Relationship Between the structure of Newly Synthesized derivatives of 1,3,4-oxadiazole Containing 2-Methylphenol and their Antioxidant and Antibacterial Activities
作者:Shaimaa Abed Saoud、Khalid Fahad Ali、Raied Mustafa Shakir
DOI:10.13005/ojc/330423
日期:2017.8.28
1,3,4-oxadiazole-5-thion ring (2) successfully formed at position six of 2-methylphenol and five of their thioalkyl (3a-e). Furthermore 6-(5-(Aryl)-1,3,4-oxadiazol-2-yl)-2-methylphenol (5a-i) were formed at position six by two method. The first method was from cyclization their corresponding hydrazones (4a-e) of 2-hydroxy-3-methylbenzohydrazide (1) using bromine in glacial acetic acid. The second method was from cyclization the hydrazide with aryl carboxylic acid in the presence of phosphorusoxy chloride. The newly synthesized compounds were characterized from their IR, NMR and mass spectra. The antioxidant properties of these compounds were screened by 2,2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) assays. Compound (4d) and (5h) exhibited significant antioxidant properties in both assays, compared to ascorbic acid, while compound (4e) exhibited slightly less antioxidant properties than ascorbic acid. Antibacterial activity was tested for the twenty one compounds against eight microorganisms (gram negative and gram positive). Compound (4d) and (5d) exhibited significant antibacterial activities compared to Amoxicillin and Kanamycin as antibiotic standards.
1,3,4-噁二唑-5-硫环(2)成功地在2-甲基苯酚的第六位和五种其硫烷基衍生物(3a-e)中形成。此外,通过两种方法在第六位合成了6-(5-(芳基)-1,3,4-噁二唑-2-基)-2-甲基苯酚(5a-i)。第一种方法是使用冰醋酸中的溴化物对2-羟基-3-甲基苯肼(1)的相应肼化合物(4a-e)进行环化。第二种方法是将肼与芳香酸在磷氧化氯的存在下进行环化。新合成的化合物通过其红外光谱(IR)、核磁共振(NMR)和质谱(MS)进行表征。这些化合物的抗氧化性能通过2,2-二苯基-1-皮克里尔肼(DPPH)和铁还原抗氧化能力(FRAP)测定进行筛选。与抗坏血酸相比,化合物(4d)和(5h)在这两种测定中表现出显著的抗氧化特性,而化合物(4e)的抗氧化特性则略低于抗坏血酸。对21种化合物针对8种微生物(阴性革兰氏菌和阳性革兰氏菌)进行了抗菌活性测试。与抗生素标准阿莫西林和庆大霉素相比,化合物(4d)和(5d)表现出显著的抗菌活性。