Synthesis And Fungicidal Activities Of Quinazolinones And Thienopyrimidines

Quinazolinones have been found to show fungicidal, herbicidal, pestcidal and medicinal activities, and have the applied foreground extensively. In this paper, we studied the synthesis of novel quinazolinones by utilizing aza-Wittig reaction that has the advantage of easily accessible starting material, mild condition and good yields. The spectral properties, biological activities and the condition for cyclization of quinazolinones were also researched and some of them were found to show good fungicidal activities. Sixty five unreported quinazolinones in three series were synthesized. It may be summarized as follows:1. The cyclization of carbodiimide 2 with phenols in presence of solid potassium carbonate was studied further. The results show that it is a good method for preparing of 2-phenoxy(thio)- (3H)-quinzolin-4-ones 4 at room temperature.2. The cyclization of carbodiimide 2 with alcohols in presence of sodium alkoxide was studied firstly. The results show that it is a good method for preparing of 2-alkyloxy-3H-quinzolin-4-ones 15 at normal temperature.3 Attemp to use many ways to synthesize iminophosphorane 8 resulted in a better method B, which has many merits such as short-time, less step, high-yield, and to be easily-saperated. These provide an important way to synthesis thieno[2,3-d] Pyrimidine.4 2-substituted thieno[2,3-d]Pyrimdine 11 were firstly synthesized from aza-Wittig reaction in a very mild condition .5 The biological activities of partial quinzolinones were studied. The results showed that they exhibited fungicidal activities. Especially, 2-alkoxy 3H-quinazolin-4-ones 15 . Most of them exhibited more than 80%(grade B) inhibition of partial fungi in 50mg/L.6 The biological activities of partial thieno[2,3-d]Pyrimidine 11. were studied. The results showed that they exhibited fungicidal activities. Most of them exhibited more than 80% (grade B) inhibition of partial fungi of beet speckl.