Because allopregnanolone and derivatives represent biologically active molecules, in this letter, we present the synthesis of a new bioconjugate steroid pyridinium salt derived from allopregnanolone in three steps. The key steps involve the formation of the hydrazone intermediate, followed by condensation with bromoacetyl bromide and subsequent coupling with pyridine to generate the pyridinium bromide salt. The new bioconjugate steroid pyridinium salt, 4, was fully characterized by proton and carbon nuclear magnetic resonance (¹H and ¹³C NMR) spectroscopy, mass spectrometry (MS), and Fourier transform infrared spectroscopy (FTIR). ¹H-NMR analysis revealed the presence of a dynamic rotameric mixture in a 7:3 ratio of Z/E amide conformers, which were identified by a 2D NOESY experiment.

The first diastereoselective synthesis of (−)-1-epi-lentiginosine from a common chiral trans-epoxyamide derived from 2-pyridincarbaldehyde is reported. This methodology involves a sequential oxirane ring opening and intramolecular 5-exo-tet cyclization of tosylate trans-epoxyalcohol to afford a diastereomeric mixture of indolizinium salts in a one-pot fashion, followed by regio- and diastereospecific pyridinium ring reduction.

In this work, we describe the synthesis of chiral (R)-(‒)-piperidine-2,4-dione derived from (R)-(‒)-phenylglycinol, a valuable building block for the diastereoselective synthesis of piperidine alkaloids. The key step involves intramolecular cyclization: when the electrophile is an ester, the reaction proceeds via the formation of a Grignard intermediate, whereas when the electrophile is a nitrile, the cyclization follows a Blaise-type mechanism.

Background: Chiral azepines are synthesized with remarkable diastereoselectivity, but their biological activity has not been investigated. However, benzazepines have demonstrated notable effects, particularly on the central nervous system (CNS) and infections. This characteristic attracts the interest of bioinformatic investigations in this new family, as their structural similarity can confirm their potential based on their kinship or discovering new options for biological potential. Objective: Possible interaction targets of previously synthesized chiral azepines are investigated. This study involves examining the interaction between these targets, conducting molecular docking analysis, ADME (administration, distribution, metabolism, excretion), and toxicology prediction to assess biological potential. Methods: Modeling 3D-optimized structural, virtual screening, molecular docking, ADME, and toxicological studies were performed. Results: Structural analysis demonstrated potential against neurodegenerative diseases and cancer. In Molecular docking against cancer, pathways dependent on MAP2K1 and COX-2 exhibited energetically superior inhibitors than reference drugs, namely azepines 1, 3, and 6. Additionally, azepines 1 and 8 exhibited selective impacts against GSK3 and HMG-CoA-Reductase, respectively. Azepine 6 demonstrated an effect on CNS vs. GSK3 and HMG-CoA-Reductase, as well as potential against Alzheimer's disease; however, with a lower energy level with subunit 33 GABA-receptor. ADMETx investigations indicated satisfactory results for azepines. However, the opening of the cycle results in adverse effects and increased bioaccumulation, indicating the importance of preserving the integrity of azepine to propose its biological effect. Conclusion: Chiral azepines exhibit significant biological potential, particularly azepine 6 with a methyl substituent, which demonstrates multitarget potential. In addition, p-nitro phenyl substituent makes it highly selective towards CNS diseases. These findings indicate a strong relationship between biological activity and the stability of chiral azepines.

The first diastereoselective synthesis of (–)-1-epi-lentiginosine stars from a common chiral trans-epoxyamide derived from 2-pyridincarbaldehyde is reported. This methodology involves a sequential oxirane ring opening and intramolecular 5-exo-tet cyclization of tosylate tras-epoxyalcohol to afford a diastereomeric mixture of indolizinium salts in a one-pot fashion, followed by regio- and diastereospecific pyridinium ring reduction.