[F:1][S:2]([F:15])([F:14])([F:13])([F:12])[C:3]1[CH:4]=[C:5]([CH:9]=[CH:10][CH:11]=1)[C:6]([OH:8])=[O:7].S(=O)(=O)(O)O.[N+:21]([O-])([OH:23])=[O:22]>>[F:1][S:2]([F:12])([F:13])([F:14])([F:15])[C:3]1[CH:4]=[C:5]([CH:9]=[C:10]([N+:21]([O-:23])=[O:22])[CH:11]=1)[C:6]([OH:8])=[O:7]3-Pentafluorosulfanylbenzoic acid (3.0 g) was dissolved in fuming nitric acid (20 ml) and stirred at RT with exclusion of moisture. Concentrated sulfuric acid (1.5 ml) was then added and the mixture was stirred at 75° C. After stirring at 75° C. for 6 h, it was allowed to stand overnight, then further sulfuric acid (1.5 ml) was added and the mixture was heated at 75° C. for 8 h. After allowing to stand overnight, it was added to ice water and stirred for 2 h. The commencing crystallization was completed overnight in a refrigerator. The precipitate was then filtered off with suction and dried in a high vacuum. 2.7 g of 3-pentafluorosulfanyl-5-nitrobenzoic acid were obtained. It was possible to obtain a further 530 mg from the mother liquor after extracting three times with methylene chloride, drying the combined methylene chloride phases over magnesium sulfate and concentrating the solvent.
Wird geladen…