2989
Having established a successful synthesis of this system we investigated its coupling reaction with a
glycosyl donor having an anomeric propane-1,3-diylphosphate as a leaving group. Thus, treatment of 18,
with the phosphate 8 in the presence of trimethylsilyl triflate, gave the β-glycoside 9 in 69% yield. The
glycoside 9 proved to be a highly yellow fluorescent material that had absorption maxima at 427, 333,
233 nm (Scheme 2).
Scheme 2.
In summary, we have established that Suzuki coupling of the bromoaromatic anhydride can be
employed to afford biaryl systems that can be elaborated to afford novel oxoxanthenoisoquinoline which
is an excellent fluorophore.
Acknowledgements
We thank the EPSRC for access to mass spectrometry service at the University of Wales, Swansea
(Director, Professor D. E. Games).
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8. Selected data: compound 1: m.p. 171–173°C, νmax (KBr) 3650, 1731 cm−1; λmax (MeOH) 438 (ε 3540), 332 (ε 2313), 284
(ε 4415), 260 (ε 4670) nm; δH (270 MHz, CDCl3), 1.59 (1H, brs), 3.96 (2H, dd, J=5.3, 4.3 Hz), 4.43 (2H, app. t, J=5.3 Hz),
7.02 (1H, dd, J=8.59, 6.6 Hz), 7.11 (1H, d, J=6.6 Hz), 7.39 (1H, ddd, J=7.9, 7.9, 7.3 Hz), 7.67 (1H, dd, J=7.9, 7.3 Hz), 7.74