Light-induced rearrangement from macrocyclic to bicyclic lactam: A case study of -chlorinated laurolactam.

Converting macrocycle lactams into bicyclic lactams is proposed as an additional way to further increase the metabolic stability of peptide-based drugs. Unfortunately, the synthesis of bicyclic lactams has to start almost from scratch. This study explores the Hofmann-Löffler-Freytag (HLF) reaction mechanism and products as a potential late-stage functionalisation strategy for facile conversion of macrocyclic to bicyclic ring.

Unveiling the antiglioblastoma potential of harmicens, harmine and ferrocene hybrids.

The poor prognosis of glioblastoma multiforme, inadequate treatment options, and growing drug resistance urge the need to find new effective agents. Due to the significant anti-cancer potential of harmicens, hybrid compounds which comprise harmine/β-carboline and ferrocene moiety, we investigated their antiglioblastoma potential and mechanism of action (inhibition of DYRK1A, Hsp90, anti-oxidative activity). The results have shown that triazole-type harmicens, namely , with a ferrocene moiety in C-3 position of the β-carboline ring ( = 3.

Regioselective Rearrangement of Nitrogen- and Carbon-Centered Radical Intermediates in the Hofmann-Löffler-Freytag Reaction.

The Hofmann-Löffler-Freytag (HLF) reaction serves as a late-stage functionalization technique for generating pyrrolidine heterocyclic ring systems. Contemporary HLF protocols utilize in situ halogenated sulfonamides as precursors in the radical-mediated rearrangement cycle. Despite its well-established reaction mechanism, experiments toward the detection of radical intermediates using EPR techniques have only recently been attempted.

Semiconductive 2D arrays of pancake-bonded oligomers of partially charged TCNQ radicals.

Multicentre two-electron (mc/2e or 'pancake bonding') bonding between 7,7,8,8-tetra-cyano-quinodi-methane (TCNQ) radical anions was studied on its 14 novel salts with planar organic cations. The formal charges of the TCNQ moieties are -1/2 and -2/3, and they form mc/2e bonded dimers, trimers and tetramers which are further stacked into extended arrays. Multicentre bonding within these oligomers is characterized by short interplanar separations of 2.

A quantum many body model for the embedded electron spin decoherence in organic solids.

We present a generalized nuclear spin bath model for embedded electron spin decoherence in organic solids at low temperatures, which takes the crucial influence from hindered methyl group rotation tunneling into account. This new, quantum many body model, after resolved using the cluster correlation expansion method, predicts the decoherence profiles directly from the proton relative position and methyl group tunneling splitting inputs. Decoherence profiles from this model explain adequately the influence from both strongly and weakly hindered methyl groups to embedded electron spin decoherence: The former accelerates decoherence by increasing the nearest neighbor nuclear spin coupling, while the latter enhances coherence through a novel confinement like' mechanism, in which the very strong nuclear spin coupling from the tunneling splitting term suppresses those protons on the methyl rotors from participating in the bath dynamics.

Matrix material structure dependence of the embedded electron spin decoherence.

In this article, we present the novel application of the nuclear spin bath model and the cluster correlation expansion method on studying the matrix material structure via embedded electron spin decoherence. Profiles of embedded electron spin decoherence under the Carr-Purcell-Meiboom-Gill dynamical decoupling pulse series in a model system for organic solids (malonic acid) are calculated for different structures. Resulting decay profiles exhibit a strong correlation to the variations of an adjacent proton environment among them.