Abstract:
Recent emergence of microwave-assisted green synthesis as a tool of novel
drug discovery is gaining much interest in the pharmaceutical field. The
dielectric heating procedure found in microwave radiation has improved the
atom- economy and product purity. In terms of green chemistry, reactions
under solvent free condition have gained considerable attention as they
reduce usage of environmentally hazardous solvents. Compounds containing
oxindole pharmacophore such as 3-benzylidene-indolin-2-ones have been
credited to have extensive range of biological applications. The aim of the
current study was to develop novel green synthetic method in the synthesis of
3-benzylidene-indolin-2-ones from oxindole and naturally occurring
aldehydes under microwave radiation. APTES ((3-Aminopropyl)
triethoxysilane) modified silica was used as a solid catalyst to yield the
targeted compounds within 12 minutes. Synthesized compounds (A, B, and
C) were characterized by Nuclear Magnetic Resonance spectroscopy
(1HNMR), Fourier-Transform Infrared spectroscopy (FTIR), and melting
point analysis. Antifungal activity of the compounds was tested against
Candida albicans (ATCC 10231) using well diffusion assay. Compounds A,
B, and C had mean zones of inhibition (ZOI) against Candida albicans as
20.0 mm, 20.0 mm, and 19.3 mm, respectively. Mean ZOI of miconazole
positive control against Candida albicans was 11.3 mm. Both Minimum
Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration
(MFC) of compounds A, B, and C against Candida albicans were 31.2
that 3-benzylidene-indolin-2-ones retains a significant antifungal activity
against Candida albicans. Microwave assisted, solvent free, green synthetic
method was efficiently advanced to synthesize biological active oxindole
derivatives.
