Direct Functionalization of Polyethylene Surfaces with High-Density Polymer Brushes.

Introducing functionality onto PE surfaces is a longstanding challenge in polymer science, driven by the need for polymer materials with improved adhesion and antifouling properties. Herein, we report surface-initiated hydrogen atom transfer-reversible addition-fragmentation chain transfer (SI HAT-RAFT) as a robust method to grow high-density brush polymers from PE surfaces. We demonstrate that, under mild conditions, direct initiation from the C-H bonds of PE surfaces allows for the graft polymerization of a variety of (meth)acrylate monomers. The resulting polymer brushes reached several hundred nanometers in thickness with densities of ca. 0.62 chains/nm2, compared to the current standard of ∼0.28 chains/nm2. Finally, we show that our method is capable of dramatically improving the adhesive properties of PE surfaces. This work enables the preparation of PE with diverse surface functionalities for potential use in biomedical, industrial, and battery applications.

DARK Classics in Chemical Neuroscience: Carfentanil.

Because of its remarkable potency and relative ease of synthesis, carfentanil (1) has recently emerged as a problematic contaminant in other drugs of abuse. Carfentanil and its close analogues, currently approved only for large animal veterinary medicine, have found use both as illicit additives to the clandestine manufacture of scheduled drugs and as chemical weapons. In this Review, the background, synthesis, manufacture, metabolism, pharmacology, approved indications, dosage, and adverse effects of carfentanil will be discussed along with its emergence as a key player in the ongoing opioid crisis.

Synthesis of Substituted 6,7-Dihydro-5H-pyrrolo[2,3-c]pyridazines/pyrazines via Catalyst-Free Tandem Hydroamination-Aromatic Substitution.

Herein, we report an efficient and operationally simple synthesis of 6,7-dihydro-5H-pyrrolo[2,3-c]pyridazines and 6,7-dihydro-5H-pyrrolo[2,3-b]pyrazines via a tandem hydroamination-SNAr sequence that makes use of mild reagents under catalyst-free conditions in moderate to high yields. This chemistry expands the known scope of pyridazine/pyrazine chemistry and can be applied toward the synthesis of novel drug-like molecules with favorable bioactivity and pharmacokinetic properties.