2-[18F]Fluorophenylalanine: Synthesis by Nucleophilic 18F-Fluorination and Preliminary Biological Evaluation

Synthesis ◽  
2019 ◽  
Vol 51 (03) ◽  
pp. 664-676 ◽  
Author(s):  
Bernd Neumaier ◽  
Daniel Modemann ◽  
Boris Zlatopolskiy ◽  
Elizaveta Urusova ◽  
Johannes Zischler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Biological Evaluation ◽  
Schiff Base Complexes ◽  
Biological Study ◽  
Automated Synthesis ◽  
Pet Tracer ◽  
Iodonium Salt ◽  
Acidic Conditions

2-[18F]Fluorophenylalanine (2-[18F]FPhe), a promising PET tracer for imaging of cerebral infarction and tumors, was efficiently prepared from an easily accessible iodonium salt precursor using Cu-mediated radiofluorination under ‘low base’ or ‘minimalist’ conditions. Whereas significant racemization was initially observed if the ‘minimalist’ protocol was applied for radiolabeling, it was completely suppressed by the careful adjustment of 18F– preprocessing. The initial biological study revealed a higher uptake of 2-[18F]FPhe in different tumor cells in comparison to that of [18F]FET. In contrast to 4-[18F]FPhe, which suffered from rapid defluorination in vivo, 2-[18F]FPhe demonstrated a sufficient in vivo stability. Conclusively, 2-[18F]FPhe is a promising PET probe that is now readily available using Cu-mediated radiofluorination under ‘minimalist’ or ‘low base’ conditions. The simplicity of the translation of the proposed procedures to automated synthesis modules allows a broad biological evaluation of 2-[18F]FPhe. Notably, a novel protocol for the preparation of N-Boc protected amino acids from the respective Ni-Schiff base complexes was developed that avoided application of strongly acidic conditions.

General method for the asymmetric synthesis of α-amino acids via alkylation of the chiral nickel(II) Schiff base complexes of glycine and alanine

1988 ◽  
pp. 305-312 ◽  
Author(s):  
Yuri. N. Belokon ◽  
Vladimir I. Bakhmutov ◽  
Nina I. Chernoglazova ◽  
Konstantin A. Kochetkov ◽  
Sergei V. Vitt ◽  
...  
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Asymmetric Synthesis ◽  
Schiff Base Complexes ◽  
General Method

scholarly journals Synthesis and Biological Evaluation of O-[3-18F-fluoropropyl]-α-methyl Tyrosine in Mesothelioma-Bearing Rodents

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
I-Hong Shih ◽  
Fan-Lin Kong ◽  
Mohammad S. Ali ◽  
Yinhan Zhang ◽  
Dong-Fang Yu ◽  
...  
Keyword(s):  
Radiochemical Purity ◽  
Biological Evaluation ◽  
Synthesis Methods ◽  
Automated Synthesis ◽  
Imaging Studies ◽  
Biodistribution Studies ◽  
Synthesis And Biological Evaluation ◽  
Automated Methods

Radiolabeled tyrosine analogs enter cancer cells via upregulated amino acid transporter system and have been shown to be superior to18F-fluoro-2-deoxy-D-glucose (18F-FDG) in differential diagnosis in cancers. In this study, we synthesized O-[3-19F-fluoropropyl]-α-methyl tyrosine (19F-FPAMT) and used manual and automated methods to synthesize O-[3-18F-fluoropropyl]-α-methyl tyrosine (18F-FPAMT) in three steps: nucleophilic substitution, deprotection of butoxycarbonyl, and deesterification. Manual and automated synthesis methods produced18F-FPAMT with a radiochemical purity >96%. The decay-corrected yield of18F-FPAMT by manual synthesis was 34% at end-of-synthesis (88 min). The decay-corrected yield of18F-FPAMT by automated synthesis was 15% at end-of-synthesis (110 min).18F-FDG and18F-FPAMT were used forin vitroandin vivostudies to evaluate the feasibility of18F-FPAMT for imaging rat mesothelioma (IL-45).In vitrostudies comparing18F-FPAMT with18F-FDG revealed that18F-FDG had higher uptake than that of18F-FPAMT, and the uptake ratio of18F-FPAMT reached the plateau after being incubated for 60 min. Biodistribution studies revealed that the accumulation of18F-FPAMT in the heart, lungs, thyroid, spleen, and brain was significantly lower than that of18F-FDG. There was poor bone uptake in18F-FPAMT for up to 3 hrs suggesting itsin vivostability. The imaging studies showed good visualization of tumors with18F-FPAMT. Together, these results suggest that18F-FPAMT can be successfully synthesized and has great potential in mesothelioma imaging.

