Thiophene → 3-oxo-2-(2-thienyl)-3,4-dihydro-2H-1,4-benzothiazine
Reaction equation
Cl[CH:2]1[C:7](=[O:8])[NH:6][C:5]2[CH:9]=[CH:10][CH:11]=[CH:12][C:4]=2[S:3]1.[S:13]1[CH:17]=[CH:16][CH:15]=[CH:14]1>C(Cl)Cl>[O:8]=[C:7]1[NH:6][C:5]2[CH:9]=[CH:10][CH:11]=[CH:12][C:4]=2[S:3][CH:2]1[C:14]1[S:13][CH:17]=[CH:16][CH:15]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 2-chloro-3-oxo-3,4-dihydro-2H-1,4-benzothiazine (9.38 g) and thiophene (7.91 g) in methylene chloride (250 ml) is added in portions stannic chloride (12. 2 g) at 0° to 5° C. After stirring at the same temperature for 45 minutes, the mixture is poured into ice water, and the organic layer is separated. The aqueous layer is extracted with ethyl acetate, and the ethyl acetate layer is combined with the above organic layer and distilled to remove the solvent. The resulting solid material is recrystallized from ethanol to give 3-oxo-2-(2-thienyl)-3,4-dihydro-2H-1,4-benzothiazine (8.17 g) as crystals.