Title

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

Subject Area

ARRAY(0x55736f696fb8)

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

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