Unconventional stereoselective one-pot synthesis of Knoevenagel-type indoles via in situ condensation of iminium salts with active methylene reagents

One-pot synthesis and antiproliferative activity of highly functionalized pyrazole derivatives

A series of highly functionalized pyrazole derivatives has been prepared by a one-pot, versatile and regioselective procedure. Pyrazoles 1-29 were tested in cell-based assay to assess their antiproliferative activity against a panel of tumour cells. Additionally, the cytotoxicity of prepared compounds was evaluated against normal human fibroblasts. The antiproliferative activity of the synthesized molecules emerged to be affected by the nature of the substituents of the pyrazole scaffold and derivatives 21-23 proved to inhibit the growth of melanoma and cervical cancer cells. Compound 23 was identified as the most active derivative and docking simulations predicted its ability to interact with estrogen receptors.

Synthesis of novel polycarbonyl Schiff bases by ring-opening reaction of ethyl 5-acyl-4-pyrone-2-carboxylates with primary mono- and diamines

An approach for the introduction of the tricarbonyl moiety into aromatic, heterocyclic, and aliphatic amines with the use of acylpyrones has been developed for the synthesis and the design of novel polycarbonyl Schiff base ligands, including salphen structures. This Michael addition–ring-opening reaction proceeds under mild conditions (stirring at 0–20 °C) via the attack at the C-6 position of the pyrone ring in good to high yields (up to 99%) with excellent selectivity. The products can be easily isolated by crystallization without the use of chromatography. The scope of the reaction, tautomeric equilibrium of open-chain products, and their cyclization into pyridone structures were investigated.

An approach for the introduction of the tricarbonyl moiety into various amines has been developed based on acylpyrones.

Synthesis and biological evaluation of (acyl)hydrazones and thiosemicarbazones obtained via in situ condensation of iminium salts with nitrogen-containing nucleophiles

An unprecedented, highly convergent, high-yielding, one-pot synthesis of (acyl)hydrazones and thiosemicarbazones was carried out by the in situ condensation of isolable iminium chlorides of imidazolidin-2-(thio)one, tetrahydropyrimidin-2-thione and indole derivatives with nitrogen nucleophiles in the presence of a base. The developed reaction procedure is largely advantageous. It is highly parallelizable, no intermediates need to be isolated and minimal sample handling is required during the purification steps. Some relevant reaction parameters including reaction temperature and p[Formula: see text] of the base are discussed. NMR analysis was carried out to assess the stereochemistry of the obtained compounds. The stereochemical outcome of the reaction was found to be affected by the nature of the nitrogen-containing nucleophile being the majority of the derivatives isolated as single geometric isomers. The cytotoxicity and antiviral activities of the prepared compounds have been preliminary assessed. In cell-based screenings some of the derivatives proved to be cytotoxic at low micromolar concentrations and interesting anti-Reo-1 properties have been detected.