4-Acetamido-TEMPO

Glycol oxidation. The tosic acid salt of 4-acetamido-TEMPO is a mild oxidizing agent that converts glycols to a-dicarbonyl compounds. 

Hardwood NaBr, 4-acetamido-TEMPO and NaClOj, with ultrasound 68,170 kHz, 1000 W, TEMPO-chlorite at 70°C for 2 h Shree et al. (2012)... 

The application of ionic liquids as a reaction medium for the copper-catalyzed aerobic oxidation of primary alcohols was reported recently by various groups, in attempts to recycle the relatively expensive oxidant TEMPO [150,151]. A TEMPO/CuCl-based system was employed using [bmim]PF6 (bmim = l-butyl-3-methylimodazolium) as the ionic liquid. At 65 °C a variety of allylic, benzylic, aliphatic primary and secondary alcohols were converted to the respective aldehydes or ketones, with good selectiv-ities [150]. A three-component catalytic system comprised of Cu(C104)2, dimethylaminopyridine (DMAP) and acetamido-TEMPO in the ionic liquid [bmpy]Pp6 (bmpy = l-butyl-4-methylpyridinium) was also applied for the oxidation of benzylic and allylic alcohols as well as selected primary alcohols. Possible recycling of the catalyst system for up to five runs was demonstrated, albeit with significant loss of activity and yields. No reactivity was observed with 1-phenylethanol and cyclohexanol [151]. 

An efficient and convenient methodology for the aerobic oxidation of alcohols catalysed by sol-gel trapped perruthenate and promoted by an encapsulated ionic liquid in supercritical carbon dioxide solution has been reported. The reaction is highly selective and useful for substrates otherwise difficult to oxidize.263 A four-component system consisting of acetamido-TEMPO-Cu(C104)2-TMDP-DABCO has been developed for aerobic alcohol oxidation at room temperature. The catalytic system shows excellent selectivity towards the oxidation of benzylic and allylic alcohols and is not deactivated by heteroatom-containing (S, N) compounds. The use of DMSO as the reaction medium allows the catalysts to be recycled and reused for three runs with no significant loss of catalytic activity.264... 

It should be mentioned that, due to the good solubility of acetamido-TEMPO and DMAP in [bmpy][PFg], these reagents could be recycled and reused for five runs after full extraction of the products, without any significant loss of catalytic... 

If the anomeric centre is not protected, TEMPO-mediated oxidations of monosaccharides with CI2 or Br2 yield aldaric acids, i.e. co-diacids in which the all secondary hydroxyl groups are preserved the use of the 4-acetamido derivative of TEMPO is to be preferred because of its greater stability and lower volatility. This method of making aldaric (saccharic) acids supersedes the use of nitric acid, used in Emil Fischer s classical work to make both ends of... 

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