Triethylamine → 6-chloro-2,3-dihydro-3-dimethylaminomethylene-4H-1-benzothiopyran-4-one
Reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[S:10][CH2:9][CH2:8][C:7](=[O:11])[C:6]=2[CH:12]=1.CO[CH:15](OC)[N:16]([CH3:18])[CH3:17].C(N(CC)CC)C>C1C=CC=CC=1>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[S:10][CH2:9][C:8](=[CH:15][N:16]([CH3:18])[CH3:17])[C:7](=[O:11])[C:6]=2[CH:12]=1Participants
5
Procedure
A solution of 6-chloro-2,3-dihydro-4H-1-benzothiopyran-4-one (30 g), N,N-dimethylformamide dimethyl acetal (80 ml), and triethylamine (31.4 ml) in benzene (400 ml) was refluxed with stirring for 1 hour and then about three-fourths of the solvent were distilled slowly at atmospheric pressure over a period of approximately 1 hour. Benzene (300 ml) was added to the reaction mixture and the solvent was distilled again. To the residue was added diethyl ether (150 ml) and the mixture was triturated to give 6-chloro-2,3-dihydro-3-dimethylaminomethylene-4H-1-benzothiopyran-4-one (34 g).