Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study

Alkylation patterns and excited-state properties of pterins were examined both experimentally and theoretically. 2D NMR spectroscopy was used to characterize the pterin derivatives, revealing undoubtedly that the decyl chains were coupled to either the O4 or N3 sites on the pterin. At a temperature...

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Detalles Bibliográficos
Autores principales:	Walalawela, Niluksha, Vignoni, Mariana, Urrutia, María Noel, Belh, Sarah J., Greer, Edyta M., Thomas, Andrés Héctor, Greer, Alexander
Formato:	Articulo Preprint
Lenguaje:	Inglés
Publicado:	2018
Materias:	Química Solubility Alkylation Chemistry Two-dimensional nuclear magnetic resonance spectroscopy Pterin Tetrahydrofuran Yield (chemistry) Regioselectivity Photochemistry Triplet state
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/127363
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

id	I19-R120-10915-127363
record_format	dspace
institution	Universidad Nacional de La Plata
institution_str	I-19
repository_str	R-120
collection	SEDICI (UNLP)
language	Inglés
topic	Química Solubility Alkylation Chemistry Two-dimensional nuclear magnetic resonance spectroscopy Pterin Tetrahydrofuran Yield (chemistry) Regioselectivity Photochemistry Triplet state
spellingShingle	Química Solubility Alkylation Chemistry Two-dimensional nuclear magnetic resonance spectroscopy Pterin Tetrahydrofuran Yield (chemistry) Regioselectivity Photochemistry Triplet state Walalawela, Niluksha Vignoni, Mariana Urrutia, María Noel Belh, Sarah J. Greer, Edyta M. Thomas, Andrés Héctor Greer, Alexander Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
topic_facet	Química Solubility Alkylation Chemistry Two-dimensional nuclear magnetic resonance spectroscopy Pterin Tetrahydrofuran Yield (chemistry) Regioselectivity Photochemistry Triplet state
description	Alkylation patterns and excited-state properties of pterins were examined both experimentally and theoretically. 2D NMR spectroscopy was used to characterize the pterin derivatives, revealing undoubtedly that the decyl chains were coupled to either the O4 or N3 sites on the pterin. At a temperature of 70°C, the pterin alkylation regioselectively favored the O4 over the N3. The O4 was also favored when using solvents, in which the reactants had increased solubility, namely N,N-dimethylformamide and N,N-dimethylacetamide, rather than solvents in which the reactants had very low solubility (tetrahydrofuran and dichloromethane). Density functional theory (DFT) computed enthalpies correlate to regioselectivity being kinetically driven because the less stable O-isomer forms in higher yield than the more stable N-isomer. Once formed these compounds did not interconvert thermally or undergo a unimolecular "walk" rearrangement. Mechanistic rationale for the factors underlying the regioselective alkylation of pterins is suggested, where kinetic rather than thermodynamic factors are key in the higher yield of the O-isomer. Computations also predicted greater solubility and reduced triplet state energetics thereby improving the properties of the alkylated pterins as 1 O2 sensitizers. Insight on thermal and photostability of the alkylated pterins is also provided.
format	Articulo Preprint
author	Walalawela, Niluksha Vignoni, Mariana Urrutia, María Noel Belh, Sarah J. Greer, Edyta M. Thomas, Andrés Héctor Greer, Alexander
author_facet	Walalawela, Niluksha Vignoni, Mariana Urrutia, María Noel Belh, Sarah J. Greer, Edyta M. Thomas, Andrés Héctor Greer, Alexander
author_sort	Walalawela, Niluksha
title	Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
title_short	Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
title_full	Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
title_fullStr	Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
title_full_unstemmed	Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
title_sort	kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study
publishDate	2018
url	http://sedici.unlp.edu.ar/handle/10915/127363
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Kinetic control in the regioselective alkylation of pterin sensitizers: a synthetic, photochemical, and theoretical study

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