Abstract
Quinoline-2,4-diones reacted with 2-[bis(methylthio)methylene]malononitrile in DMF/Et
3
N to produce 3-(methylthio)-4-oxo-4,5-dihydrofuro[3,2-
c
]quinolone-2-carbonitriles and 3-(methylthio)-4-oxo-4,5-dihydrofuro[3,2-
c
]quinolone-2-carboxamides in state of 2-imino-substituted 4-(methylthio)-5,6-dihydro-2
H
-pyrano[3,2-
c
]quinolone-3-carbonitriles. The structures of all new products were proved using NMR, IR, and mass spectral data. The possible mechanism for the reaction is also discussed.
Graphic abstract