Synthesis Of 1-fluoro-2-arylvinylphosphine Oxides And Tricyclic Heterocycles Containing Pyrazol Moiety

1.A facile and efficient method for the synthesis of(Z)-and(E)-(1-fluoro-2-arylvinyl)phosphine oxides/phosphonates from gem-difluorostyrenes and diphenylphosphine oxide/dialkyl phosphate in the presence of DBU at room temperature was developed.A series of 1-fluorovinyl phosphine oxides/phosphonates were obtained with moderate to excellent yields.In addition,most Z-and E-type isomers of target compounds could be easily separated by column chromatography.2.Herein,an efficient synthesis of pyrazolo[5,1-b]benzothiazole scaffold via Pd-catalyzed intramolecular C–H activation and sequential C-S formation was reported.By starting from easily available 1-phenyl-1H-pyrazole-5-thiol compounds,a series of substituted pyrazolo[5,1-b]benzothiazoles were obtained with moderate to good yields.Interestingly,this reaction didn't need any additional oxidant and the reaction conditions were also suitable to the synthesis of imidazo[2,1-b]benzothiazole derivatives.We also gave a real and successful example of “scaffold hopping” to synthesize YM-201727 analogue for drug research.We also introduced aryl group in 4 position of pyrazolo[5,1-b]benzothiazoles and obtained a series of substituted aryl products of these tricycle compounds in a good yield.Afterwards,we still use 1-phenyl-1H-pyrazole-5-thiol as raw materials to construct new tricyclic 3-methyl-1-phenyl-1H-benzo[4,5]thieno[2,3-c]pyrazoles.