Nitroxide chemistry. Part I. Reactions of bistrifluoromethyl nitroxide with acetylene, 3,3,3-trifluoropropyne, perfluoropropyne, perfluorobut-2-yne, perfluorodiphenylacetylene, and glyoxal

Abstract

In addition to perfluoro-(2,4-dimethyl-3-oxa-2,4-diazapentane) the following products were formed from reactions between bistrifluoromethyl nitroxide and the acetylenes named in parentheses: perfluoro-[3,3-bis-(dimethylamino-oxy)butan-2-one], perfluoro-(3-dimethylamino-3-dimethylamino-oxybutan-2-one), and perfluorobiacetyl (from perfluorobut-2-yne); perfluorobenzil (from perfluorodiphenylacetylene); perfluoro-[2,2-bis(dimethylamino-oxy)propanoyl] fluoride, perfluoro-(2-dimethylamino-2-dimethylamino-oxypropanoyl) fluoride, and perfluoropyruvoyl fluoride (from perfluoropropyne); NN-bistrifluoromethylhydroxylamine and bis-(bistrifluoromethylamino-oxy)bistrifluoromethylamino-oxycarbonylmethane (from acetylene); and 3,3-bis-(bistrifluoromethylamino-oxy)-1,1,1-trifluoropropan-2-one and 3-bistrifluoromethylamino-3-bistrifluoromethylamino-oxy-1,1,1-trifluoropropan-2-one (from 1,1,1-trifluoropropyne). Possible mechanisms for these conversions are discussed. A thermal reaction of perfluorobut-2-yne with perfluoro-(2,4-dimethyl-3-oxa-2,4-diazapentane) gave perfluoro-(3-dimethylamino-3-dimethylamino-oxybutan-2-one).

Treatment of bistrifluoromethyl nitroxide with glyoxal gave 1,2-bis(bistrifluoromethylamino-oxy)glyoxal, which was hydrolysed to oxalic acid and bistrifluoromethylhydroxylamine. Hydrolysis of perfluoro-[3,3-bis-(dimethylamino-oxy)butan-2-one] with aqueous sodium hydroxide gave trifluoroacetic acid.