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Graphical abstract Highlights • A one pot protocol for the synthesis of quaternary α-aminosuccinimides. • Ferric Nitrate promote imidazo[1,2-a]pyridine structural metamorphosis. • A potential way to synthesize α-aromatic ring substituted quaternary amino acids. Abstract An efficient protocol has been accomplished for the synthesis of quaternary α-aminosuccinimides in toluene medium involving 2-phenylimidazo[1, 2-a]pyridine in a one-pot reaction promoted by Ferric Nitrate at 120 °C. The protocol presented herein, is for the first time, via a novel transformation where Ferric Nitrate promotes imidazo[1,2-a]pyridine structural metamorphosis to the title compound quaternary succinimides. High compatibility, easy work-up, and excellent yields are the advantages of this protocol. The quaternary α-aminosuccinimides are expected to have great potential in synthesizing quaternary α-amino acids and applications in medicinal chemistry. [ABSTRACT FROM AUTHOR]

• Efficient radiosynthetic route to a 18F-labeled M4 PET ligand. • High radiochemical yield and high molar activity. • Modest in vitro binding specificity by autoradiography studies. • Limited brain penetration in rodents. Positive allosteric modulators of muscarinic acetylcholine receptor subtype 4 have been identified as promising activators for the treatment of neurological disorders and neurodegenerative diseases, including schizophrenia, Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). Herein we report the synthesis and preliminary evaluation of a 18F-labeled positron emission tomography ligand based on a M 4 activator (7). 18F-Isotopologue of 7 was prepared in a reasonable radiochemical yield with high radiochemical purity (>99%) and high molar activity (>37 GBq/µmol). In vitro autoradiography studies indicated that the ligand possessed moderate in vitro specific binding. Dynamic PET studies in vivo demonstrated that 18F] 7 (also named as 18F]M 4 R-1911) failed to cross the blood–brain barrier. Therefore, further chemical scaffold optimization in chemotype of 7 is necessary to overcome limited brain permeability and improve specific binding. [ABSTRACT FROM AUTHOR]