A novel unsymmetrical phthalimide-containing phthalonitrile was synthesized and showed excellent thermal properties. A nucleophilic addition mechanism was introduced to explain the different reactivities of active H-containing heterocyclic structures toward phthalonitrile.

Further enriching the source of bio-based raw materials for thermosets is of significant importance in the current development context. In this paper, we synthesized a novel bio-based phthalonitrile monomer derived from L-tyrosine to verify the feasibility of a bio-based L-tyrosine molecular design platform for thermosets, and to prove that the L-tyrosine building-block can confer high performance. The biomass content of L-tyrosine-based phthalonitrile monomer reaches 56%, higher than other bio-based phthalonitrile resins. The structure was confirmed by ¹H NMR, ¹³C NMR, Fourier-Transform Infrared Spectroscopy (FTIR) and elemental analyses. The curing behavior was investigated by FTIR spectra, differential scanning calorimetry (DSC) and in situ FTIR spectra. The processability was studied by rheological analysis. And a study of the curing kinetics of the TPN monomer was carried out by non-isothermal DSC. Finally, the physical properties of the cured polymer were evaluated by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The results indicate that the phthalonitrile resin exhibited a high glass transition temperature (T_g) and excellent thermal properties compared with petroleum-based bisphenol A phthalonitrile resin. The results also demonstrate that introducing L-tyrosine into thermosets is feasible and can simultaneously impart excellent performances to the materials with relatively high level of biomass.

Targeting “undruggable” targets with intrinsically disordered structures is of great significance for the treatment of disease. The transcription factor c‐Myc controls global gene expression and is an attractive therapeutic target for multiple types of cancers. However, due to the lack of defined ligand binding pockets, targeted c‐Myc have thus far been unsuccessful. Herein, to address the dilemma of lacking ligands, an efficient and high throughput aptamer screening strategy is established, named polystyrene microwell plate‐based systematic evolution of ligands by exponential enrichment (microwell‐SELEX), and identify the specific aptamer (MA9C1) against c‐Myc. The multifunctional aptamer‐based Proteolysis Targeting Chimeras (PROTAC) for proteolysis of the c‐Myc (ProMyc) is developed using the aptamer MA9C1 as the ligand. ProMyc not only significantly degrades c‐Myc by the ubiquitin‐proteasome system, but also reduces the Max protein, synergistically inhibiting c‐Myc transcriptional activity. Combination of the artificial cyclization and anti‐PD‐L1 aptamer (PA1)‐based delivery system, circular PA1‐ProMyc chimeras achieve tumor regression in the xenograft tumor model, laying a solid foundation for the development of efficacious c‐Myc degrader for the clinic. Therefore, this aptamer‐based degrader provides an invaluable potential degrader in drug discovery and anti‐tumor therapy, offering a promising degrader to overcome the challenge of targeting intractable targets.