Hydrogen Bromide → 1-Bromo-2,3-dichloro-6-nitrobenzene

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Reaction Conditions

Reaction Steps

Substituted nitrobenzenes, not hitherto described in the chemical literature, used in the preparation of substituted anilines as hereinbefore described in Reference Example 2, were prepared as follows: (a) 2,3-Dichloro-6-nitroaniline [29 g; prepared by a modification (reaction at 125° C.) of the procedure described by Beilstein and Kurbatow, Ann., 192, 235 (1878)] was dissolved with stirring at 55°-60° C. in glacial acetic acid (350 ml). A solution of sodium nitrite (11 g) in concentrated sulphuric acid (80 ml) was then added to the solution thus obtained with stirring over 15 minutes at a temperature of 55°-60° C. maintained by intermittent cooling with water. The red solution obtained was cooled to 15° C. and poured, with stirring, into a solution of cuprous bromide (20 g) in concentrated hydrobromic acid (200 ml) and ice (500 g). The mixture was allowed to attain laboratory temperature, heated for one hour at 60° C. and then steam-distilled. The distillate obtained was extracted with diethyl ether (6×500 ml). The combined ethereal extracts were washed successively with aqueous sodium hydroxide solution (2N; 3×750 ml and water (2×500 ml), dried over anhydrous sodium sulphate and filtered. The filtrate was evaporated to dryness to give a yellow powder, which was then crystallised from hexane (125 ml) to give 2-bromo-3,4-dichloronitrobenzene (26.7 g), m.p. 73° C., in the form of yellow crystals.

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