Phosphorus reduction, nitro compounds

Reduction of nitro compounds with yellow phosphorus [55] (Eq. 53). 

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. ... 

When the previous acid is evaporated on the water-bath with seven parts of fuming nitric acid, nitration takes place m the meinitro-acid forms pale yellow needles, M.pt. 174° C., and is less soluble in water than the corresponding para-compound. The barium and calcium salts are yellow, microcrystalline powders. Reduction of the mtro-acid yields the amino-acid as brownish needles, softening at 280° to 300° C. and decomposing at higher temperatures the barium and calcium salts are reddish-brown powders. o-Carboxyphenylphosphinic acid,... 

An interesting topological effect is the increased terminal chlorination of fatty acids when they are adsorbed and aligned on alumina Silicon disulfide and particularly boron sulfide have been used with advantage instead of phosphorus pentasulfide to replace carbonyl oxygen by sulfur The addition of sulfur monochloride to olefins followed by reduction of the adduct with sodium sulfide provides a convenient inexpensive route to a large number of episulfides A direct conversion of ar. nitro compounds to isothiocyanates has been reported Sec. phosphines add easily to olefins under UV-irradiation Advances in peptide synthesis include the use of acyloxyphospho-nium salts prepared with hexamethylphosphoramide a simple synthesis with triphenyl phosphite , and the use 4-picolyl esters at the... 

Starting with cuminal, nitro-cuminal was prepared, the nitro group entering the para position, meta to the aldehyde group. This compound - when treated with phosphorus pentachloride was converted into nitro-cymyline chloride, which on reduction with zinc and hydrochloric acid... 

Dihydroxy-5,6-diphenylpyrazine refluxed with aqueous hydrazine hydrate gave 2-hydrazino-3-hydroxy-5,6-diphenylpyrazine, which was also obtained by heating 2-hydroxy-3-nitro-5,6-diphenylpyrazine with aqueous hydrazine (1124). Distillation of the compound claimed by Japp and Knox (317) to be 3-hydroxy-2,5-diphenylpyrazine (317, cf. 282) with zinc dust produced 2,5-diphenylpyrazine (317) reduction of the former with hydriodic acid and red phosphorus at 200 for 6 hours gave what was regarded as 2,5-diphenyl-3,4-dihydropyrazine (317). 

It is intriguing to consider the mode of reduction that elemental phosphorus might take if, in the absence or presence of iodine, it is effective in reducing nitro and nitroso compounds (Eq. 3). What type of reduced nitrogen compounds would form Also, this might be an elegant method for reducing the N-oxldes of heterocyclic compounds. These N-oxides are often formed in heterocylic compounds, such as pyridine, to alter the orientation of substitution. 

J. I. G. Cadogan, Reduction of Nitro-und Nitroso-compounds by Tervalent Phosphorus Reagents Quart. Rev. 

Alkylation and reduction of the nitro group to the amino has been observed in the methyl ether of 4-hydroxy-nitronaphthalene. Cydohexylmagnesium chloride in tetrahydrofuran added dropwise but rapidly at 0°C to the compound in tetrahydrofuran followed successively by tert-butanol and phosphorus trichloride in tetrahydrofuran with completion of the reactton at ambient temperarure during 3 hours gave after acidification with hydrochloric acid,... 

Parathion, paraoxon and EPN are subject to reduction of the aromatic nitro group to an amino group [159] by mammalian, avian and piscine tissues [160], Paraoxon is the most readily reduced of the three compounds, EPN the least. Paraoxon metabolism to aminoparaoxon is the route of inactivation by rat, chicken and guinea-pig livers in vitro [160]. However, enzymatic hydrolysis of the phosphorus-nitrophenyl linkage of the oxo-analogues appears to he a major pathway of detoxication in manunals [142, 161, 162] but bovine rumen fluid is capable of reducing parathion and EPN to their... 

Note 4. Reduction of nitrogen compounds prior to Kjeldahl digestion. Nitro, nitroso and azo compounds, also hydrazones, oximes and some heterocyclic compounds are not quantitatively digested by the catalysts A, B or C shown in Table 2.8. If compounds of these types are being analysed either add 0.5 g pure sucrose (or glucose) to the mixture of catalyst A or B, sulfuric acid and a suitable weight of sample (or carry out a preliminary reduction of the sample with hydriodic acid and red phosphorus as described next.)... 

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