Synthesis of high-activited weedicide quinclorac and QSAR analysis

A new high activated organic weedicide quinclorac (3,7-dicholoro-8-quinoxylic acid) was presented, and the optimal synthesis condition of the key step-Skraup cyclization was developed. A new synthesis process by using the catalyst of KI was set up, and the yield increased to 95.5%. The relationship between structure and activity of quinclorac and its derivatives was studied to find more active and more mild weedicide,12 derivatives of this acid were synthesized, and the biological activities of all these compounds were detected,the QSAR equation of this series of compounds was established by Hansch method, which shows that the biological activity is linearly correlated with parameters L, MR, B1 , B2 and B4, and -CH2-CH = CH2 substituted quinclorac ester was more active and more mild weedicide analysised from QSAR equation.