Studies on Pyridine Derivatives (Ⅺ):Synthesis and Herbicidal Activities of Both Enantiomers of2-sec-Butylamino-5--1,3,4-thiodiazoles

Both enantiomers of 2-sec-butylamino-5-(2-chloropyrid-4-yl)-1,3,4-thiodiazoles (BCPT),a powerful racemic herbicidal compound which was found in previous research,were synthesized from R- and S-butylamine respectively.The preliminary bioassay results showed that three of the thiodiazoles (racemate and enantiomers) were excellent growth inhibitors to both roots and stems of barnyard grass.The S-(+) enantiomer was the strongest for stem growth inhibition,and R-(-) enantiomer was the weakest.But they had little inhibiting difference on root growth.