Design, synthesis, and quantitative structure–activity relationship of cytotoxic γ-carboline derivatives

Synthesis and Biological Evaluation of Benzo [4,5]- and Naphtho[2',1':4,5]imidazo[1,2-c]pyrimidinone Derivatives

Azacarbazoles have attracted significant interest due to their valuable properties, such as anti-pathogenic and antitumor activity. In this study, a series of structurally related tricyclic benzo[4,5]- and tertacyclic naphtho[2',1':4,5]imidazo[1,2-c]pyrimidinone derivatives with one or two positively charged tethers were synthesized and evaluated for anti-proliferative activity. Lead tetracyclic derivative 5b with two amino-bearing arms inhibited the metabolic activity of A549 lung adenocarcinoma cells with a CC50 value of 3.6 μM, with remarkable selectivity (SI = 17.3) over VA13 immortalized fibroblasts. Cell-cycle assays revealed that 5b triggers G2/M arrest without signs of apoptosis. A study of its interaction with various DNA G4s and duplexes followed by dual luciferase and intercalator displacement assays suggests that intercalation, rather than the modulation of G4-regulated oncogene expression, might contribute to the observed activity. Finally, a water-soluble salt of 5b was shown to cause no acute toxic effects, changes in mice behavior, or any decrease in body weight after a 72 h treatment at concentrations up to 20 mg/kg. Thus, 5b is a promising candidate for studies in vivo; however, further investigations are needed to elucidate its molecular target(s).

Synthesis of novel indolo[3,2-c]isoquinoline derivatives bearing pyrimidine, piperazine rings and their biological evaluation and docking studies against COVID-19 virus main protease

A series of hybrid indolo[3,2-c]isoquinoline (δ-carboline) analogs incorporating two pyrimidine and piperizine ring frameworks were synthesized. Intending biological activities and SAR we propose replacements of fluorine, methyl and methoxy of synthetic compounds for noteworthy antimicrobial, antioxidant, anticancer and anti-tuberculosis activities. Among these compounds 3a, 4a and 5e were progressively strong against E. coli and K. pneumonia. Whereas, compounds 4a, 5a and 6a with addition of various functional groups (OCH₃, CH₃) were excellent against S. aureus and B. subtilis. Compound 5c exhibited strong RSA and dynamic ferrous ion (Fe²⁺⁾ metal chelating impact with IC₅₀ of 7.88 ± 0.93 and 4.06 ± 0.31 µg/mL, respectively. Compound 5e was considerably cytotoxic against all cancer cells displaying activity better than the standard drug. Compounds 6b and 6e inhibited M. tuberculosis (MIC 1.0 mg/L) considerably. Molecular docking studies indicate that compounds 4d, 5a, 5b, 6b and 6f exhibited good interactions with 6LZE (COVID-19) and 6XFN (SARS-CoV-2) at active sites. The structure of the synthesized compounds were elementally analyzed using IR, ¹H, ¹³C NMR and mass spectral information.

Discovery of hydrazide-based pyridazino[4,5-b]indole scaffold as a new phosphoinositide 3-kinase (PI3K) inhibitor for breast cancer therapy

The mono and dialkylation of pyridazino[4,5-b]indole with a set of alkylating agents were achieved. The synthesized pyridazino[4,5-b]indole hits have been evaluated and discovered as a new phosphoinositide 3-kinase (PI3K) inhibitor for breast cancer therapy.

Alkenyl Isocyanide Conjugate Additions: A Rapid Route to γ-Carbolines

Isocyanides are exceptional building blocks, the wide deployment of which in multicomponent and metal-insertion reactions belies their limited availability. The first conjugate addition/alkylation to alkenyl isocyanides is described, which addresses this deficiency. An array of organolithiums, magnesiates, enolates, and metalated nitriles add conjugately to β- and β,β-disubstituted arylsulfonyl alkenyl isocyanides to rapidly assemble diverse isocyanide scaffolds. The intermediate metalated isocyanides are efficiently trapped with electrophiles to generate substituted isocyanides incorporating contiguous tri- and tetra-substituted centers. The substituted isocyanides are ideally functionalized for elaboration into synthetic targets as illustrated by the three-step synthesis of γ-carboline N-methyl ingenine B.

A catalyst-free, efficient green MCR protocol for access to functionalized γ-carbolines in water

A catalyst-free green procedure for access to substituted γ-carbolines has been achieved in water with excellent yields via a MCR reaction of 3-formyl indole derivatives, aldehydes with NH₄OAc at room temperature under aerobic conditions.

Silver(i)-catalyzed annulation for the regioselective synthesis of N-imino-γ-carbolinium ylides from hydrazones of indole-3-carbonyl derivatives and propargylic alcohols

A regioselective efficient synthetic approach to N-imino-γ-carbolinium ylides via AgOTf-catalyzed iminoannulation from indole derivatives and propargylic alcohols has been developed.

Microbial transformation of azaarenes and potential uses in pharmaceutical synthesis

Pyridine, quinoline, acridine, indole, carbazole, and other heterocyclic nitrogen-containing compounds (azaarenes) can be transformed by cultures of bacteria and fungi to produce a variety of new derivatives, many of which have biological activity. In many cases, the microbial biotransformation processes are regio- and stereoselective so that the transformation products may be useful for the synthesis of new candidate drugs.