Background: Isatin (IST) is a crucial pharmacologically active compound, chemically known as indole- 1H-2,3-dione. Development of different IST based analogues acquired significant awareness because of its pronounced therapeutic importance such as analgesic, anticancer, anti-inflammatory, antitubercular, antimicrobial, antifungal, antiviral (effective against SARS coronavirus 3C protease) and many other activities, and represents an important class of heterocyclic compounds that can be used as a precursor for the synthesis of many useful drugs.

Objective: Previously, many articles were reported on IST synthesis and its different pharmacological activities but herein, we mentioned 59 different synthesis schemes of several IST derivatives/hybrids derived from the substitution of the nitrogen, aromatic ring, the second and third position of IST along with most potent molecule among each of synthesized libraries with their structural activity relationship (SAR). Using these standardized approaches, several biologically important compounds were developed like sunitinib, nintedanib, indirubin, etc and several studies have been carried out nowadays to develop newer compounds having fewer side effects and also overcome the problem of resistance.

Conclusion: This report critically reviews the different strategies for the designs and synthesis of several IST based compounds having different biological activities with SAR, which can favour further investigation and modification for the development of new and more potent entities.

背景：靛红 (IST) 是一种重要的药理活性化合物，化学上称为吲哚-1H-2,3-二酮。开发不同的基于 IST 的类似物因其在镇痛、抗癌、抗炎、抗结核、抗菌、抗真菌、抗病毒（对 SARS 冠状病毒 3C 蛋白酶有效）和许多其他活性等方面具有显着的治疗重要性而获得了广泛的认识，并代表了一个重要的类别杂环化合物，可用作合成许多有用药物的前体。

目的：以前有很多文章报道了 IST 的合成及其不同的药理活性，但在本文中，我们提到了 59 种不同的合成方案，它们来自于 IST 的氮、芳环、第二和第三位的取代。每个合成文库中最有效的分子及其结构活性关系（SAR）。使用这些标准化方法，开发了几种具有重要生物学意义的化合物，如舒尼替尼、尼达尼布、靛玉红等，目前已经进行了几项研究，以开发具有较少副作用并克服耐药性问题的新型化合物。

结论：本报告批判性地回顾了几种具有不同 SAR 生物活性的基于 IST 的化合物的设计和合成的不同策略，这有助于进一步研究和修改以开发新的和更有效的实体。