Chiral Isochalcogenourea Lewis Base Organocatalysis
Mario Waser
Johannes Kepler University Linz,  Austria

Abstract:
Chiral Isochalcogenoureas (IChU) are versatile Lewis base (LBs) organocatalysts that allow for numerous highly enantioselective transformations. Over the last years our group had a strong interest in the utilization of these chiral LBs for the covalent activation, control and utilization of simple carboxylic acid derivatives (via in situ C1 ammonium enolate formation) and allenoates (via in situ betaine formation).Furthermore, we are also interested in the design and use of new catalyst derivatives and in the elucidation of their key properties such as nucleophilicity and basicity. In this presentation I will give an overview of our most recent results focusing on the development and mechanistic understanding of new catalysts and new transformations.

Selected recent contributions related to this topic:
  - M. Piringer, A. Scheucher, M. Hofer, M. Bechmann, A. R. Ofial, L. Stockhammer, Mario Waser ChemistryEurope., 2026, 4, e202500443.
  - L. Stockhammer, K. Kasten, A. Eitzinger, L. S. Vogl, M. Piringer, D. Weinzierl, A. R. Ofial, A. D. Smith, Mario Waser Angew. Chem. Int. Ed., 2025, 64, e202514865.
  - Lukas S. Vogl, Peter Mayer, Raphael Robiette, Mario Waser Angew. Chem. Int. Ed., 2024, 63, e202315345.
  - Magdalena Piringer, Mario Hofer, Lukas S. Vogl, Peter Mayer, Mario Waser Adv. Synth. Catal. 2024, 366, 2115-2122.
  - David Weinzierl, Magdalena Piringer, Paul Zebrowski, Lotte Stockhammer, Mario Waser Org. Lett., 2023, 25, 3126-3130.
  - Lotte Stockhammer, Rebecca Craik, Uwe Monkowius, David B. Cordes, Andrew D. Smith, Mario Waser ChemistryEurope, 2023, 1, e202300015

Multi-target Anti-infectives Based on Quinoline Scaffolds
Josef Jampilek
1. Palacky University Olomouc, Czech Republic;
2. University of Silesia, Poland

Abstract:
Multi-target agents are chemical entities designed to interact with two or more biological targets that are crucial for the mechanism or progression of a disease. This innovative strategy contrasts with the traditional “one drug, one target” paradigm of drug discovery. This approach is based on the concepts of privileged structures, polypharmacology, and multifactorial diseases. It appears to be a generally useful tool in the design of anti-invasive (anti-infective, anti-cancer) drugs, as the therapeutic agents designed in this way interact with multiple targets, so that they are able to destroy both sensitive and resistant pathogens/cells while also preventing their emergence. Multi-target anti-infectives thus represent compounds resistant to resistance.

In modern molecular architecture, heterocyclic systems represent privileged scaffolds. According to statics, heterocycles constitute more than 85% of biologically active molecules. This phenomenon is not accidental; heterocycles provide an ideal balance between the rigidity necessary for molecular recognition and the chemical diversity that allows interactions with a wide range of biological targets.

Quinoline-based compounds have various promising biological properties and therefore have received special attention in the field of drug design and medicinal chemistry. The quinoline scaffold can be easily and rapidly synthesized and functionalized, which indicates the importance of this privileged structure. Moreover, this simple structural element has unique physicochemical properties and allows for a large number of target- or diversity-oriented modifications.

This contribution focuses on the investigation of ring-substituted hydroxy- and aminoquinolines and their antifungal, antibacterial, antimycobacterial and antiprotozoal activities.

Design of Chemically Recyclable Biobased Aliphatic Polyesters
Kotohiro Nomura
Tokyo Metropolitan University, Japan

Abstract:
Development of recyclable functional polymers from renewable feedstocks has been recognized as an important subject in the field of polymer chemistry and green sustainable chemistry.  Biobased polyesters derived from plant resources thus attract considerable attention [1] in terms of circular economy due to facile ability of chemical recycling compared to conventional polyolefins.  

