Polo Efrain, Trilleras Jorge, Ramos Juan, Galdámez Antonio, Quiroga Jairo, Gutierrez Margarita
Organic Synthesis Laboratory and Biological Activity (LSO-Act-Bio), Institute of Chemistry of Natural Resources, Universidad de Talca, Casilla 747, Talca 3460000, Chile.
Grupo/Semillero de Investigación en Compuestos Heterocíclicos, Programa de Química, Facultad de Ciencias Básicas, Universidad del Atlántico, Km 7 Antigua vía Puerto Colombia, Barranquilla 081007, Atlántico, Colombia.
Molecules. 2016 Jul 9;21(7):903. doi: 10.3390/molecules21070903.
A small series of tetrahydroindazoles was prepared, starting from 2-acetylcyclohexanone and different hydrazines using reflux and a focused microwave reactor. Microwave irradiation (MW) favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of substituted tetrahydroindazole derivatives. The in vitro antioxidant activity was evaluated using the DPPH and ABTS methods. In these assays, 2-(4-fluorophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f) showed moderate DPPH decoloring activity, while 3-methyl-4,5,6,7-tetrahydro-1H-indazole (3a), 3-methyl-2-phenyl-4,5,6,7-tetrahydro-2H-indazole (3b) and 2-(4-fluorophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f) were the most active in the ABTS assay. All compounds were well characterized by IR, ¹H-, (13)C-NMR and GC-MS spectroscopy and physical data, while the structure of 4-(3-methyl-4,5,6,7-tetrahydro-2H-indazol-2-yl)benzoic acid (3e) was also determined by single crystal X-ray analysis.
以2-乙酰环己酮和不同的肼为原料，采用回流和聚焦微波反应器制备了一小系列四氢吲唑。微波辐射（MW）有利于所需产物的形成，提高了产率并缩短了反应时间。这是一种合成取代四氢吲唑衍生物的简单绿色方法。使用DPPH和ABTS方法评估体外抗氧化活性。在这些试验中，2-(4-氟苯基)-3-甲基-4,5,6,7-四氢-2H-吲唑（3f）表现出中等的DPPH脱色活性，而3-甲基-4,5,6,7-四氢-1H-吲唑（3a）、3-甲基-2-苯基-4,5,6,7-四氢-2H-吲唑（3b）和2-(4-氟苯基)-3-甲基-4,5,6,7-四氢-2H-吲唑（3f）在ABTS试验中活性最高。所有化合物均通过红外光谱、¹H-、(13)C-NMR和GC-MS光谱以及物理数据进行了很好的表征，而4-(3-甲基-4,5,6,7-四氢-2H-吲唑-2-基)苯甲酸（3e）的结构也通过单晶X射线分析确定。
