Abstract: Compounds of formula (I): wherein X is O or S, R1 is acyl, aldehyde, cycloalkyl, an optionally substituted alkyl, alkenyl or alkynyl, R2 is H. alkyl, hydroxyalkyl, haloalkyl, alkenyl, or alkynyl; substituted alkyl; alkylcarbonyl; R3 and R4 are H, halogen, alkyl, alkenyl, alkynyl, alkoxyl, alkylthio, hydroxyalkyl, haloalkyl, haloalkenyl, or haloalkynyl; or R3 and R4 form an, optionally aromatic or heterocyclic, optionally substituted ring, R5 is H, halogen, trifluoromethyl, —CN, or —NO2; not all of R3, R4, and R5 being H, R6 and R9 are H, halogen, OH; alkyl.