oxidation of 4,5,5-trimethyl-2-oxomorpholine (8), 5,5-dimethyl-4-ethyl-2-oxomorpholine (9), and 5,5-dimethyl-4-isopropyl-2-oxomorpholine (10), respectively, with photochemically generated rert-butoxyl radical is described. dl-TM-3′ dimer, meso-DEM-3 dimer, and meso-DIM-3 dimer were characterized from spectra and by X-ray crystallography. In solution the radical dimers existed in equilibrium with the captodatively substituted radicals, 4,5,5-trimethyl-2-oxomorpholin-3-yl (TM-3′), 5,5-dimethyl-4-ethyl-2-oxomorpholin-3-yl (DEM-3), and 5,5-dimethyl-4-isopropyl-2-oxomorpholin-3-yl (DIM-3), respectively, as indicated by EPR spectroscopy. The activation parameters for bond homolysis in ethanol solvent were measured by oxidatively trapping the radicals with diphenylpicrylhydrazyl (DPPH). The half-lives for bond homolysis vary by S orders of magnitude at 25°C with a value of only 2.3 s for DIM-3 dimer. DIM-3 dimer reacted quantitatively with molecular oxygen to form a mixture of meso- and dl-bis(5,5-dimethyl-4-isopropyl-2-oxomorpholin-3-yl) peroxides (DIM-3 peroxides), which were isolated and characterized spectroscopically and analytically. At ambient temperature the peroxides fragmented by C-O bond homolysis to release the DIM-3 radical as indicated by EPR spectroscopy and were solvolyzed by protic solvent with release of hydrogen peroxide. The solvolysis was reversed by evaporation of the protic solvent, which restored most of the DIM-3 peroxides. The peroxides also slowly fragmented irreversibly to 5,5-dimethyl-3-hydroxy-4-isopropyl-2-oxomorpholine (21) and 5,5-dimethyl-2,3-dioxo-4-isopropylmorpholine (23) in polar aprotic solvent.
