78018-54-9Relevant academic research and scientific papers
SYNTHETIC APPLICATIONS OF CHROMIUM(VI) REAGENTS IN COMBINATION WITH CHLOROTRIMETHYLSILANE
Cossio, Fernando P.,Aizpurua, Jesus M.,Palomo, Claudio
, p. 225 - 231 (2007/10/02)
The synthetic utility of chromium(VI) reagents together with chlorotrimethylsilane, as new oxidizing systems, is described.Pyridinium dichromate (PDC) in combination with chlorotrimethylsilane oxidizes tert-butyldimethylsilyl ethers in good to excellent yields.Trimethylsilyl chlorochromate, a new chromium(VI) reagent, also was found efficient for this oxidative-deprotection method.These reagents were applied to the oxidation of some N-(2-phenyl-2-hydroxyethyl)azetidin-2-ones as well as N-(2-phenyl-2-trialkylsiloxy)azetidin-2-ones into their corresponding carbonyl compounds, key intermediates for N-unsubstituted β-lactams.Oxidation of hydroquinones and protected trialkylsilyl hydroquinones was also described.Protection of hydroquinones by means of the tert-butyldimethylsilyl group was achieved by using the readily available tert-butyldimethylchlorosilane (TBDMCS) and 1,8-diazabicycloundec-7-ene (DBU) as base, which avoids the use of sophisticated and (or) sensitive reagents.
Pyridinium Chlorochromate Releases Quinones from Hydroquinone Silyl Ethers.
Willis, John P.,Gogins, Kitty A.,Miller, Larry L.
, p. 3215 - 3218 (2007/10/02)
The pyridinium chlorochromate oxidation of six bis(trimethylsilyl) and six bis(tert-butyldimethylsilyl) ethers of p-hydroquinones at room temperature in methylene chloride solution gave the corresponding quinones in 60-90percent yield.The bis(trimethylsilyl) ethers were slightly more reactive than the bis(tert-butyldimethylsilyl) ethers.High oxidation efficiency was indicated by a 1:1 molar stoichiometry; however, more convenient reaction times were obtained at a 2:1 molar ratio of pyridinium chlorochromate (PCC) to hydroquinone silyl ether.The mechanism is discussed based upon comparisons of relative reaction rates with electrochemical oxidation potentials.
