C(Cl)(=O)C(Cl)=O.[N+:7]([C:10]1[CH:18]=[CH:17][CH:16]=[C:12]([C:13](O)=[O:14])[C:11]=1[OH:19])([O-:9])=[O:8].[C]=O.[CH3:22][NH:23][CH3:24]>ClCCl.CN(C)C=O.O1CCCC1>[OH:19][C:11]1[C:10]([N+:7]([O-:9])=[O:8])=[CH:18][CH:17]=[CH:16][C:12]=1[C:13]([N:23]([CH3:24])[CH3:22])=[O:14]
42.9 ml (0.50 mol, 3 eq) of oxalyl chloride were added dropwise to a suspension of 30 g (0.16 mol, 1 eq) of 3-nitrosalicylic acid in 1200 ml of dichloromethane. 30 drops of N,N-dimethylformamide were added (large amount of gas given off, adaptation of a system for trapping toxic carbon monoxide vapors). The reaction medium was stirred at ambient temperature for 24 hours. The reaction medium was cooled to 0-5° C. and then 246 ml (0.49 mol, 3 eq) of a 2 N solution of dimethylamine in tetrahydrofuran were added. The reaction medium was stirred at ambient temperature for 2 days. The reaction medium was concentrated to dryness and the residue was dissolved in 300 ml of 1 N sodium hydroxide. The aqueous solution (red) was extracted 3 times with 300 ml of dichloromethane. The aqueous phase was cooled in a water-ice bath, and the pH was adjusted to 2 with approximately 50 ml of 6 N hydrochloric acid. The mixture (which had become yellow) was extracted 3 times with 300 ml of dichloromethane. The organic phases were combined, washed twice with 250 ml of water and then once with 250 ml of a saturated sodium chloride solution, dried over anhydrous magnesium sulfate and evaporated. 33.5 g of 2-hydroxy-N,N-dimethyl-3-nitrobenzamide were obtained in the form of a cottony yellow solid. Yield=97%.
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