2-Nitroacetophenone, reduction

Formic acid is a good reducing agent in the presence of Pd on carbon as a catalyst. Aromatic nitro compounds are reduced to aniline with formic acid[100]. Selective reduction of one nitro group in 2,4-dinitrotoluene (112) with triethylammonium formate is possible[101]. o-Nitroacetophenone (113) is first reduced to o-aminoacetophenone, then to o-ethylaniline when an excess of formate is used[102]. Ammonium and potassium formate are also used for the reduction of aliphatic and aromatic nitro compounds. Pd on carbon is a good catalyst[103,104]. NaBH4 is also used for the Pd-catalyzed reduction of nitro compounds 105]. However, the ,/)-unsaturated nitroalkene 114 is partially reduced to the oxime 115 with ammonium formate[106]... 

CINNOLINES AND QUINOXALINES Replacement of a methine in oxolinic acid (46) by nitrogen is apparently consistent with retention of antibacterial activity. One approach begins with reduction of nitroacetophenone 144 to afford the corresponding aminoketone (145). Treatment of this intermediate with nitrous acid leads to the diazonium salt the diazonium group condenses with the ketone methylene group (as its enol form) to lead to the cyclized product, cinnoline 147. Bromination proceeds at the position adjacent the enol grouping (148) ... 

The photoreduction of aromatic nitro compounds to the amino compounds can be carried out on the surface of semiconductor particles such as titanium oxide1 with H-atom donors (equation 1). At a shorter duration of the photoinduced reduction of p-nitroacetophenone, the hydroxylamine intermediate can be obtained in about 30% yield. The reaction mechanism proposed is based on the photoexcitation of TiC>2 to generate an electron and a positive hole (equations 2 and 3). Aliphatic nitro compounds such as 12-nitrododecanoic acid can be reduced to 12-amino dodecanoic acid in 90% yield by this method. 

Preferential reduction of a nitro group in the presence of a carbonyl group in 4-nitroacetophenone ISD, intramolecular rearrangements of o-nitro-benzanilides 32) intramolecular cyclizations of o-nitro-ferf-anilines to benzimidazol-1-oxides 153,154) cyclizations of acylated 2-nitrodiphenylamines to phenazine-l-oxides i ), intramolecular additions of nitro groups to double bonds 156) remarkably ef-... 

The reduction of a dinitro ketone to an azo ketone is best achieved with glucose. 2,2 -Dinitrobenzophenone treated with glucose in methanolic sodium hydroxide at 60° afforded 82% of dibenzo[c,f [i 2]diazepin-l 1-one whereas lithium aluminum hydride yielded 24% of bis(o-nitrophenyl)methanol [575], Conversion of aromatic nitro ketones with a nitro group in the ring into amino ketones has been achieved by means of stannous chloride, which reduced 4-chloro-3-nitroacetophenone to 3-amino-4-chloroacetophenone in 91% yield [178]. A more dependable reagent for this purpose proved to be iron which, in acidic medium, reduced m-nitroacetophenone to m-aminoacetophenone in 80% yield and o-nitrobenzophenone to o-aminobenzophenone in 89% yield (stannous chloride was unsuccessful in the latter case) [903]. Iron has also been used for the reduction of o-nitrochalcone, 3-(o-nitrophenyl)-l-phenyl-2-propen-l-one, to 3-(o-aminophenyl)-l-phenyl-2-propen-l-one in 80% yield [555]. 

In alkaline-alcoholic solution Elbs and Wogrinz 2 obtained m-azoxy- and m-azoacetophenone from m-nitroacetophenone. The reduction to the hydrazophase was only partially successful. 

A solution of 295 g. (1.79 moles) of m-nitroacetophenone [Org. Syntheses Coll. Vol. 2, 434 (1943)] in 1.1 1. of absolute ethanol is shaken with 1.5 tablespoons of Raney nickel catalyst [Org. Syntheses, 21, 15 (1940)] at 50° under an initial hydrogen pressure of 1950 lb. After uptake of hydrogen has ceased, the solvent is evaporated and the residue triturated with 400 ml. of a mixture of cold water and excess concentrated hydrochloric acid. The undissolved portion after filtration is treated again with hydrochloric acid. The combined insoluble portions from four reduction batches are washed with water until free from acid and dried (170 g.) and subjected to reduction as before. The combined hydrochloric acid solutions are treated with solid sodium carbonate with stirring until the solution is alkaline, and the precipitated m-aminoacetophenone is removed by filtration. 

The reduction of o- and />-nitrotoluene and /7-ethylnitrobenzene in DMF in the presence of dioxygen to o- and />nitrobenzoic acid and / -nitroacetophenone plus - p-nitrophenyl)ethanol, respectively, has been suggested [128] to proceed via a proton or hydrogen atom abstraction from the side chain followed by reaction of this species with superoxide ion and/or dioxygen to the isolated products. 

The chemoselective reduction of nitro and carbonyl functions with /-PrOH/ KOH over nickel-stabilized zirconia has recently been reported by Upadhya et al. [10]. This catalytic system selectively reduced 4-nitroacetophenone and... 

Anthranil and its 3-methyl derivative are obtained by electrolytic reduction of o-nitrobenzaldehyde and o-nitroacetophenone, respectively.133 In each case the anthranils are characterized as their HgCl2 complexes. 

The undermentioned reductions may be carried out by simple adaptations to the procedures chloral to trichloroethjd alcohol i-nitroacetophenone of a-methyl-3-nitrobenzyl alcohol and o-nitrobenzaldehyde to o-nitrobenzyl alcohol. 

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