Asymmetric Synthesis of Trifluoromethyl Substituted Spiro [Indoline-3,4′-Pyrano[2,3-c]Pyrazole] Derivatives with Chiral Bifunctional Organocatalysts

2023-9-11
Özcan, Bilge Deniz
Spirocyclic compounds have always attracted interest since they appear as a structural core in a wide range of natural products and bioactive molecules. The spirooxindole skeleton is the core structure of several pharmaceuticals with anticancer, antimalarial and enzyme inhibitor properties. In this study, the main objective is to obtain highly enantiomerically enriched spiro[indoline-3,4’-pyrano[2,3-c]pyrazole] derivatives by evaluating Tanyeli Research Group’s novel bifunctional organocatalysts. Spiro[indoline-3,4’-pyrano[2,3-c]pyrazole] products were synthesized via Michael addition of trifluoromethyl substituted pyrazolone to isatylidene ethyl cyanoacetate and isatylidene malononitrile derivatives. In the first part, optimization studies were performed by changing catalyst loading, solvent, temperature, substrate ratio and concentration. In the second part of the studies, isatylidene ethyl cyanoacetate and isatylidene malononitrile derivatives were synthesized in order to conduct derivatization studies. 12 novel spiro[indoline-3,4’-pyrano[2,3-c]pyrazole] derivatives were synthesized with excellent enantioselectivities up to 99% in relatively short reaction duration and good yields up to 97% by using 2 mol% organocatalyst at room temperature.
Citation Formats
B. D. Özcan, “Asymmetric Synthesis of Trifluoromethyl Substituted Spiro [Indoline-3,4′-Pyrano[2,3-c]Pyrazole] Derivatives with Chiral Bifunctional Organocatalysts,” M.S. - Master of Science, Middle East Technical University, 2023.