Studies On Synthesis And Herbicidal Activity Of Thieno[2,3-d] Pyrimidine Derivatives

Thienopyrimidine derivatives occupy a special position among heterocycliccompounds because they are structural analogues of biogenic purines and can beconsidered as potential nucleic acid antimetabolites, which have been focus of greatinterest because of their large range of pharmacological activities as antifungal,antibacterial, insecticidal, hypnotic, antiallergic, antiviral, antitumor, and herbicidalactivity. They have become a research hotspot in pesticide and medicine, and havebroad application prospects and theoretical significance.In this paper,2-amino-3-ethoxycarbonyl-5-ethylthiophene, obtained fromreaction of butyraldehyde, ethyl cyanoacetate, sulfur and triethylamine, reacted withtriphenylphosphine, hexachloroethane and triethylamine to give iminophosphorane ingood yield while up to84%. Further aza-Wittig reactions of iminophosphorane witharomatic isocyanates gave the carbodiimides, which were reacted with aromaticthiophenol or hydrazide to give thieno[2,3-d]pyrimidin-4(3H)-one derivatives in thepresence of catalytic amounts of K2CO3or EtONa in good yield. The raw material ofaza-wittig reaction is easy to get, with milder conditions and the yield of products ishigher. The synthesis of compounds have not been reported in the literature, spectralproperties and herbicidal activity of their have been systematically studied. Thespecific contents are as follows:1.Two series, a total of43new compounds were synthesized through theexperiment. The concrete types are as follows:Ⅰ:2-arylamino-3-aromaticamidethieno[2,3-d]pyrimidin-4(3H)–onederivatives(24)Ⅱ:2-arylthio-3-aryl thieno [2,3-d] pyrimidin-4(3H)–one derivatives(19)2.To preliminary tests of the herbicidal activity of new compounds, throughexperiments, we found that some compounds exhibited excellent biological activity ofweeding, and analyzes the relationship between the structure and herbicidal biologicalactivity of the target compounds, in order to provide a reference to the furtherresearch of new pesticides.