[CH3:1][C:2]1[CH:10]=[C:6]([C:7]([OH:9])=[O:8])[C:5](N)=[CH:4][CH:3]=1.Cl.N([O-])=O.[Na+].[I-:17].[K+].S([O-])([O-])(=O)=S.[Na+].[Na+]>O>[I:17][C:5]1[CH:4]=[CH:3][C:2]([CH3:1])=[CH:10][C:6]=1[C:7]([OH:9])=[O:8]20 G. of 5-methyl-anthranilic acid are suspended in 200 ml. of 3-N hydrochloric acid at 0° C. A solution of 10 g. of sodium nitrite and 20 ml. of water is added dropwise thereto with stirring and the mixture is further stirred for 25 minutes at 0° C. A solution of 26.5 g. of potassium iodide, 30 ml. of 3-N hydrochloric acid and 30 ml. of water is then added dropwise at 5°-10° C. The mixture is stirred for an additional 30 minutes at room temperature and for 2 hours at reflux. The mixture is cooled and sodium thiosulfate is added until the solution is yellow (5 g.). The crystalline 2-iodo-5-methyl-benzoic acid obtained is removed by filtration under vacuum and washed neutral with water. The crude acid is dissolved in ether, washed well with sodium thiosulfate solution and water, dried over sodium sulfate and evaporated, and there are obtained light-brown crystals having a melting point of 100°-112° C.
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