TMSOTf-Mediated Formal [4 + 2] Cycloaddition-Retro-aza-Michael Cascade of Vinylogous Carbamates for the Synthesis of Highly Fluorescent Pyridocarbazoles
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Scale-up Chemical Synthesis of Thermally-activated Delayed Fluorescence Emitters Based on the Dibenzothiophene-S,S-Dioxide Core
Published on: October 24, 2017
Santosh J Gharpure1, Pankaj E Hande1, Surya K Pandey1
1Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
Abstract:
Trimethylsilyl trifluoromethanesulfonate mediated dimerization reaction of vinylogous carbamates of carbazoles gave highly fluorescent pyridocarbazoles through a Povarov-type formal [4 + 2] cycloaddition-retro-aza-Michael cascade. The developed strategy was used to access indolo pyridocarbazole and quinolizinocarbazolone in an expeditious manner. Various coupling reactions were successfully performed on synthesized pyridocarbazoles to study the effect of electronics of substitution on photophysical properties. Synthesized carbazoles possess excellent photophysical properties with high quantum yields (ΦF). Fluorescent carbazole dicarboxylic acid showed potential as a pH probe to give a linear response to pH over a very wide range (7.0-3.0) reflecting high efficiency.
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