Trifluoroacetic acid → N-[4-(2-bromoethyl)phenyl]methanesulfonamide
Reaction equation
[Br:1][CH2:2][C:3]([C:5]1[CH:15]=[CH:14][C:8]([NH:9][S:10]([CH3:13])(=[O:12])=[O:11])=[CH:7][CH:6]=1)=O.FC(F)(F)C(O)=O.C([SiH](CC)CC)C>>[Br:1][CH2:2][CH2:3][C:5]1[CH:6]=[CH:7][C:8]([NH:9][S:10]([CH3:13])(=[O:12])=[O:11])=[CH:14][CH:15]=1Participants
4
Procedure
According to the method of Doyle and coworkers in C. T. West, et al., J. Org. Chem. 38, 2675 (1973), a stirred mixture of 4'-(2-bromoacetyl)methanesulfonanilide as prepared in Preparation 4 (6.0 g, 0.021 mol), trifluoroacetic acid (32.7 g, 0.287 mol) and triethylsilane (10.5 g, 0.0902 mol), under N2, is refluxed for 2.5 days and concentrated in vacuo. The residue is mixed with toluene, concentrated, dissolved in 1N NaOH and washed with Et2O. The aqueous layer is acidified with HCl to pH 2 and extracted well with Et2O. The combined organic extracts are dried (MgSO4) and concentrated in vacuo. The residue is chromatographed on silica gel (300 g) with 1.5% MeOH:CH2Cl2 and N-[4-(2-bromoethyl)phenyl]methanesulfonamide is crystallized from EtOAc:SSB, mp: 92°-94° C.