title: Photorelease of amino acids from novel thioxobenzo[f]benzopyran ester conjugates.
abstract: Aiming at the enhancement of the performance of (9-methoxy-3-oxo-3H-benzo[f]benzopyran-1-yl) methyl ester as photocleavable protecting group for the carboxylic acid function at long-wavelengths, 9-methoxy-3-thioxo-3H-benzo[f]benzopyran-L-valine and L-phenylalanine model conjugates were prepared through a thionation reaction of the corresponding oxo-benzobenzopyrans. These thioxobenzobenzopyran derivatives were subjected to photocleavage reactions in the same conditions as the parent oxo-benzobenzopyrans at different wavelengths of irradiation, and photocleavage data were obtained. It was found that the exchange of the carbonyl by a thiocarbonyl group enhanced the performance of the heterocyclic protecting group at 419 nm by improving the photolysis rates, making it an appropriate group for practical applications at long wavelengths.
authors: Centro de Química, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
authors: Ana M
authors: AM
authors: Piloto
authors: Ana M S
authors: AM
authors: Soares
authors: Susana P G
authors: SP
authors: Costa
authors: M Sameiro T
authors: MS
authors: Gonçalves
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D003374:Coumarins / Q000138:chemical synthesis*; D004952:Esters / Q000737:chemistry*; D007202:Indicators and Reagents / Q000138:chemical synthesis*; D008027:Light; D015394:Molecular Structure; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D010782:Photolysis; D013057:Spectrum Analysis; D013438:Sulfhydryl Compounds; D014633:Valine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D002264:Carboxylic Acids; D003374:Coumarins; D004952:Esters; D007202:Indicators and Reagents; D013438:Sulfhydryl Compounds; D010649:Phenylalanine; D014633:Valine