Development of a temporary marker for peptides

3-[(N,N-dimethylaminophenyl)-4'-diazenyl]-benzoic acid was coupled with several amino acid esters and the product further acylated with Boc. The material thus obtained was then submitted to cleavage by electrolysis and nucleophilic attack in order to evaluate the possibility to use this chromophore as a temporary marker

Bifunctionalised long-wavelength fluorescent probes for biological applications

The synthesis of benzo[a]phenoxazinium chlorides which are bifunctionalised in position 2 with 4-ethoxy-4-oxobutoxyl, 3-hydroxypropoxyl or 3-chloropropoxyl groups, and in position 9 with the (aminopropyl)amino group, was efficiently performed. The covalent labeling of valine was carried out by using one of the new fluorophores obtained. Photophysical studies in the homogeneous media of ethanol, distilled water and at simulated physiological conditions revealed that all the compounds absorbed and emitted from 610 to 651 nm.Fundação para a Ciência e Tecnologia (FCT, Portugal) - financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU - financial support to the Research Centre, CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)]

Synthesis and spectral characterization of a fluorescent marker

A fluorescent naphtofuran was synthetized from benzopyran by alcaline ring contraction and coupled to the α-amine group of various amino acids, in order to evaluate its applicability as a fluorescent marker for biomolecules. Fluorescence data was collected for all derivatives.Fundação para a Ciência e Tecnologia

Photolytic release at different wavelengths of tetrapeptide AAPV from a pyrenylmethyl conjugate

Comunicação em painel no 2nd Symposium on Medicinal Chemistry, Braga, Portugal, 8 Maio 2015The present work describes the photolysis of ester conjugate NH2-Ala-Ala-Pro-Val-Pym, with Pym being the pyrenylmethylene group, at different wavelengths of irradiation in different solvents and simulated physiological environment. The photolysis of the ester conjugate and the release of the free tetrapeptide was monitored by HPLC with UV detection, with collection of kinetic data.Fundação para a Ciência e Tecnologia(FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE -QREN-EU for financial support to Research Centre of Chemistry, CQ/UM [PEst -C/QUI/UI0686/2013 (FCOMP-01-0124-FEDER-037302)]info:eu-repo/semantics/publishedVersio

A naphtho[2,1-b]furan as a new fluorescent label: synthesis and spectral characterisation

A fluorescent naphthofuran was synthesised from an oxobenzopyran by alkaline ring contraction and coupled with various L-amino acids at their N-terminus or at side-chain functional groups, in order to evaluate its applicability as a fluorescent label for biomolecules and in peptide synthesis. Fluorescence data were collected for all derivatives, which were found to be moderately fluorescent and having moderate to good fluorescence quantum yields.Thanks are due to the Foundation for Science and Technology (Portugal) for financial support through Centro de Química (UM)

A photolabile prodrug of tetrapeptide AAPV bearing 7-methoxycoumarin at the C-terminal

Comunicação em painel QS30 no livro de resumos do XX Encontro Luso-Galego de Químicathe present work describes the evaluation as a photolabile prodrug of a fluorescent conjugate of the tetrapeptide AAPV labeled at the C-terminus with 7-methoxycoumarin. This conjugate was submitted to photocleavage studies at different wavelengths of irradiation in different solvents and simulated physiological environment in order to study the release of the peptide. The photolysis process was monitored by HPLC with UV detection and 1H NMR, with collection of kinetic data.Fundação para a Ciência e a Tecnologia (FCT

Oxazole light triggered protecting groups: synthesis and photolysis of fused heteroaromatic conjugates

Fused oxazole derivatives were synthesized and evaluated as new light triggered protecting groups by using amino acids as model bifunctional molecules. The photosensitivity of ester conjugates was tested under irradiation at 254, 300, and 350 nm. Oxazole conjugates were readily photolyzed with complete release of the amino acid, the best results obtained for naphtho[2,3-d]oxazole at 254 and 300 nm, being the first reported application of this type of heterocycles as photocleavable protecting groups for carboxylic acids.Thanks are due to the Foundation for Science and Technology (Portugal) for financial support through project PTDC/QUI/69607/2006 (FCOMP-01-0124-FEDER-007449) and Centro de Quimica (Universidade do Minho). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased in the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT

Photoactivable oxobenzopyranoxazole esters of 5-aminolevulinic acid

Comunicação em painel P51 no 1st European Young Chemists Meeting/ 5th Portuguese Young Chemists Meeting, Guimarães, Portugal, 26-29 Abril 2016.In this communication we report the synthesis of new oxobenzopyranoxazoles 1a,b as photolabile protecting groups and their conjugation with 5-(N-butyloxycarbonyl)aminolevulinic acid 2 via an ester bond. The study of the photolytic behaviour of the resulting conjugates in different conditions was carried out in a photochemical reactor by irradiation at 254, 300, 350 and 419 nm, monitored by HPLC-UV and 1H NMR.Thanks are due to the Foundation for Science and Technology (Portugal) for financial support through project PEstC/QUI/UI0686/2013 (F-COMP-01-0124-FEDER-037302) FEDER-COMPETE, FCT-Portugal. A PhD grant to A.M.S.S. (SFRH/BD/80813/2011) is also acknowledged. The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased in the framework of the National Program for Scientific Reequipment, with funds from POCI 2010 (FEDER) and FCT.info:eu-repo/semantics/publishedVersio

Acridinyl methyl esters as photoactive precursors in the release of neurotransmitter amino acids

An investigation of the use of an azaheterocycle, acridine, as an alternative photochemically removable protecting group for the carboxylic function of neurotransmitter amino acids was carried out. 9-Bromomethylacridine was used in the reaction with glycine, alanine, glutamic acid, β-alanine and γ-aminobutyric acid, to obtain model ester derivatives, which were irradiated at different wavelengths in a photochemical reactor. The process was followed by HPLC/UV, resulting in the release of the active molecule in short irradiation times. The results obtained using 419 nm irradiation show promise (35-98 min) for practical purposes. The compounds were further characterised via time-resolved fluorescence to elucidate their photophysical properties and determine the decay kinetics.Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the research centre CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)] and project PTDC/QUI/69607/2006 (FCOMP-01-0124-FEDER-007449). FCT - a PhD grant to A.M.P. (SFRH/BD/61459/2009)