3.5- Dinitrobenzoic acid anhydride

Cleavage of Ethers with 3,5-Dinitrobenzoic Acid Anhydride and Stannic Chloride (5)... 

The ether (0.05 ml), 3,5-dinitrobenzoic acid anhydride (0.05 g) [for the preparation see (5)], and 1 ml of a 0.5 m SnCl4 solution in benzene (prepared from 6 ml of SnCl4 and benzene to make a total volume 100 ml) are introduced into an ampoule which is then sealed and heated at 120 °C for 30 min. After cooling, the ampoule is opened and the benzenic solution is spotted directly onto a strip of chromatographic paper, where solutions of aut-enthic samples of esters of 3,5-dinitrobenzoic acid are also applied (see p. 154). Chromatography is carried out in dimethylformamide or formamide/ /hexane. For thin-layer chromatography on silica gel G the system cyclohexane-carbon tetrachloride-ethyl acetate (10 75 15) is used. 

CrOy-HiSOi. A solution of 36 g. of 3,4-dinitrotoIuene in 180 ml. of coned, sulfuric acid at 30° is stirred during slow addition of 60 g. of chromic anhydride in small portions, with cooUi to control the temperature to 45-50° after 4 hrs. the solution is poured onto ice. The yield of 3,4-dinitrobenzoic acid is 89%. ... 

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