A new and efficient one-pot synthesis of indoles

Investigation of Potential Effects of Some Indole Compounds on the Glutathione S-Transferase Enzyme

Glutathione S-transferases (GSTs) belong to the superfamily of multifunctional detoxification isoenzymes with an important role in cellular signaling. They can prevent reactive electrophilic compounds from harming the body by covalently binding identical type of moleculs to each other. GSTs can be used alone or in combination for cancer detection or diagnosis, in addition to therapeutic interventions. In recent years, indoles have become important due to their structural properties and biological activities such as antitubercular, antiulcer, anti-oxidant, and antidiabetic, as well as for the development of new anticancer agents. The current research investigated effects of some indoles with 3-carboxaldehyde structure on the GST enzyme activity. Impacts of various concentrations of indoles on the in vitro GST activity were examined. While IC50 values for the compounds ranged from 0.042 to 1.570 mM, Ki values changed between 0.018 ± 0.01 and 1.110 ± 0.15 mM. 6-Methylindole-3-carboxaldehyde (1b) exhibited the highest inhibitory effect among the indoles examined. Indole derivatives used in the study can be evaluated in further pharmacological studies due to their effects on GST activity.

Crystallographic, spectral and computational studies on (S)-4-(4-aminobenzyl) oxazolidin-2-one

The experimental geometry (XRD), vibrational (IR and Raman), electronic (UV-visible) and NMR spectra of (S)-4-(4-Amino-benzyl)-oxazolidin-2-one (ABO) have been corroborated with the corresponding first principle calculated values at DFT using hybrid B3LYP exchange correlation functional invoking 6-311++g(d, p) basis set. The optimized geometrical parameters were found to be in satisfactory agreement with the experimental values obtained from the X-ray diffraction structural features of ABO. The scaled down computed vibrational frequencies with appropriate scaling factors were in good correspondence with the experimental observations. Room-temperature ¹H and ¹³C nuclear magnetic resonance (NMR) studies were supported by advanced density functional theory calculations. The theoretical spectrograms of FT-IR, FT-Raman, ¹H NMR, ¹³C NMR and UV of the title compound have been constructed and compared with experimental spectra and Hirshfeld surface analysis has also been made to study the intermolecular interactions. The electronic structure of the title compound has also been studied in terms of HOMO, LUMO and MESP diagrams.

Applications of Bartoli indole synthesis

In 1989, the reaction of vinyl magnesium halides with ortho-substituted nitroarenes leading to indoles was discovered. This reaction is now frequently reported as the "Bartoli reaction" or the "Bartoli indole synthesis" (BIS). It has rapidly become the shortest and most flexible route to 7-substituted indoles, because the classical indole syntheses generally fail in their preparation. The flexibility of the Bartoli reaction is great as it can be extended to heteroaromatic nitro derivatives and can be run on solid support. This review will focus on the use of the Bartoli indole synthesis as the key step in preparations of complex indoles, which appeared in the literature in the last few years.

Marine Sponge/H3PO4: As a Naturally Occurring Chiral Catalyst for Solvent-free Fischer-Indole Synthesis

Background

A new and efficient method have been developed for the synthesis of different indole derivatives from various ketones, having at least one hydrogen atom attached to each of their α-carbon atoms, and hydrazines in solvent-free conditions, using marine sponge/H₃PO₄ as a naturally occurring chiral catalyst.

Objectives

This study recommended the use of marine sponge/H₃PO₄ as a naturally occurring chiral catalyst for preparation of phenylhydrazones from ketones having one α-hydrogen and subsequent cyclisation of the products to indoles.

Materials and Methods

The reaction was carried out by mixing the phenylhydrazine, ketone, and marine sponge/H₃PO₄ powder in mortar and pestle; the mixture was ground at room temperature in an appropriate time until TLC show the completion of the reaction. The product extracted by CH₂Cl₂ and evaporation of solvent yields the products.

Results

In this research work, several indoles are synthesized using phenylhydrazine and aliphatic or aromatic ketone as starting materials, in the presence of marine sponge/H₃PO₄ powder as a natural catalyst under solvent-free condition.

Conclusions

We found marine sponge/H₃PO₄ to be an effective catalyst for indolisation of phenylhydrazones from ketones having α-hydrogens in solvent-free conditions.

Pictet-Spengler based synthesis of a bisarylmaleimide glycogen synthase kinase-3 inhibitor

A practical synthesis of the glycogen synthase kinase-3 (GSK3) inhibitor bisarylmaleimide 1 has been accomplished employing Pictet-Spengler methodology to access the indole 7-position in preparing the benzodiazepine tricyclic fragment. A seven-step linear sequence that starts with commercially available 5-fluoroindole 7 affords the bisarylmaleimide 1 in 33% overall yield.