M-Nitroacetophenone

Since the solubility curve is so flat in the vicinity of room temperature it is not necessary to cool very low before filtering. The difference between 20° and io° amounts to only 1 g. per 100 cc. of solution. The solubility of m-nitroacetophenone in 96 per cent alcohol is as follows ... 

This new type of photoredox reaction of p- and m-nitro-substitutcd aromatic derivatives is not observed in organic solvents, and is99,100 extended to m-nitrobenzyl derivatives 162 containing alcohol, alkyl ether, ester or amine functions these compounds undergo photooxidation to produce m-nitrobenzaldehyde (or m-nitroacetophenone) as the major isolable product100 (equation 79). 

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]. 

Thermometer T should not touch the bottom of flask J. m-Nitroacetophenone (10, 74) ... 

The acetyl group is attached to the ring by Friedel-Crafts acylation. It is a meta director, and its nitration gives the proper orientation of substituents. The order of the first two steps cannot be reversed, because Friedel-Crafts acylation of nitrobenzene is not possible (Section 12.16). Once prepared, m-nitroacetophenone can be reduced to m-nitroaniline by any of a number of reagents. Indeed, all three reducing combinations described in the text have been employed for this transformation. 

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. 

The nitration of acetophenone has been extensively studied. It is carried out at a low temperature (5° to -20°) by the action of nitric and sulfuric acids and gives m-nitroacetophenone (55 83%) and smaller amounts of o-nitroacetophenone. Under similar conditions, benzalde-hyde is converted to m-nitrohenzaldehyde (84%). If nitration is performed on benzaldehyde diacetate, C(HsCH(CXZCXZH3)2, with subsequent hydrolysis, p-nitrobenzaldehyde (73%) is obtained furthermore, a slight modification of this procedure causes the formation of mainly the ortho isomer (43%). ... 

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. 

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