Silver-Catalyzed Skeletal Editing of Benzothiazol-2(3H)-ones and 2-Halogen-Substituted Benzothiazoles as a Rapid Single-Step Approach to Benzo[1,2,3]thiadiazoles
Jela Nociarová, Anisha Purkait, Róbert Gyepes, Peter Hrobárik*
*Department of Inorganic Chemistry, Faculty of Natural
Sciences, Comenius University, SK-84215 Bratislava, Slovakia, Email:
peter.hrobarikuniba.sk
J. Nociarová, A. Purkait, R. Gyepes, P. Hrobárik, Org. Lett., 2024, 26, 619-624.
DOI: 10.1021/acs.orglett.3c03904
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Abstract
A facile silver(I)-catalyzed reaction of benzothiazol-2(3H)-ones with NaNO2, or using AgNO2 directly, enables a single-step transformation to the corresponding benzo[1,2,3]thiadiazoles in good yields, with wide functional group compatibility. It can also be performed in a one-pot manner from readily available 2-halogen-substituted benzothiazoles.
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proposed mechanism
Details
The document discusses a novel silver(I)-catalyzed reaction for transforming benzothiazol-2(3H)-ones and 2-halogen-substituted benzothiazoles into benzo[1,2,3]thiadiazoles (iBTD) in a single step. This method, which uses NaNO2 or AgNO2, offers moderate to excellent yields and broad functional group compatibility. The transformation avoids the use of unstable 2-aminobenzenethiols, making it a more practical approach. The reaction can be performed in a one-pot manner and is inspired by genome-editing technologies, aiming to modify heteroaromatic substrates efficiently. The study highlights the importance of iBTD in pharmaceuticals and materials science, noting its scarcity in organic electronics due to synthetic challenges. The authors optimized the reaction conditions, achieving high yields and purity, and confirmed the structures of the products through NMR and HRMS spectra, as well as X-ray crystallography. The method's applicability extends to 2-bromothiazoles, although with lower success rates. Mechanistic studies suggest an ionic pathway involving N-nitrosation and ring-opening. This new approach could facilitate the discovery of biologically active substances and novel optoelectronic materials, with ongoing research in the authors' laboratory.
Key Words
benzo-fused S-heterocycles, benzo-fused N-heterocycles
ID: J54-Y2024