Multi Route Synthesis Of Substituted Indole Oxide

Oxyindole ketone and its derivatives are important alkaloid skeleton compounds,which widely exist in nature and have strong physiological and pharmacological activities.Recently,one of the most interesting filed of organic synthesis is how to construct the multifunctional oxyindole rapidly and efficiently.Therefore,It is valuable to study the structure of oxindolones.In this work,we study to use several ways to replace Oxyindole ketone.The results consist of two parts:the first part is the hydrogenation of 3-alkyleneoxindole;the second part is the Michael Michael double addition of 3-alkyleneoxindole with trimethylcyanosilane.The first part,the selective hydrogenation of 3-alkyleneoxyindole and acetone alcohol was carried out with potassium carbonate as additive and KI as catalyst.The reaction was carried out at room temperature in 2h and a series of 3-substituted indoles were obtained in good yields.The products 2a-l were characterized by ¹H NMR,¹³C NMR,IR and HRMS.The structure of product 2e was confirmed by X-ray single crystal diffraction.The Crude product of GC-MS showed that acetone ester was formed in addition to reduction product.Therefore,we proposed a possible reaction mechanism,in which acetone alcohol was used as reducing agent.The othet part,a series of novel indole oxide derivatives with dicyano functional groups were synthesized by Michael-Michael double addition reaction of 3-alkyleneoxyindole and trimethylcyanosilane with potassium carbonate as catalyst and water as additive.The reaction was carried out in 1,4-dioxane as solvent,refluxing for1h,with good yield.The products 3a-j were all new compounds,purified by recrystallization of ethyl acetate,and characterized by ¹H NMR,¹³C NMR,IR and HRMS.