| abstract |
A method for preparing derivatives of formula (I), wherein R is an alkyl, alkoxy, alkylthio, polyfluoroalkyl, polyfluoroalkoxy, alkenyl, phenyl, alkylsulphonyl, alkoxycarbonyl, amino, cyano, sulphonamide or dialkylcarbamyl radical, characterized in that a derivative of formula (II), wherein R has the same meaning as in formula (I), is reacted with nitronium tetrafluoroborate and derivatives of formula (II). |