Department of Chemistry, Shri Chhatrapati Shivaji Mahavidyalaya, 413701, Shrigonda, Ahmednagar (M. S.), India.
Department of Chemistry, Dada Patil Mahavidyalaya, 414402, Karjat, Ahmednagar (M.S.), India.
Chem Biodivers. 2023 Mar;20(3):e202201017. doi: 10.1002/cbdv.202201017. Epub 2023 Feb 27.
Fischer indole synthesis of indole by using phenyl-hydrazine and acetaldehyde resulted 1H-Indole while phenyl-hydrazine reacted with malonaldehyde gives 1H-Indole-3-carbaldehyde. Also Vilsmeier-Haack formylation of 1H-Indole gives 1H-Indole-3-carbaldehyde. 1H-Indole-3-carbaldehyde were oxidized to form 1H-Indole-3-carboxylic acid. 1H-Indole reacted with excess of BuLi at -78 °C using dry ice also gives 1H-Indole-3-carboxylic acid. Obtained 1H-Indole-3-carboxylic acid was converted to ester and ester in to acid hydrazide. Finally 1H-Indole-3-carboxylic acid hydrazide reacted with substituted carboxylic acid gives microbial active indole substituted oxadiazoles. Synthesized compounds 9a-j showing promising in vitro anti microbial activities against S. aureus bacteria compared with Streptomycin. Compound 9a, 9f and 9g showing activities against E. coli compared with standards. Compound 9a and 9f are found potent active against B. subtilis compared with reference standard while compound 9a, 9c and 9j active against S. typhi.
费歇尔吲哚合成法用苯肼和乙醛合成吲哚得到 1H-吲哚，而苯肼与丙二醛反应得到 1H-吲哚-3-甲醛。此外，Vilsmeier-Haack 甲酰化反应也可以得到 1H-吲哚-3-甲醛。1H-吲哚-3-甲醛被氧化形成 1H-吲哚-3-羧酸。1H-吲哚在-78°C 下用干冰与过量的 BuLi 反应也得到 1H-吲哚-3-羧酸。得到的 1H-吲哚-3-羧酸被转化为酯，酯再转化为酸酰肼。最后，1H-吲哚-3-羧酸酰肼与取代的羧酸反应得到具有微生物活性的吲哚取代的噁二唑。与链霉素相比，合成的化合物 9a-j 对金黄色葡萄球菌具有良好的体外抗微生物活性。与标准品相比，化合物 9a、9f 和 9g 对大肠杆菌具有活性。与参比标准品相比，化合物 9a 和 9f 对枯草芽孢杆菌具有更强的活性，而化合物 9a、9c 和 9j 对伤寒沙门氏菌具有活性。
