Dediazoniative functionalization of chromen-4-one and chromen-2-one diazonium-BF4 salts in BMIM-ILs. direct access to the [sbnd]F, [sbnd]I, [sbnd]OSO(CF3)[dbnd]NTf, and [sbnd]N(Tf)2 derivatives, and facile synthesis of chromenone azo-dyes by coupling to activated arenes
Document Type
Article
Publication Date
7-30-2020
Abstract
Chromenone-diazonium-BF4 salts were isolated as stable powders by diazotization of the 7-amino-derivatives with NaNO2/HBF4. The 7-Fluoro-derivatives were synthesized by fluorodediazoniation in [BMIM][PF6], while the 7-iodo-derivatives were obtained by iododediazoniation with TMSI/[BMIM][PF6]. Further iodination with NIS furnished the 2,7-di-iodo derivative. Dediazoniation in [BMIM][Tf2N] gave the corresponding chromenone-OSO(CF3)[dbnd]NTf compounds as major products, along with chromenone[sbnd]N(Tf)2 and the 7-fluoro-derivatives. Chromenone-diazonium salts undergo facile diazo-coupling with isomeric trimethoxybenzenes and dimethylaniline at r.t in aqueous EtOH or in [BMIM][PF6] to give azo-dyes.
Publication Title
Tetrahedron Letters
Volume
61
Issue
31
Digital Object Identifier (DOI)
10.1016/j.tetlet.2020.152179
ISSN
00404039
E-ISSN
18733581
Citation Information
Luisa F. Gutierrez, L. F. Gutierrez, Yuki Agemura, Y. Agemura, & Kenneth K. Laali, K. K. Laali. (0000). Dediazoniative functionalization of chromen-4-one and chromen-2-one diazonium-BF4 salts in BMIM-ILs. direct access to the [sbnd]F, [sbnd]I, [sbnd]OSO(CF3)[dbnd]NTf, and [sbnd]N(Tf)2 derivatives, and facile synthesis of chromenone azo-dyes by coupling to activated arenes. Tetrahedron letters, 61, 152179. doi: 10.1016/j.tetlet.2020.152179