Eight new 5,7-disubstituted-2-(5-aryl-2-furoylimino)-[1,2,4]-thiadiazolo[2,3-a]pyrimidine derivatives were synthesized under ultrasonic irradiation. All of them are new compoundsand their structures were exactly confirmed by IR, ¹H NMR spectra and elemental analysis. Our method using the ultrasonic irradiation under the conditionof phase transfer catalyst (PTC) has the advantages of short reaction time andgood yield. The preliminary biological tests show that some of the target compounds have some inhibitory activities against weeds.

Key words: acyl thiourea, [1,2,4]-thiadiazolo[2,3-a]pyrimidine, ultrasonic irradiation, phase transfer catalysis, synthesis, bioactivity