Alzheimer’s disease is an irreversible, progressive brain disorder that slowly destroys memory and cognition skills. Dysfunction of acetylcholine containing neurons in the brain contributes substantially to the cognitive decline observed in Alzheimer's disease. Hence, our focus is to synthesize cholinesterase inhibitors. A series (22 compounds) of 6- and 9-substituted derivatives of 2,3,4,9-tetrahydro-1H-carbazole have been prepared and in vitro evaluated for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by Ellman’s method. By comparing selectivity with standard drug donepezil, amino derivative 3, methylamino derivative 4 and butyl nitro derivative 17 have been found to be selective AChE inhibitors. Borsche-Drechsel cyclization reaction has been carried out to synthesize 2,3,4,9-tetrahydrocarbazole ring followed by nitration, reduction and derivative synthesis.

中文翻译：

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2,3,4,9-四氢-1H-咔唑衍生物作为选择性乙酰胆碱酯酶抑制剂的合成和评价：潜在的抗阿尔茨海默氏病药物

阿尔茨海默氏病是一种不可逆的进行性脑部疾病，会逐渐破坏记忆和认知能力。大脑中含有乙酰胆碱的神经元的功能障碍是阿尔茨海默氏病中认知功能下降的重要原因。因此，我们的重点是合成胆碱酯酶抑制剂。已经制备了2,3,4,9-四氢-1 H-咔唑的6个和9个取代衍生物的一系列化合物（22个化合物），并通过Ellman方法体外评估了其对乙酰胆碱酯酶（AChE）和丁酰胆碱酯酶（BChE）的抑制作用。通过与标准药物多奈哌齐，氨基衍生物3，甲基氨基衍生物4和丁基硝基衍生物17的选择性进行比较已经发现是选择性的AChE抑制剂。已经进行了Borsche-Drechsel环化反应以合成2,3,4,9-四氢咔唑环，然后硝化，还原和衍生物合成。