Synthesis and biological evaluation of spirofused pyrazole and pyrrolidine hybrids from tryptanthrin

Twenty-two spirofused heterocycles containing tryptanthrin - pyrazole/pyrrolidine hybrids were synthesized via classical (3 + 2) cycloaddition reaction of ethyl ( E )-2-(12-oxoindolo[2,1- b ]quinazolin-6(12 H )-ylidene)acetate with nitrile imine / azomethine ylide. The compounds were screened in vitro for antibacterial activity against the ESKAPE pathogen panel, from which spiropyrazoles 3d and 3f (MIC = 8 µg m/L) were found to be most potent against S. aureus ATCC 29213. Anticancer evaluation of the molecules against HCT-116 human colon cancer cell line by MTT assay indicated dispiropyrrolidines 6a and 6c exhibited highest activity with LC₅₀ values of 23.57 µg/mL and 32.99 µg/mL respectively. Molecular docking studies demonstrated the potential of 6a and 6c as promising candidates for modulating the activity of the IDO1 protein. These findings further support the experimental results obtained from in vitro biological studies and highlight the prospective utility of pyrazole/pyrrolidine derivatives for future therapeutic applications.