A. m-Nitrobenzoyl chloride. In a 1-l. round-bottomed flask are placed 200 g. (1.2 moles) of crude m-nitrobenzoic acid² and 500 g. (300 ml., 4.2 moles) of thionyl choride (Note 1). The flask is fitted (ground-glass joint) with a reflux condenser carrying a calcium chloride drying tube leading to a gas-absorption trap³ and is heated on a steam bath for 3 hours. The condenser is then set for downward distillation, and as much of the excess thionyl chloride as possible is distilled at the temperature of the steam bath. The residue is transferred to a 250-ml. Claisen flask and distilled at reduced pressure (water pump), b.p. 153–154° /12 mm. (Note 2). The yield is 200–217 g. (90–98%), m.p. 33°.

B. m-Nitrobenzazide. In a 2-l. round-bottomed flask fitted with an efficient mechanical stirrer is placed a solution of 78 g. (1.2 moles) of commercial sodium azide in 500 ml. of water (Note 3). The flask is surrounded by a water bath kept at 20–25°. The stirrer is started, and over a period of about 1 hour a solution of 185.5 g. (1 mole) of m-nitrobenzoyl chloride in 300 ml. of acetone (previously dried over anhydrous potassium carbonate) is added from a dropping funnel. m-Nitrobenzazide separates at once as a white precipitate. Stirring is continued for 30 minutes after the addition is complete; then 500 ml. of water is added and the reaction mixture stirred for an additional 30 minutes. The azide is separated on a suction filter, washed with water, and dried in the air. The yield of crude product, m.p. 68°, is 189 g. (98%) (Note 4). It may be recrystallized from a mixture of equal parts of benzene and ligroin (b.p. 100–140°), when the temperature is kept below 50° (Note 5). The product thus obtained consists of almost colorless crystals, m.p. 68–69° (Note 6), the recovery being 80–90% (Note 7).