Phenylethylamine sensor

Figure 5.24 — Enantioselective fluorimetric flow-through optrode using a lipophilic tartrate (di-/er/-butyrotartrate) as ion-carrier for the determination of (protonated) 1 -phenylethylamine. (A) Sensor response to increasing concentrations of the analyte [(—) S enantiomer (- - -) R enantiomer]. (B) Stem-Volmer calibration plot. and F denote fluorescence intensities = 520, = 600...

Substantial efforts have been devoted to the development of molecular sensors for dopamine. Raymo et al.70 reported a two-step procedure to coat silica particles with fluorescent 2,7-diazapyrenium dications sensing toward dopamine. The analysis of the fluorescence decay with multiple-equilibria binding model revealed that the electron deficient dications and the electron-rich analytes form 1 1 and 1 2 complexes at the particle/water interface. The interfacial dissociation constants of the 1 1 complexes were 5.6mM and 3.6mM for dopamine and catechol, respectively. Dopamine was dominated by the interaction of its electron-rich dioxyarene fragment with the electron-deficient fluorophore in neutral aqueous environments. Ahn et al.71 reported tripodal oxazoline-based artificial receptors, capable of providing a preorganized hydrophobic environment by rational design, which mimics a hydrophobic pocket predicted for a human D2 receptor. A moderate binding affinity, a dissociation constant of 8.2 mM was obtained by NMR titrations of tripodal oxazoline-based artificial receptor with dopamine in a phosphate buffer solution (pH 7.0). Structurally related ammonium ions, norepinephrine, 2-phenylethylamine,... 

Tripodal cleft-Uke molecules such as 40 were shown to act as fluorescence sensors for ammonium ions starting from this model bis(oxazolinyl)phenols (41) were developed and were shown to undergo conformational changes, due to the interaction with amine guests, leading in some cases to fluorescence enhancement and in others to fluorescence sensing. Enantioselective fluorescence sensing of phenylethylamine was observed. The steric interactions between the oxazolinyl... 

Upadhyay SP, Pissurlenkar RRS, Coutinho EC et al (2007) Furo-fused BINOL based crown as a fluorescent chiral sensor for enantioselective recognition of phenylethylamine and ethyl ester of valine. J Org Chem 72 5709-5714... 

Protocol 1 The reaction was performed in a CEM Discover 1-300 W system equipped with a built-in pressure measurement sensor and a vertically focused IR temperature measurement sensor using the mode Discover Standard. A solution of 5,5-dimethyl-2-diazocyclohexan-1,3-dione (1, 115 mg, 0.69 mmol), benzaldehyde (70 pL, 0.69 mmol), and fR)-phenylethylamine (88 p,L, 0.69 mmol) in 2mL of anhydrous toluene (0.35 M) under an argon atmosphere in a 10-mL sealed borosilicate tubular reaction vessel containing a Teflon-coated magnetic stirring bar was irradiated at 140 °C for 5 minutes after a ramp-up time of 2 minutes (total irradiation time = 7 minutes). The resulting reaction mixture was cooled to 50 °C by air flow, concentrated, and directly purified by flash chromatography on silica gel eluted with EtOAc/petrol ether to afford the... 

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