Biphasic Enantioselective Fluorescent Recognition of Amino Acids by a Fluorophilic Probe

Abstract

Af luorophilic fluorescent probe based on ap erfluoroalkyl-substituted bis(binaphthyl) compound wasd esigned and synthesized.I td isplayed ah ighly enantioselective fluorescencer esponse towards tructurally diverse amino acids in ab iphasic fluorous/aqueous system with enantiomeric fluorescent enhancementr atio (ef; DI D /DI L )v alues up to 45.2 (histidine). It can be used to determinet he enantiomeric compositions of amino acids and also allows the amino acid enantiomerst ob ev isually discriminated. NMR and mass-spectroscopic investigations provided insights into the observedh igh enantioselectivity.T his biphasic fluorescent recognition was used to determine the enantiomeric composition of the crude phenylalanine products generated by an enzyme-catalyzed asymmetrichydrolysis under various reactionc onditions. The fluorous-phase-based fluorescence measurement under the biphasic conditions wasa ble to minimize the interference of other reaction componentsa nd thus has potential in asymmetricreactionscreening.[a] Dr.Y .-Y.Zhu SchoolofC hemistry and EnvironmentalE ngineering Wuhan Institute of Technology, Wuhan4 30205 (P.R.C hina)[b] Dr.

Enantioselective Fluorescent Recognition of Free Amino Acids: Challenges and Opportunities

“…In the screening of chemical reactions for the asymmetric synthesis of chiral amino acids,t he addition of af luorescent probe to acomplex reaction mixture to directly determine the yield and enantiomeric composition of the amino acid products without separation may suffer from possible interferences from the diverse reaction components,including the starting materials,reagents,metal catalysts,various additives, and side products.Afew strategies to minimize these interferences have been proposed:1 )The fluorophilic probe (R,R)-22 was used to selectively extract an amino acid from its aqueous solution into af luorous phase for fluorescence measurement. [29] 2) Thea mphiphilic polymer-supported probe (S)-18 was used to transport an amino acid away from its original solution (aqueous or organic) for fluorescence measurement. [25] 3) TheL CST property of polymer (S)-18 also made it possible to separate the amino acid/probe adduct from the original substrate solution by varying the temperature.…”

“…Zhu et al. have introduced a perfluoroalkyl chain to the bisBINOL‐based aldehyde to make the highly fluorinated probe ( R , R )‐ 22 [29] …”

“…[28] Zhu et al have introduced aperfluoroalkyl chain to the bisBINOL-based aldehyde to make the highly fluorinated probe (R,R)-22. [29] This compound was soluble in the fluorous solvent 1H,1H,2H,2H-perfluoro-1-octanol (PFOH). When as olution of (R,R)-22 (4.0 10 À5 m,2 .0 mL) in PFOH was mixed with an aqueous solution (2.0 mL) of amino acids and Zn II (1.0 equiv) in the presence of TBAOH, the fluorescence of the fluorous phase in the biphasic system showed ag ood enantioselective enhancement.…”

Accelerated Asymmetric Reaction Screening with Optical Assays

“…13 In 2019, Pu and colleagues used the bis(binaphthyl)based fluorescent probe 23 to evaluate the effect of solvent variation on the enantioselectivity of the enzymatic hydrolysis of phenylalanine methyl ester (24) (Scheme 5). 14 The probe has a highly fluorinated alkyl chain and can be used in a biphasic aqueous/1H,1H,2H,2H-perfluoro-1-octanol (PFOH) system. Upon completion of the reaction, the free amino acid 25 is extracted into the fluorous phase where enantioselective fluorescent detection takes place, probably through the formation of zinc(II) complex 26.…”

Natural Occurrence, Biological Functions, and Analysis of D-Amino Acids

“…[102][103][104][105][106][107] Enantioselective fluorescent probes for chiral recognition of protected and free amino acids have sprung up like mushrooms in recent years. [108][109][110][111][112][113][114] These chiral fluorescent probes have great potential for analysis of the optical purity and concentrations of amino acids, as well as high-throughput screening of asymmetric reactions for preparing chiral amino acids.…”