Biogenic catecholamines fluorescent conjugates: synthesis and photophysieal characterization

摘要

Biogenic catecholamines such as epinephrine (adrenaline), norepinephrine and dopamine control adrenergic systems in the CNS and are responsible for the awake/asleep cycle, mood swings and act peripherally to modulate blood pressure, among other functions. The catecholamine biosynthetic pathway involves the amino acids phenylalanine, tyrosine and 3,4-dihydroxyphenylalanine (DOPA), as well as the structure related tyramine [1]. As a result there is a pratical interest in the fluorescent derivatisation of such analytes to enhance the sensitivity of detection, in order to quantify and elucidate mechanisms of physiological action [2]. Bearing this in mind, as well as our current research interests that include the synthesis of new fluorescent conjugates of biologically relevant molecules and studies on -their photorelease [3], a fluorescent pyrene moiety was linked to the biogenic amines dopamine la norepinephrine lb and epinephrine 1c and their biosynthesis precursors, phenylalanine methyl ester Id, tyrosine methyl ester 1e, 3,4-dihydroxyphenylalanine (DOPA) methyl ester If and tyramine le, through an urethane bond at their amino group. The derivatisation was carried out by reaction with 1-hydroxymethylpyrene in the presence of N,N-carbonyldiimidazole (CDI) in DMF, at room temperature, in fair yields. The resulting fluorescent conjugates 2a-g were fully characterized by the usual spectroscopic techniques, including UV-vis and fluorescence spectroscopy.