Polysquaramides.

Thermoplastics, while advantageous for their processability and recyclability, often compromise thermochemical stability and mechanical strength compared to thermosets. Addressing this limitation, we introduce an innovative approach employing reversibly cross-linked polymers, utilizing squaramide moieties to reconcile recyclability and robustness. Herein, we detail the synthesis of supramolecularly cross-linked polysquaramides through the condensation polymerization of diethyl squarate with primary and secondary diamines.

β-Triketones as Reactive Handles for Polymer Diversification via Dynamic Catalyst-Free Diketoenamine Click Chemistry.

The spontaneous condensation of amines with β-triketones (TK), forming β,β'-diketoenamines (DKE) and releasing water as the sole byproduct, exhibits many of the hallmarks of "click" reactions. Such characteristics render TKs as a highly advantageous platform for efficient polymer diversification, even in biological contexts. Leveraging reversible addition-fragmentation chain transfer (RAFT) and photoiniferter polymerization of novel TK-containing vinylic monomers, we synthesized polymers containing pendent TKs with excellent control of molecular weights, even in excess of 10 g mol.

Diversification of Acrylamide Polymers via Direct Transamidation of Unactivated Tertiary Amides.

Postpolymerization modification offers a versatile strategy for synthesizing complex macromolecules, yet modifying acrylamide polymers like poly(,-dimethylacrylamide) (PDMA) is notoriously challenging due to the inherent stability and low reactivity of amide bonds. In this study, we unveil a novel approach for the direct transamidation of PDMA, leveraging recent advances in the transamidation of unactivated tertiary amide substrates. By exploiting photoiniferter polymerization, we extended this direct transamidation approach to ultrahigh-molecular-weight (UHMW) PDMA, showcasing the unprecedented postpolymerization modification of synthetic polymers exceeding 10 g/mol.

Metallacyclobuta-(2,3)-diene: A Bidentate Ligand for Stream-line Synthesis of First Row Transition Metal Catalysts for Cyclic Polymerization of Phenylacetylene.

Described here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ -C,C-(Me SiC SiMe )}] (2-M) (BDI=[ArNC(CH )] CH , Ar=2,6- Pr C H ; M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl ] (1-M, M=Ti, V) with 1,3-dilithioallene [Li (Me SiC SiMe )]. Complexes 2-M have been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size-exclusion chromatography (SEC) and intrinsic viscosity studies.

Poly(Vinyl Ketones): New Directions in Photodegradable Polymers.

Poly(vinyl ketones) (PVKs) have received considerable attention over the past few decades due to their unique photochemistry and photodegradation properties under ultraviolet (UV) light. Many PVKs rapidly undergo photodegradation under UV light. The side-chain carbonyl moieties of PVKs permit photolysis through Norrish type I or Norrish type II reaction mechanisms and can also be readily modified by nucleophilic addition reactions.

Synthesis and Clinical Development of Palbociclib: An Overview.

Breast cancer is the second most commonly identified cancer in women in the United States after skin cancer. The past few years have seen a substantial increase in breast cancer awareness campaigns and active research in fields of diagnosis and targeted therapy. These factors have led to a better mechanistic understanding of the disease, detection at earlier stages, and a more personalized approach to treatment, ultimately causing a crucial increase in the survival rates after detection.

Water-Promoted Regiospecific Azidolysis and Copper-Catalyzed Azide-Alkyne Cycloaddition: One-Pot Synthesis of 3-Hydroxy-1-alkyl-3-[(4-aryl/alkyl-1H-1,2,3-triazol-1-yl)methyl]indolin-2-ones.

An efficient, eco-friendly, base free, one-pot, sequential protocol was developed for epoxide azidolysis and copper-catalyzed azide-alkyne cycloaddition using water as the solvent for the synthesis of 3-hydroxy-1-alkyl-3-[(4-aryl/alkyl-1H-1,2,3-triazol-1-yl)methyl]indolin-2-ones. The optimized reaction conditions have been generalized in the case of aromatic as well as aliphatic alkyne partners to afford good yields and high regioselectivity.