3-Nitroacetophenone

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]... 

Table 16 Condensation of 1,4-Dilithio Oximes and 2-Nitroacetophenone Oximes with Various Electrophiles...

Aldehydes react with a-nitroacetophenone in refluxing toluene to generate a 3-acetyl-2-isoxazoline (78USP4092327), while a-nitroacetophenone oxides react with alkenes to provide 2-isoxazolines (Scheme 121) (79ZOR735, 79ZOR2408, 80CPB479>. 

O-Bromo-4-nitroacetophenone [99-81-0] M 244.1, m 98°. Crystd from "CgHs-pet ether. 

Nitroacetophenone 100-19-6) M 165.2, m 80-81", b 145-152"/760mm. Crystd from EtOH or aqueous EtOH. 

The reaction of o-diamines with w-nitroacetophenone in the presence of sodium dithionite furnishes 2-phenylquinoxalines, and reaction of o-phenylenediamine with p-N0..C,-.H4C0CH2X02 similarly gives 2- (4 -nitrophenyl) quinoxaline ... 

Ketones such as p-nitroacetophenone 1877 are reduced by dimethylchlorosilane Me2HSiCl 882/In(OH)3, in high yields, to chloro compounds such as 1878 [90] (Scheme 12.26). 

The catalyst used throughout this study was a 1% w/w palladium on graphite powder (S.A. 10 mV ) supplied by Johnson Matthey. 2-nitroacetophenone, 3-nitroacetophenone and 4-nitroacetophenone (all Aldrich >99 %) were used without further purification. No significant impurities were detected by GC. Gases (BOG, >99.99 %) were used as received. 

The hydrogenation of the three nitroacetophenone isomers was compared at 3 barg and 323 K. The results are shown in Table 8.1, where it can be seen that the 3-isomer is by far the most reactive with little difference between the 2- and 4-isomers. 

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