New Efficient Synthesis of 5,6-Disubstituted-3-phenyl-1,2,3-triazolo[4,5-d]pyrimidin-7-ones via a Tandem Aza-Wittig Reaction

Twelve novel 5,6-disubstituted-3-phenyl-1,2,3-triazolo[4,5-d]pyrimidine-7-ones 5a–5l were designed and successfully synthesized via tandem aza-Wittig and annulation reactions of the corresponding iminophosphorances 2, aromatic isocyanate, and substituted thiophenols in satisfactory yields. The results from the preliminary bioassay indicated that some of these compounds possess inhibitory activities against the root and stalk of Brassica napus(rape) as well as Echinochloa crusgalli (barnyard grass) at the dosages of 100 mg/L and 10 mg/L, respectively.