[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C@H:8]([N:12]1[CH2:17][CH2:16][C:15]2[S:18][CH:19]=[CH:20][C:14]=2[CH2:13]1)[C:9](N)=[O:10].OS(O)(=O)=O.[C:26](=O)([O-])[O-:27].[Na+].[Na+]>CO>[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C@H:8]([N:12]1[CH2:17][CH2:16][C:15]2[S:18][CH:19]=[CH:20][C:14]=2[CH2:13]1)[C:9]([O:27][CH3:26])=[O:10]5 g of (S)-(+)-(2-chlorophenyl)-(6,7-dihydro-4H-thieno[3,2-c]pyrid-5-yl)acetamide was dissolved in 50 ml methanol and the solution was cooled till −15° C. 15 mL (0.28 mol) of conc. H2SO4 (98%) was added dropwise in 1 hr maintaining the temperature till −15° C. After the completion of addition the reaction mixture was gradually increased, and stirred at 31° C. for 30 min, and then refluxed at 70° C. for 21 hrs. The solvent was distilled off under reduced pressure and to the residue 50 mL of water was added and stirred for 30 min followed by cooling to −5° C. The pH of reaction mixture was adjusted between 9 to 10 using aq. sodium carbonate. The residue was extracted with 100 mL ethyl acetate. The organic layer was dried over anhydrous Na2SO4, and evaporated under vacuum. The yield was 3.8 g of crude product purified by column, using hexane:ethyl acetate (9:1) as eluent.
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