A photochemical and theoretical study of the triplet reactivity of furano- and pyrano-1,4-naphthoquionones towards tyrosine and tryptophan derivatives.

ABSTRACT: The photochemical reactivity of the triplet state of pyrano- and furano-1,4-naphthoquinone derivatives (1 and 2) has been examined employing nanosecond laser flash photolysis. The quinone triplets were efficiently quenched by l-tryptophan methyl ester hydrochloride, l-tyrosine methyl ester hydrochloride, N-acetyl-l-tryptophan methyl ester and N-acetyl-l-tyrosine methyl ester, substituted phenols and indole (k _q ∼10⁹ L mol^-1 s^-1). For all these quenchers new transients were formed in the quenching process. These were assigned to the corresponding radical pairs that resulted from a coupled electron/proton transfer from the phenols, indole, amino acids, or their esters, to the excited state of the quinone. The proton coupled ele

SUBMITTER: Teixeira RI 

PROVIDER: S-EPMC9063979 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature