摘要 |
Chemical compounds of the following general formula: <IMAGE> in which: - X is CN, NO2, COCH3, halogen, COOCH3, COOC2H5, SO2CH3, SOCH3, SO2NHCH3, SO2N(CH3)2, CONHCH3, CON(CH3)2, CF3, OCH3, CHO or H; - R1 is H, CH3, C2H5, i-C3H7 or n-C3H7; - R2 is a hydrocarbon group containing 2 to 13 carbon atoms, one or two carbon atoms of which can be substituted by one or two sulphur atoms. |