Rhodium-catalysed hydroboration employing new Quinazolinap ligands; an investigation into electronic effects
摘要:
As part of an ongoing effort to improve the efficiency and substrate scope of our Quinazolinap ligand series in the rhodium-catalysed asymmetric hydroboration of vinyl arenes, 2-(p-trifluoromethylphenyl)Quinazolinap and 2-(p-methoxyphenyl)-Quinazolinap have been synthesised and resolved in good yield. These, along with the previously reported 2-(2-pyridyl)-Quinazolinap and 2-(2-pyrazinyl)-Quinazolinap, form part of an electronic series of Quinazolinap ligands synthesised in order to explore electronic effects in this ligand class. The application of this series of ligands to the rhodium-catalysed asymmetric hydroboration of a range of vinylarenes is described. Good conversions and regioselectivities as well as excellent enantioselectivities up to 97% were obtained. 2-(p-Methoxyphenyl)-Quinazolinap demonstrated consistently high enantioselectivities in the hydroboration of sterically demanding vinylarenes. (C) 2010 Elsevier Ltd. All rights reserved.
包含1,2,4-三唑并[4,3- a ]吡啶部分的新型喹唑啉硫醚衍生物的合成,晶体结构和农业抗菌性评价
摘要:
总共设计,合成和评估了22个结合有1,2,4-三唑并[4,3- a ]吡啶部分的喹唑啉硫醚衍生物,并将其作为农业上的抗菌剂进行了评估。在这些化合物中,通过单晶X射线衍射分析进一步证实了化合物6l的化学结构。生物测定结果表明,某些化合物对被测植物病原菌具有显着的体外抗菌活性。例如,化合物6b和6g的抗轴索黄单胞菌pv的EC 50值低至10.0和24.7μg / mL 。红蜘蛛(西飞),分别比市售农用杀菌剂比美噻唑(56.9μg/ mL)好得多。特别地,还发现化合物6b能够抑制病原细菌米氏黄单胞菌(Xanthomonas oryzae pv)。米曲霉(白叶枯病)约12倍于对照叶枯唑更有效,在其EC方面50的值(7.2对89.8微克/毫升)。重要的是,在该系列中,活性最高的化合物6b证明是具有最高亲水性和最低分子量的化合物。体内生物测定进一步显示了6b作为控制Xoo的有前途的植物杀菌剂的应用前景。。另外,还在50μg/