[CH3:1][C:2]1[C:3]([CH3:16])=[CH:4][C:5]2[CH:10]([C:11](O)=[O:12])[S:9][CH2:8][C:7](=[O:14])[C:6]=2[CH:15]=1.C(Cl)(=O)C(Cl)=O.[NH3:23].C(OCC)(=O)C>C1COCC1.CN(C=O)C>[CH3:1][C:2]1[C:3]([CH3:16])=[CH:4][C:5]2[CH:10]([C:11]([NH2:23])=[O:12])[S:9][CH2:8][C:7](=[O:14])[C:6]=2[CH:15]=1In THF (10 ml) was dissolved 6,7-dimethyl3,4-dihydro-1H-2-benzothiopyran-4-one-1-carboxylic acid (0.473 g) followed by addition of oxalyl chloride (0.305 g) and, then, DMF (1 drop). The mixture was stirred at room temperature for 2 hours. This reaction mixture was added to aqueous ammonia (20 ml)--ethyl acetate (40 ml) and the whole mixture was stirred at room temperature for 30 minutes. The ethyl acetate layer was then separated, washed with water, dried (MgSO4) and the solvent was distilled off to give 6,7-dimethyl-3,4-dihydro-1H-2-benzothiopyran-4-one-1-carboxamide (0.38 g, 81%). Recrystallization from ethyl acetate gave colorless plates melting at 197°-198° C.
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