Chlorosulfonic acid → (7-Chlorosulfonyl-6-methoxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester
Reaction equation
[CH2:1]([O:3][C:4](=[O:17])[CH2:5][C:6]1[C:7]2[CH:14]=[CH:13][C:12]([O:15][CH3:16])=[CH:11][C:8]=2[S:9][CH:10]=1)[CH3:2].[Cl:18][S:19](O)(=[O:21])=[O:20]>C(Cl)Cl>[CH2:1]([O:3][C:4](=[O:17])[CH2:5][C:6]1[C:7]2[CH:14]=[CH:13][C:12]([O:15][CH3:16])=[C:11]([S:19]([Cl:18])(=[O:21])=[O:20])[C:8]=2[S:9][CH:10]=1)[CH3:2]Participants
4
Procedure
To a solution of compound from step 2 (1.0 g, 4.0 mmol) in CH2Cl2 (10 mL) was added chlorosulfonic acid (0.56 mL, 8.0 mmol). The resulting mixture was stirred for 4 hours at room temperature. The solvent was evaporated in vacuo and the residue was dissolved in EtOAc. The solution was washed with Na2CO3, brine and dried over Na2SO4. Evaporation of solvent afforded 50 mg of desired compound. 1H NMR (400 MHz, CDCl3) δ 8.08 (d, 1H), 7.38 (s, 1H), 6.90 (d, 1H), 4.21 (q, 2H), 4.02 (s, 2H), 4.01 (s, 3H), 1.24 (t, 3H).