Synthesis and bioactivity of novel triazolo [1,5-a] pyrimidine derivatives[3]

In an attempt to discover novel compounds with high herbicidal activity and lout, toxicity, a series of novel 1,2,4-triazolo[1,5-a]pyrimidine derivati ves, a-(5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine-2-thio)acetamides 3 an d alpha-(5,7-dimethyl-1,2, 4-triazolo[1,5-a]pyrimidine-2-sul-fonyl)acetamid es 4, have been designed and synthesized by a three-step synthetic route. T he structures of all compounds prepared were confirmed by elemental analyse s and by H-1 NMR and mass spectroscopy. The results of preliminary, bioassa y indicate that the title compounds possess good herbicidal activity agains t rape (Brassica campestris L.) and barnyardgrass (Echinochloca crusgalli L .) (C) 2001 John Wiley & Sons, Inc.