N-Pyrenylmethoxycarbonyl phototriggers for the release of serotonin, tryptamine and their biosynthetic precursors

An evaluation of the pyrenylmethoxycarbonyl group as a photolabile protecting group for the amino function, using neuroactive amines and amino acids as models, was carried out. 1-Hydroxymethylpyrene was reacted with serotonin and tryptamine and their corresponding amino acid precursors, L-5-hydroxytrypthophan and L-trypthophan, in the presence of N,N′-carbonyldiimidazole as carbonylating agent. Photolysis studies were carried out under irradiation at different wavelengths (250, 300, 350 and 419 nm), monitored by HPLC/UV and 1H NMR, and it was found that the carbamate bond between the active molecule and the pyrenylmethyl unit cleaved readily in short irradiation times. The results obtained at 350 nm irradiation are promising for practical purposes (4–20 min).Thanks are due to Fundação para a Ciência e Tecnologia (FCT) and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support through the Chemistry Research Centre of the University of Minho (Ref. UID/QUI/00686/2013 and UID/ QUI/0686/2016), project PTDC/QUI/69607/2006 (FCOMP-01-0124-FEDER-007449) and a PhD grant to M.J.G.F. (SFRH/BD/36695/2007). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT.