| 摘要 |
Prodn. of thioureas of formula (I) (R1 and R2 are H, halo or lower alkyl; and R3 and R4 are 1-5C alkyl, 3-4C alkenyl or benzyl) comprises first reacting an R1, R2-amiline. (II) with CS2 and a base in presence of a water-contg. solvent. The resulting phenyldithiocarbamic acid salt is then reacted with R3R4NH. The pref. solvent is a water: alcohol mixt. of pref. ratio 8:2:7:3, esp. with methanol. Bases are esp. Na2Co3 or K2Co3 and the mole ratio (II):CS2:base is esp. 1:1.1:1.1. In the second stage, 1-2.3, esp. 1.5-2.1 moles amine are used per mole (II).(I) are known insecticides, acaricides, ectoparasiticides and herbicides. This simple method gives 90% yields on (II) (even higher if unreacted (II) is recovered). Relatively small amts. of impurities have to be removed from waste streams and the CS2 reacts quickly and quantitatively so is not a significant explosion risk.
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