Investigation of the Biological Activity of Pyrrolo[1,2-a]imidazole Derivatives Produced by a Green One-Pot Multicomponent Synthesis of Ninhydrins
Authors: Barani Khatereh Khandan , Khandan Samira , Shirangi Hannaneh Sadat , tabarsaei Navisa 
Published: June 2024

Aims & Objective:

This study entailed the creation of a new variation of pyrroloimidazoles
with exceptional efficacy through chemical synthesis. The synthesis was accomplished by
tricomponent reactions utilizing ninhydrins, diamines, and activated acetylenic compounds in an
aqueous setting, leading to significant yields. The antioxidant properties of recently synthesized
Pyrroloimidazoles derivatives have been ascribed to the existence of NH and OH groups, which
were evaluated using two techniques. The antimicrobial effectiveness of recently developed pyrroloimidazoles
was evaluated using a disk diffusion technique against both Gram-negative and
Gram-positive bacteria.

Materials and Methods:

The study team utilized high-quality starting chemicals, solvents, and
reagents with consistent chemical and physical properties. The Shimadzu IR-460 spectrometer
was used in a KBr medium to get the Ft-IR spectra of the synthesized nanocatalyst. Furthermore,
we employed a Bruker DRX-400 AVANCE spectrometer to acquire 1H-NMR and 13C-NMR
spectra of the synthesized compounds. The spectrometer utilized in this investigation functions
at a frequency of 400 MHz. The solvent employed for the spectra of produced compounds was
CDCl3, with TMS serving as the internal standard. The mass spectra of the produced compounds,
which have an ionization potential of 70 eV, were obtained using the Finnigan MAT
8430 spectrometer. Elements of produced compounds were subjected to elemental analysis
using the Heraeus CHN-O-Rapid analyzer.

Results:

This work investigated the three-component reaction involving ninhydrins 1, diamines
2, and electron-deficient acetylenic compounds 3 for the eco-friendly production of pyrroloimidazoles
derivatives 4 in water-based solutions at normal temperature. The results indicated that
these molecules displayed noteworthy efficacy, similar to that of conventional antioxidants. Also,
the results indicated that the synthesized pyrroloimidazoles have bacteriostatic properties.

Conclusion:

In summary, this study aimed to examine the environmentally friendly characteristics
of ninhydrins, diamines, and electron-deficient acetylenic compounds when dissolved in water
at normal room temperature. The research resulted in the successful production of new pyrroloimidazole
derivatives with a high rate of success. This study conducted a more in-depth
analysis of the antioxidant properties of the synthesized pyrroloimidazoles 4a-4d by the utilization
of two techniques: DPPH radical scavenging and FRAP assays. The results indicated that
these molecules displayed noteworthy efficacy, similar to that of conventional antioxidants.
Furthermore, we utilized both Gram-positive and Gram-negative bacteria to showcase the antibacterial
effectiveness of the synthesized pyrroloimidazoles by the disk diffusion technique.
The results indicated that the synthesized pyrroloimidazoles have bacteriostatic properties. These
reactions provide benefits, such as efficient utilization of atoms, generation of large quantities
of products, and straightforwardness of the reaction.