[S:1]1[CH:5]=[CH:4][C:3]([C:6]2[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=2[CH2:12]Br)=[CH:2]1.N1C=CC=CC=1.CN(C)C1C=CC(N=[O:29])=CC=1.[OH-].[Na+].Cl>C(Cl)(Cl)Cl.C(O)C.O>[S:1]1[CH:5]=[CH:4][C:3]([C:6]2[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=2[CH:12]=[O:29])=[CH:2]1To a solution of Compound 2b (1.98 mmol) in chloroform (5 mL) was added pyridine (9.88 mmol) and the reaction mixture heated at reflux for 1 hour under nitrogen. The solvent was removed in vacuo and the residue triturated with diethyl ether to give a white solid. The solid was dissolved in 95% aqueous ethanol (10 mL ) and N,N-dimethyl-4-nitrosoaniline (1.98 mmol) was added with stirring followed by the addition of sodium hydroxide (4.0 mmol) in water (3 mL). The reaction mixture was stirred for 16 hours at ambient temperature and then 6N hydrochloric acid (3 mL) was added. After 30 minutes, the solvent was removed in vacuo and the residue was diluted with water (10 mL) and extracted with diethyl ether (2×30 mL). The combined organic phases were washed with saturated aqueous sodium bicarbonate, brine and the solvent removed in vacuo to give crude Compound 2c as an oil.
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