scholarly journals Synthesis, Spectroscopic, Molecular Structure, and Antibacterial Studies of Dibutyltin(IV) Schiff Base Complexes Derived from Phenylalanine, Isoleucine, and Glycine

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Har Lal Singh ◽  
Jangbhadur Singh
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Schiff Bases ◽  
Molar Conductance ◽  
Schiff Base Complexes ◽  
Spectral Studies ◽  
E Coli ◽  
Elemental Analyses ◽  
In Vitro Antibacterial Activity

New series of organotin(IV) complexes and Schiff bases derived from amino acids have been designed and synthesized from condensation of1H-indole-2,3-dione, 5-chloro-1H-indole-2,3-dione, andα-amino acids (phenylalanine, isoleucine, and glycine). All compounds are characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (1H,13C, and119Sn NMR) spectral studies. The results suggest that Schiff bases behave as monobasic bidentate ligands and coordinate with dibutyltin(IV) in octahedral geometry according to the general formula [Bu2Sn(L)2]. Elemental analyses and NMR spectral data of the ligands with their dibutyltin(IV) complexes agree with their proposed distorted octahedral structures. Few representative compounds are tested for their in vitro antibacterial activity against Gram-positive (B. cereus,Staphylococcusspp.) and Gram-negative (E. coli,Klebsiellaspp.) bacteria. The results show that the dibutyltin complexes are more reactive with respect to their corresponding Schiff base ligands.

Preparation and characterisation of new oxovanadium(IV) Schiff base complexes derived from amino acids and aromatic o-hydroxyaldehydes

1999 ◽  
Vol 293 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J.Costa Pessoa ◽  
I. Cavaco ◽  
I. Correia ◽  
M.T. Duarte ◽  
R.D. Gillard ◽  
...  
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Schiff Base Complexes

scholarly journals Non-toxic Cobalt(III) Schiff Base Complexes with Broad Spectrum Antifungal Activity

2020 ◽  
Author(s):  
Angelo Frei ◽  
A. Paden King ◽  
Gabrielle J. Lowe ◽  
Amy K. Cain ◽  
Francesca L. Short ◽  
...  
Keyword(s):  
Schiff Base ◽  
Antifungal Activity ◽  
Broad Spectrum ◽  
Bacterial Infections ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
New Drugs ◽  
Schiff Base Complexes ◽  
In Vivo Studies

Resistance to currently available antifungal drugs has quietly been on the rise but overshadowed by the alarming spread of antibacterial resistance. There is a striking lack of attention to the threat of drug resistant fungal infections, with only a handful of new drugs currently in development. Given that metal complexes have proven to be useful new chemotypes in the fight against diseases such as cancer, malaria, and bacterial infections, it stands to reason to explore their possible utility in treating fungal infections. Herein we report a series of cobalt(III) Schiff base complexes with broad spectrum antifungal activity. Some of these complexes (1-3) show minimum inhibitory concentrations (MIC) in the low micro- to nanomolar range against a series of Candida and Cryptococcus yeasts. Additionally, we demonstrate that these compounds show no cytotoxicity against both bacterial and human cells. Finally, we report first in vivo toxicity data on these compounds in Galleria mellonella, showing that doses as high as 266 mg/kg are tolerated without adverse effects, paving the way for further in vivo studies of these complexes. <br>

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