29872-25-1Relevant academic research and scientific papers
Reduction of amine N-oxides by diboron reagents
Kokatla, Hari Prasad,Thomson, Paul F.,Bae, Suyeal,Doddi, Venkata Ramana,Lakshman, Mahesh K.
experimental part, p. 7842 - 7848 (2011/12/01)
Facile reduction of alkylamino-, anilino-, and pyridyl-N-oxides can be achieved via the use of diboron reagents, predominantly bis- (pinacolato)- and in some cases bis(catecholato)diboron [(pinB)2 and (catB)2, respectively]. Reductions occur upon simply mixing the amine N oxide and the diboron reagent in a suitable solvent, at a suitable temperature. Extremely fast reductions of alkylamino- and anilino-N-oxides occur, whereas pyridyl-N-oxides undergo slower reduction. The reaction is tolerant of a variety of functionalities such as hydroxyl, thiol, and cyano groups, as well as halogens. Notably, a sensitive nucleoside N-oxide has also been reduced efficiently. The different rates with which alkylamino- and pyridyl-N-oxides are reduced has been used to perform stepwise reduction of the N,N-dioxide of (S)-(-)-nicotine. Because it was observed that (pinB)2 was unaffected by the water of hydration in amine oxides, the feasibility of using water as solvent was evaluated. These reactions also proceeded exceptionally well, giving high product yields. In constrast to the reactions with (pinB)2, triethylborane reduced alkylamino-N oxides, but pyridine N-oxide did not undergo efficient reduction even at elevated temperature. Finally, the mechanism of the reductive process by (pinB)2 has been probed by 1H and 11B NMR. (Figure presented) ; 2011 American Chemical Society.
Process for the preparation of amine oxides
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Page/Page column 7, (2008/06/13)
The present invention provides a process for the preparation of amine oxide by reacting a tertiary or a secondary amine with hydrogen peroxide as an oxidant in the presence of a recyclable heterogeneous catalyst comprising a layered double hydroxide exchanged with an anion in the presence of an additive selected from the group consisting of benzonitrile, propionitrile, isoburyronitrile, benzamide and isobutyramide.
The first example of catalytic N-oxidation of tertiary amines by tungstate-exchanged Mg-Al layered double hydroxide in water: A green protocol
Choudary,Bharathi,Venkat Reddy,Lakshmi Kantam,Raghavan
, p. 1736 - 1737 (2007/10/03)
A green process, using a recyclable tungstate-exchanged Mg-A1 layered double hydroxide (LDH-WO42-) heterogenised catalyst and aqueous H2O2 oxidant in water, leads to N-oxidation of aliphatic tert-amines to amine N-oxides in quantitative yields, at a high rate at room temperature.
On the preparation of amine N-oxides by using dioxiranes
Ferrer, Marta,Sanchez-Baeza, Francisco,Messeguer, Angel
, p. 15877 - 15888 (2007/10/03)
The reaction of heterocyclic aromatic amines, anilines and tertiary amines with dimethyldioxirane (DMD) was examined. Treatment of heterocyclic aromatic amines and anilines with a slight excess of DMD at 0°C afforded the corresponding N-oxides in quantitative conversion yields. In addition, the oxidation was chemoselective in the presence of carbon-carbon double bonds. On the other hand, most of the tertiary amines assayed did afford also quantitative yields of the corresponding N. oxides, although reaction conditions, in particular regarding the amount of DMD required, depended on each substrate. Additional studies carried out on selected substrates suggested that certain N-oxides derived from tertiary amines deactivate DMD.
Silicon Polonovski Reaction. Formation and Synthetic Application of α-Siloxy Amines
Tokitoh, Norihiro,Okazaki, Renji
, p. 3291 - 3298 (2007/10/02)
A new and versatile synthetic intermediate, α-siloxy amine was prepared in situ by the base-promoted rearrangement of a siloxyammonium salt obtained by treatment of a tertiary amine N-oxide with trialkylsilyl trifluoromethanesulfonate.The best combination of the base and silylating reagent was found to be methyllithium and t-butyldimethylsilyl trifluoromethanesulfonate.The reactions of α-siloxy amines with acyl halides and haloformates gave the corresponding amides and carbamates in moderate to good yields, respectively.Treatment of α-siloxy amines with acetic acid resulted in a direct dealkylation to free secondary amines.Fluoride induced alkylation of α-siloxy amines using alkyl halides as electrophiles leading to tertiary amines was also examined and demonstrated to be a new transalkylation method of amines.
