Bis-N-oxide

Oxidation of 2,3-dimethylquinoxaline (from phenylenediamine and diacetyl) with either peracids or hydrogen peroxide in acetic acid gives the 1,4-dioxide (162). Treatment of this bis-N-oxide with selenium dioxide leads to oxidation of one of the methyl groups to the methyl carbinol and formation of... 

To the best of the author s knowledge, the only isolated diaza analog of o-benzoquinone is bis-N-oxide 79 and its derivatives. Compound 79 was isolated as orange-colored crystals from a reaction of tetraketo derivative 78 with dinitrogen tetroxide (76TL1703 77AP264). 

Methyl trichlorosilyl ketene acetal reacts with aromatic and aliphatic ketones (the former enantioselectively), using chiral pyridine bis-N-oxide catalysts.134 Computations and an X-ray crystal structure of a catalyst-SiCU complex have helped to elucidate the mechanism. 

The A -oxidation of diazafluorenes and -fluorenones has been studied by Mlochowski and coworkers <79CJC1506>. The 1,8- and 2,5-diazafluorenones yielded bis N-oxides with H202/acetic acid whereas the 1,5- and 4,5 isomers gave tars. H202/Na2W05 proved to be a milder reagent and yielded oxides of all isomers. Because of the readily oxidized 9-position, diazafluorenes yielded only the N-oxides of the corresponding fluorenones. 

Although addition of the trichlorosilyl enolate of methyl acetate to aldehydes is accelerated by a Lewis base catalyst, poor enantioselectivity is observed for the asymmetric version using 79, because of competition by the uncatalyzed achiral process (Scheme 10.30 in Section 10.2.1.4) [95]. Denmark et al. recently demonstrated that reactive silyl enolates are valuable for asymmetric addition to ketones (Scheme 10.67) [174]. The use of bis-N-oxide 80 as catalyst achieves high enantioselectivity in the reaction with aromatic ketones. 

The two possible mono N-oxides of retamine, and the bis N-oxide, have been prepared by the perhydrol oxidation of retamine. In the mono iV-oxide-C (17) ring c is thought to have the boat conformation, and the molecule has a trans C-D ring-junction, since it exhibits Bohlmann bands in its i.r. spectrum. The bis A -oxide (18) also has a boat-shaped ring c and a trans c-d ring-junction, since it can be prepared by further oxidation of mono N-oxide-C. 

Giorgi-Renault and co-workers introduced a new method to prepare phenazine bis-N-oxides <01SC2329>. Oxidation of 229 with excess NaClO in presence of KOH gave 230 in excellent yield, followed by esterification to afford 231. Then, compound 233 was prepared by condensation of 231 and enamine 232. 5,10-Dioxyphenazine-2-carboxylic acid 236 was prepared by a two-step aromatization of precursor 233. First 233 was dibrominated in presence of MBS and a catalytic amount of benzoyl peroxide, then subsequent dehydrobromination 234 by KOBu afforded aromatized product 235. Finally, saponification of 235 gave the final product 236 in good yield. 

Synonyms Bis (2-hydroxyethyl) lauramine oxide Dihydroxyethyl lauryl amine oxide Dodecylamine, N,N-bis (2-hydroxethyl)-, N-oxide 2,2 -(Doclecylimino) bisethanol-N-oxide Ethanol, 2,2 -dodecylimino) bis-, N-oxide Classification Tertiary amine oxide Uses Surfactant in cosmetics Trade Name Synonyms Softamin LD [Toho Chem. Ind. http //www.toho-chem.co.jp]... 

Synonyms Bis (2-hydroxyethyl) stearylamine oxide Ethanol, 2,2 -(octadecylimino) bis-, N-oxide 2,2 -(Octadecylimino) bisethanol, N-oxide... 

Terpene-derived bis-N-oxide 21.22 represent the most recent addition to the successful catalyst series. The catalyst was shown to be particularly efficient in the allylation and crotylation of aromatic and a,p-unsaturated aldehydes (<99% enantiomeric excess at —60°C), however, with aliphatic aldehydes the selectivity dropped to 50% ee. It is noteworthy that 21.22 was synthesised in four easy steps from inexpensive (I )-myrtenal and the protocol is amendable to scaling up. In contrast, synthesis of enantiopure catalysts 21.19-21.21 requires either resolution of enantiomers or separation of diastereoisomeric mixtures, which hampers their larger-scale application. In this group of polydentate IV-oxides it is also worth mentioning terpyridine N,IV IV"-trioxide, the related bis-imidazole Af,M -dioxides and chiral dinitrones,but their efficiency was inferior to the best pyridine-type dioxides, such as 21.20-21.22. 

Cl2H23NO, 1,2,2,6,6-Pentamethyl-4-vinyl-4-piperidinol, 46B, 231 C12H24N2O2 4 H2O, 1,2-Di(N-piperidyl)ethane bis-N-oxide tetrahyd-rate, 45B, 231... 

The oxidation of l,2-bis[5 -methyl-2 -(2"-pyridyl)thiazolyl]periluorocyclo-pentene with m-CPBA involves only the nitrogen atoms of the pyridine cycle and affords the corresponding photochromic mono- 74 and bis-N-oxides 75 exhibiting photochromism both in solution and in the crystalline state [83]. 

---