[Br:1][C:2]1[CH:8]=[CH:7][C:5]([NH2:6])=[C:4]([CH2:9][S:10]([C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)(=[O:12])=[O:11])[CH:3]=1.O.[C:20]1(C)C=CC(S(O)(=O)=O)=CC=1.C(OCC)(OCC)OCC.CC([O-])(C)C.[K+].C1COCC1.[NH4+].[Cl-]>O.ClCCCl>[Br:1][C:2]1[CH:3]=[C:4]2[C:5](=[CH:7][CH:8]=1)[NH:6][CH:20]=[C:9]2[S:10]([C:13]1[CH:14]=[CH:15][CH:16]=[CH:17][CH:18]=1)(=[O:11])=[O:12]
A stirred solution of 4-bromo-2-[(phenylsulfonyl)methyl]aniline (3.26 g, 10.00 mmol, p-toluenesulfonic acid monohydrate (0.20 g), triethyl orthoformate (8.32 mL, 50 mmol) and 1,2-dichloroethane (70 mL) is heated at reflux under nitrogen for 5 hours and then at room temperature for 16 hours. The reddish reaction is concentrated in vacuo to a red oil. The resulting crude intermediate iminoether is stirred in dry THF (50 mL) and treated with 1.0M KOtBu in THF (13 mL, 13 mmol). After 5 min, a tan precipitate is evident. After 1 hour, the reaction is treated with water (30 mL) and NH4Cl (0.60 g), extracted with CH2Cl2 (150 mL), dried (MgSO4), filtered and concentrated in vacuo to a light orange solid. Trituration with ethyl acetate and hexanes affords the title compound as a light orange solid (2.78 g, 72%). Mp: 176-178° C. MS (ES−): 334 (M−H).
Wird geladen…
