Photoinduced Release of Neurotransmitter Amino Acids from Coumarin‐Fused Julolidine Ester Cages

The photoinduced release of several neurotransmitter amino acids (glycine, alanine, glutamic acid, β‐alanine and γ‐aminobutyric acid) was accomplished from ester cages based on a new photoremovable protecting group consisting of a coumarin built on the julolidine nucleus, namely a (11‐oxo‐2,3,5,6,7,11‐hexahydro‐1 H ‐pyrano[2,3‐ f ]pyrido[3,2,1‐ ij ]quinolin‐9‐yl)methyl group. Photolysis and steady‐state sensitization studies revealed that release of the active molecule occurred in short irradiation times at long wavelengths, with a very promising performance at 419 nm. Given the interest in the development of novel protecting groups that are cleavable with UV A or even visible radiation, it was found that a structural modification in the coumarin ring by assembly of a fused julolidine leads to a promising photolabile protecting group for organic synthesis and also for bioapplications.