A Mild and Efficient Method for the N-Debenzylation of Aromatic Heterocycles
Haddach, A. A.;1 Kelleman, A.;2 Deaton-Rewolinski, M. V.1
1Agouron Pharmaceuticals, Inc., A Pfizer Company, Chemical Research & Development, 3565 General Atomics Court, San Diego, CA 92121, 2University of California, San Diego.
A procedure for the N-debenzylation of aromatic heterocycles was reported. The procedure involves preparation of solution of the substrate in DMSO (0.1 M) with KOtBu (7.0 equivalents), followed by bubbling oxygen through the solution until the starting material has been consumed. Examples of the substrates reported are N-benzyl -indoles, -imidazoles, -indazoles, pyrazoles benzimidazoles, and -carbazoles. Yields are reported to range from 82% to quantitative conversion. A proposed mechanism is shown in
Scheme 10.
Proposed Mechanism for N-Debenzylation
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000265591-file_kvmw.gif)
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