Direct Iodination of Electron-Deficient Benzothiazoles: Rapid Access to Two-Photon Absorbing Fluorophores with Quadrupolar D‑π-A-π‑D Architecture and Tunable Heteroaromatic Core
journal contributionposted on 22.04.2021, 19:51 authored by Jela Nociarová, Patrik Osuský, Erik Rakovský, Dimitris Georgiou, Ioannis Polyzos, Mihalis Fakis, Peter Hrobárik
Direct iodination of benzothiazoles under strong oxidative/acidic conditions leads to a mixture of iodinated heteroarenes with 1–2 major components, which are easily separable and which structures depend on the I2 equivalents used. Among the unexpected but dominant products were identified 4,7-diiodobenzothiazoles with a rare substitution pattern for SEAr reactions of this scaffold. These were employed in the synthesis of 4,7-bis(triarylamine-ethynyl)benzothiazoles a new class of highly efficient quasi-quadrupolar fluorophores displaying large two-photon absorption cross sections (540–1374 GM) in the near-infrared region.
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S E Ar reactions2 equivalentsQuadrupolarquasi-quadrupolar fluorophoresElectron-Deficient BenzothiazolesTwo-PhotondiiodobenzothiazolescaffoldRapid Accessheteroarenenear-infrared regionbenzothiazolesynthesismixturecomponentbioxidativeGMiodinationTunable Heteroaromatic CoreDirect Iodinationsectionsubstitution patternFluorophoretwo-photon absorption