It has already been reported that 3-(indol-2-yl)quinoxalin-2-ones have a potent inhibitory effect on the growth of tumor cells based on anti-angiogenesis activity. We have also carried out a structure-activity relationship (SAR) study of 3-(indol-2-yl)quinoxalin-2-ones, which showed a potent inhibitory activity toward the vascular endothelial growth factor (VEGF)-induced proliferation of human mesangial cells and the VEGF-induced auto-phosphorylation of human umbilical vein endothelial cells. Moreover, one of these compounds has a potent medicinal effect based on anti-angiogenic action, by oral administration (Chart 1, 9). However, since the existing synthetic methods for the preparation of 3-(indol-2-yl)quinoxalin-2-ones consist of multiple steps some of which require strict anhydrous conditions, a convenient and simple synthetic method in place of the existing method is desirable. As a result of the investigations into the synthetic procedures, 3-(3-substituted indol-2-yl)quinoxalin-2-ones can be easily prepared by the condensation of 3-substituted indoles with quinoxalin-2-ones in the presence of trifluoroacetic acid (TFA). Herein, we report the examination of these reaction conditions and the application of this new synthetic method to the synthesis of the derivatives as VEGF inhibitors.

中文翻译：

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方便合成3-（3-取代的吲哚-2-基）喹喔啉-2-酮作为VEGF抑制剂的方法。

已经报道了3-（吲哚-2-基）喹喔啉-2-酮基于抗血管生成活性对肿瘤细胞的生长具有有效的抑制作用。我们还进行了3-（吲哚-2-基）喹喔啉-2-酮的结构-活性关系（SAR）研究，该研究显示了对血管内皮生长因子（VEGF）诱导的人增殖的有效抑制作用系膜细胞和VEGF诱导的人脐静脉内皮细胞自身磷酸化。而且，这些化合物之一通过口服给药具有基于抗血管生成作用的有效药物作用（图1、9）。但是，由于现有的制备3-（吲哚-2-基）喹喔啉-2-酮的合成方法包括多个步骤，其中一些需要严格的无水条件，需要一种方便和简单的合成方法来代替现有方法。作为对合成方法的研究的结果，可以通过在甲苯磺酸存在下将3-取代的吲哚与喹喔啉-2-酮缩合来容易地制备3-（3-取代的吲哚-2-基）喹喔啉-2-酮。三氟乙酸（TFA）。在本文中，我们报告了对这些反应条件的检查以及这种新的合成方法在合成作为VEGF抑制剂的衍生物中的应用。