[Br:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8](=[N:15]C)([NH:10][C:11](C)(C)C)=[O:9].B(F)(F)F.CCOCC.C1(OC)C=CC=CC=1.FC(F)(F)S(O)(=O)=O.C([O-])(=O)C.[Na+].C(=O)([O-])[O-].[K+].[K+]>FC(F)(F)C(O)=O.ClCCl.O>[Br:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8](=[N:10][CH3:11])([NH2:15])=[O:9]
Cleavage of the tert-butyl group from 2-bromo-N-(1,1-dimethylethyl)-N'-methylbenzenesulfonimidamide by use of trifluoroacetic acid with or without added boron trifluoride etherate was found to be slow at room temperature. 2-Bromo-N-(1,1-dimethylethyl)-N'-methylbenzenesulfonimidamide (0.9 g, 2.9 mmol) recovered from these cleavage experiments and anisole (0.6 g, 5.5 mmol) were dissolved in trifluoroacetic acid (25 mL). Trifluoromethanesulfonic acid (ca. 9 g, 60 mmol) was added and the reaction mixture was stirred at room temperature for 1 hour. Then sodium acetate (5.5 g, 67 mmol) was added and the solvent was evaporated to leave a solid residue. This was dissolved in a mixture of dichloromethane and a small amount of water. Potassium carbonate was added until the mixture became basic. The mixture was partially dried (Na2SO4), filtered through Celite®, redried (Na2SO4), and gravity filtered. Evaporation of the solvent left a slightly brownish oil (1.4 g). This was dissolved in dichloromethane and chromatographed on a column of silica gel using 40:1 CH 2 Cl2 -Et2O followed by 1:1 CH2Cl2 -Et2O as eluant. Fractions containing the product (Rf =0.44, 10:1 CH2Cl2 -Et2O, UV) were evaporated to leave 2-bromo-N'-methylbenzenesulfonimidamide as a colorless oil (0.7 g).
Wird geladen…
