The method for the synthesis of complex alkaloid-like aza-heterocycles has been developed through the Povarov reaction of in situ generated 2-oxoimidazolium cations. The reaction lead to the formation of 2 C–N, 2 C–C bonds and three stereocentres, and features excellent regio- and diastereoselectivity. Based on the controlled experiments and quantum chemistry data, the mechanism of the reaction cyclization was proposed and diastereoselectivity origins were rationalized. Additionally, a straightforward synthesis of hardly accessible 4,4′-bi(imidazol-2-one) derivatives has been achieved using the same methodology.

The cooperative L-proline/Brønsted acid/base promoted reaction of 2-ethoxypyrrolidines or N-substituted 4,4-diethoxybutan-1-amines with methyl(alkyl/aryl)ketones for the synthesis of 2-(acylmethylene)pyrrolidine derivatives is reported. The key features of the developed protocol are gram-scale synthesis of the target compounds, easily available starting materials, operational simplicity and usage of non-expensive reagents.

We report a diastereospecific method for the synthesis of phosphorus-containing pyrrolizidines based on the cyclization of 3-arylidene-1-pyrrolinium containing an alkyltriphenylphosphonium salt fragment catalyzed by sodium ethylate and water.

Background/Objectives: The development of antitumor agents possessing low toxicity against non-cancerous cells is still a challenge in medicinal chemistry. In this paper, we report the antitumor activity of “hybrid structures” derived from the amino acid taurine. We have synthesized 26 compounds, structures of which were confirmed using NMR, X-ray diffractometry, and other techniques. Cytotoxicity of the obtained compounds has been evaluated using three human cancer cell lines. Pyrrolidine 4p has exhibited the strongest antiproliferative activity against HL-60 cells with an IC₅₀ of 76.7 μM, while IC₅₀ against normal cells was 176.3 μM. Water-soluble derivatives of taurine have been tested for antileukemia activity in mice of the BDF1 line. Compound 4p has been identified as the leading compound, which increases the mean survival time of mice from 40 to 100% as compared to the control group. Together, these results prove that taurine-based hybrid structures can be a promising scaffold for the discovery of potential antiproliferative agents.