Structure Modification Of Isation In Indigo Natruralis And Study On In Vitro Antibacterial Activity

Aim It is aimed to modify the structure of isatin that separated from Chinese medicine Indigo naturalis, and evaluate pharmacologic activities of some of target compounds and their derivatives.Methods1.Steam distillation and chromatography were used to separate isatin from Indigo naturalis.2. A novel and convenient organocatalytic tandem reaction has been developed for the asymmetric assembly of saturated aldehydes (or enals), nitroolefins and isatin to produce six-membered oxa-spirooxindole backbones bearing four contiguous stereogenic centers and multiple functional groups with high stereoselectivity.3. Double agar dilution method was used to evaluate in vitro antibacterial activity of some of target compounds.Results1. The Rf value of obtained orange-red crystal is the same as that of the standard isatin by TLC, and the purity was over90%.2.16new isatin derivatives were obtained and characterized by1H NMR,13C NMR and HRMS.3. N-benzyl isatin has a better bacteriostasis than isatin on staphylococcus aureus2-3, saprophytic bacteria5-1and megasphaera elsdenii9-1. Compound7a,7g,7h and compound8with six-membered oxa-spirooxindole backbones don’t have obvious bacteriostasis.Conclusions Isatin derivatives with C-3six-membered oxa-spirooxindole backbones don’t have obvious bacteriostasis, thus the carbonyl group was regarded as a possible antibacterial pharmacophore.