Abstract
N
-Acylbenzotriazoles enable the synthesis (69
–
92 % yield) of blue to green fluorescent coumarin-labeled depsidipeptides
8a–f
(quantum yields 0.004
–
0.97) and depsitripeptides
12a–d
(quantum yields 0.02
–
0.96). Detailed photophysical studies of fluorescent coumarin-labeled depsipeptides
8a–f
and
12a–d
are reported for both polar protic and polar aprotic solvents. 7
-
Methoxy and 7
-
diethylaminocoumarin
-
3
-
ylcarbonyl depsipeptides
8c,f
and
12d
are highly solvent sensitive. These highly fluorescent compounds could be useful for peptide assays. Further photophysical studies of 7
-
diethylaminocoumarin-labeled depsipeptides
8c,12d
within the micellar microenvironment of SDS reflect their ability to bind with the biological membrane, suggesting potential applications in the fields of bio- and medicinal chemistry.