Our laboratory focuses on synthesis of biobased aliphatic polyesters by acyclic diene metathesis (ADMET) polymerization and the subsequent hydrogenation [2,3], in particular we developed synthesis of high molar mass polyesters by using molybdenum-alkylidene catalysts or ruthenium-carbene catalysts in ionic liquid.  The tensile properties (tensile stress and strain at break) in the resultant polymer films increased upon increase in the Mn value, and the polymer films with high molar mass samples (Mn = ca. 50,000) exhibit better tensile properties than conventional polyolefins [3a].  Thermal properties were affected by the monomer repeat units [2,3], and the end groups.

More recently, we have developed chemically recyclable biobased poly(ester amide)s displaying promising both tensile and self-healing properties [4]; both the thermal and tensile properties were dependent upon the amino acid fragment employed as well as the molecular weights.  These polymers were easily depolymerized through transesterification using our catalysis.

Moreover, we also developed new catalysts for acid-, base-free depolymerization of various polyesters by transesterification with alcohol [5,6].  The reaction proceeds in exclusive selectivity with quantitative conversion.  The method thus enabled to proceed one-pot closed-loop chemical recycling through depolymerization‒repolymerization.

References
1. Nomura, K.; Awang, N. W. B. ACS Sustainable Chem. Eng. 2021, 9, 5486.
2. Nomura, K. et al. ACS Omega 2020, 5, 18301; 2023, 8, 7222; 2024, 9, 9109; 2026, 11, 12779; ACS Polym. Au 2025, 5, 241.
3. Nomura, K. et al. (a) ACS Macro Lett. 2023, 12, 1403. (b) Biomacromolecules 2025, 26, 6731.
4. Miyamoto, G.; Abdellatif, M. M.; Higashi, S.; Tao, K.; Takeshita, H.; Hirano, H.; Nomura, K. JACS Au 2026, 6, 3990.
5. (a) Nomura, K.; Aoki, T.; Ohki, Y.; Kikkawa, S.; Yamazoe, S. ACS Sustainable Chem. Eng. 2022, 10, 12504. (b) Ohki, Y.; Ogiwara, Y.; Nomura, K. Catalysts 2023, 13, 421. (c) to be published.
6. (a) Awang, N. W. B.; Hadiyono, M. A. B. R.; Abdellatif, M. M.; Nomura, K. Ind. Chem Mat. 2025, 3, 49. (b) Jiang, Y.; Jaiyen, K.; Abdellatif, M. M.; Nomura, K. ACS Sustainable Resour. Manage. 2025, 2, 2397.

Ohmic heating as a strategy for upcycling PET plastic waste for new supramolecular structures
Ana Margarida Gomes da Silva
University of Porto, Portugal

Abstract:
Plastic waste, particularly from poly(ethylene terephthalate) (PET) used in bottles and packaging, is a growing environmental challenge. Developing effective strategies to recycle and transform this waste into valuable products is essential for a more sustainable future. In this study, terephthalic acid (TPA), one of the main building blocks of PET, was recovered through alkaline hydrolysis of PET waste under ohmic heating conditions and compared with conventional and microwave heating methods. Different types of PET waste, including both white and colored PET bottles, were successfully processed, and analytical techniques confirmed the recovery of high-purity TPA.

The recovered TPA was subsequently used to synthesize new crystalline materials through combination with 4-(dimethylamino)pyridine and 4-aminopyridine, yielding compounds 1 and 2. These compounds were characterized by microscopy and X-ray diffraction techniques. Detailed structural analysis revealed that compound 1 forms a robust three-dimensional network stabilized by ionic and hydrogen-bonding interactions.

The results demonstrate that ohmic heating is a promising approach for PET hydrolysis. Furthermore, the successful synthesis of supramolecular architectures highlights the potential of recycled TPA as a valuable building block for advanced functional materials, providing a promising route for the high-value upcycling of PET waste.