Browsing by Author "Rawal, Viresh H."

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EPR Imaging Spin Probe Trityl Radical OX063: A Method for Its Isolation from Animal Effluent, Redox Chemistry of Its Quinone Methide Oxidation Product, and in Vivo Application in a Mouse
(2016-12)
Serda, Maciej
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Wu, Yen-Ku
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Barth, Eugene D.
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Halpern, Howard J.
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Rawal, Viresh H.
We report herein a method for the recovery, purification, and application of OX063, a costly, commercially available nontoxic spin probe widely used for electron paramagnetic resonance (EPR) imaging, as well as its corresponding quinone methide (QM) form. This precious probe can be successfully recovered after use in animal model experiments (25-47% recovery from crude lyophilizate with 98.5% purity), even from samples that are >2 years old. Significantly, the recovered trityl can be reused in further animal model EPR imaging experiments. The work also describes support for the observed formation of an air-sensitive radical derived from the QM under reducing conditions.
Rapid construction of tetrahydropyridine scaffolds via formal imino Diels-Alder reactions of Schiff bases and Nazarov reagents
(2019-10-21)
Wu, Yen-Ku
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Rawal, Viresh H.
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應用化學系
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Department of Applied Chemistry
Described is a one-flask, two-step method for the synthesis of highly functionalized piperidines. The process involves formal [4 + 2] cycloadditions of Schiff bases and Nazarov reagents, followed by facile elaborations of the initial cycloadducts. Notably, these aza-annulations are facilitated by protic solvents and proceed smoothly under ambient conditions, without other additives. The synthetic utility of this annulation protocol is further showcased through a concise, convergent synthesis of (+/-)-tetrabenazine.