Glucose nitro compounds

Azoxy compounds can be obtained from nitro compounds with certain reducing agents, notably sodium arsenite, sodium ethoxide, NaTeH, NaBH4—PhTeTePh, and glucose. The most probable mechanism with most reagents is that one molecule of nitro compound is reduced to a nitroso compound and another to a hydroxylamine 119-42), and these combine (12-51). The combination step is rapid compared to the reduction process. Nitroso compounds can be reduced to azoxy compounds with triethyl phosphite or triphenylphosphine or with an alkaline aqueous solution of an alcohol. ... 

However, this multistep procedure is experimentally complex. A simpler variation described in 199127 consists of the reaction of an aldehyde and a nitro compound in the presence of triethylamine, TBAF and tert-butyl-dimethylsilyl chloride. Under these conditions, nitro sugars are obtained in good yieds and higher diastereoselectivities than those afforded by the standard conditions. This procedure was used in several synthesis of 2-nitro-2-deoxyaldoses, as for the condensation of l,l-diethoxy-2-nitroethane and l,2 3,4-di-0-isopropylidene-a-D-galacto-hexodialdo-l,5-piranose.28 More recently, it was applied to the addition of ethyl nitroacetate to the D-glucose derived aldehyde 18, to give nitro sugar derivatives 26, key precursors of polysubstituted cyclohexane a-amino acids (Scheme 10).29... 

Nitropropanoyl esters of glucose from the roots of Lotus pendunculatus Cav. were determined by analysis of nitrate released on alkaline hydrolysis. This method was validated for quantitation of both total nitro compounds in ethanolic extracts and for individual components from TLC separations557. 

The reduction of aromatic nitro compounds with glucose and other carbohydrates in an alkaline medium has been a much neglected reaction procedure (see, for example, Bigelow and Palmer [46, Note 7]). The reaction has much to... 

Azoxybenzene is readily prepared by reduction of nitrobenzene in an alkaline medium with a variety of mild reducing agents. Reducing sugars have been used successfully for the reduction of substituted nitro compounds to the corresponding azoxyarenes33 and the use of D-glucose for the reduction of nitrobenzene is illustrated in Expt 6.89. 

Reduction by glucose and alkali is used only in a very special field the reduction of nitro compounds to azoxy and azo compounds. 

An interesting reduction of aromatic nitro compounds which uses glucose in an alkaline medium (equation 7) has received little attention. The advantages of this reaction include high yields, rapid rate and ease of product isolation from oxidation by-products. Other reagents which bring about the reduction of nitroanenes to azoxy compounds include potassium borohydride, sodium arsenate, phosphine and yellow phosphorus. Electrolytic methods have also been utilized. ... 

This acid is formed in 62 per cent, yield by reducing the corresponding nitro-compound with glucose and alkali. Its mdting-point is over 800° C. it forms amorphous calcium and magnesium salts. The acetyl derivative crystallises from water in stout plates, melting with decomposition at 205° C. it forms a microcrystalline barium salt and an amorphous calcium salt. 

Numerous studies have shown that low hydrogen overpotential electrically conducting catalysts (e.g., Raney nickel, platinum and palladium on carbon powder, and Devarda copper) can be used to electrocatalyticaUy hydrogenate a variety of organic compounds including benzene and multiring aromatic compounds, phenol, ketones, nitro compounds, dinitriles, and glucose [45, 46, 54, 55, 67-71]. These reactions have been carried out in both batch and semicontinuous flow reactors in most cases, the reaction products were similar to those obtained from a traditional chemical catalytic scheme at elevated temperatures and pressures. 

In individual cases nitro compounds are reduced to azo compounds by glucose in aqueous or alcoholic alkali.337 Tin(n) chloride,338 alkali sulfides,339 and sodium amalgam386 have been used for the same reduction. 

Ethylphenol has been isolated from the oleoresin of Picea abies (94). Notably, nitro compounds have also been found, namely l-nitro-2-phenylethane in wood and bark of Ocotea pretiosa and Aniba canelilla (65), and thalictoside (19) and its glucose 6-caffeoate in the bark of Parabenzoin praecox (157). A glucoside, salidroside, of 4-hydroxy-hydroxyethylbenzene has been isolated from the bark of Salix triandra (169). 

A large number of organic compounds, including aldehydes, ketones, lactones, carboxylic acids, chlorides and anhydrides, esters, amides, anilides and alcohols, ketals, epoxides, nitro compounds, glucose, ascorbic acid, and some ethers, have been analyzed by Dahn et al. (1959)... 

Aliphatic fluorodenitration has also been applied to mononitro compounds, specifically to an a-nitroepoxide Thus, l,2-anhydro-3 4 5,6-di-O isopropyli dene-1-C-nitro D mannitol and labeled potassium bifluonde give 2-deoxy-2-fluo-ro-3,4 5,6-di-O-isopropylidene aldehydo D glucose [J03, 104] (equation 30)... 

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