A49 Alkoxysilane groups for instant labelling of biomolecules with 18F

Choudhry, Uzma; Martin, Katherine; Biagini, Stefano C. G.; Blower, Philip J.

doi:10.1097/00006231-200603000-00060

Cited by 15 publications

(57 citation statements)

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“…Furthermore, Choudhry and Blower investigated the behavior of different sized alkyl groups (Me, Ph, tert -Bu) and their combinations connected to fluorosilanes. The results showed that tert- butyldiphenyl[ 18 F]fluorosilane ([ 18 F] 68 ) contained the highest stabilized Si-F-bond [122]. Contemporaneously, Schirrmacher and Jurkschat carried out comparable experiments and found di- tert- butylphenylfluorosilane ([ 18 F] 69 ) with the highest stability against hydrolysis of Si-F-bond and called this compound class SiFA (silicon-based fluoride-acceptor).…”

Section: Deuteration On Other Parts Of the Molecule To Avoid Degramentioning

confidence: 99%

“…Next, the introduction of fluorine-18 was evaluated by the use of different leaving groups such as alkoxycarbonyl-groups [122,133], by halogen and isotope exchange [118,123] and by applying hydrosilanes [134]. Manifold examples for the use of the SiFA concept were octreotide, bombesin, RGD, PSMA, antibodies, simple molecules, carbohydrates, and biotin.…”

Section: Deuteration On Other Parts Of the Molecule To Avoid Degramentioning

confidence: 99%

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Methods to Increase the Metabolic Stability of 18F-Radiotracers

2015

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Abstract:The majority of pharmaceuticals and other organic compounds incorporating radiotracers that are considered foreign to the body undergo metabolic changes in vivo. Metabolic degradation of these drugs is commonly caused by a system of enzymes of low substrate specificity requirement, which is present mainly in the liver, but drug metabolism may also take place in the kidneys or other organs. Thus, radiotracers and all other pharmaceuticals are faced with enormous challenges to maintain their stability in vivo highlighting the importance of their structure. Often in practice, such biologically active molecules exhibit these properties in vitro, but fail during in vivo studies due to obtaining an increased metabolism within minutes. Many pharmacologically and biologically interesting compounds never see application due to their lack of stability. One of the most important issues of radiotracers development based on fluorine-18 is the stability in vitro and in vivo. Sometimes, the metabolism of

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Section: Deuteration On Other Parts Of the Molecule To Avoid Degramentioning

confidence: 99%

Section: Deuteration On Other Parts Of the Molecule To Avoid Degramentioning

confidence: 99%

Methods to Increase the Metabolic Stability of 18F-Radiotracers

2015

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“…The authors also reported an early stability study of a series of labeled SiFA derivatives ( vide infra ). This result was reported almost simultaneously with the important contribution of Choudhry et al establishing a silicon-leaving group approach to the radiosynthesis of [ 18 F]SiFA starting from an alkoxy-substituted acceptor precursor [20]. The reaction proceeded directly from aqueous 18 F − and allowed for the efficient conversion of tert -butyldiphenylmethoxysilane ( 6 ) to [ 18 F] tert -butyldiphenylfluorosilane ([ 18 F] 7 ) at room temperature in 5 minutes.…”

Section: Sifa Labeling Chemistrymentioning

confidence: 73%

¹⁸F-Labeled Silicon-Based Fluoride Acceptors: Potential Opportunities for Novel Positron Emitting Radiopharmaceuticals

Bernard‐Gauthier

Wängler

Schirrmacher

et al. 2014

BioMed Research International

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Background. Over the recent years, radiopharmaceutical chemistry has experienced a wide variety of innovative pushes towards finding both novel and unconventional radiochemical methods to introduce fluorine-18 into radiotracers for positron emission tomography (PET). These “nonclassical” labeling methodologies based on silicon-, boron-, and aluminium-18F chemistry deviate from commonplace bonding of an [18F]fluorine atom (18F) to either an aliphatic or aromatic carbon atom. One method in particular, the silicon-fluoride-acceptor isotopic exchange (SiFA-IE) approach, invalidates a dogma in radiochemistry that has been widely accepted for many years: the inability to obtain radiopharmaceuticals of high specific activity (SA) via simple IE. Methodology. The most advantageous feature of IE labeling in general is that labeling precursor and labeled radiotracer are chemically identical, eliminating the need to separate the radiotracer from its precursor. SiFA-IE chemistry proceeds in dipolar aprotic solvents at room temperature and below, entirely avoiding the formation of radioactive side products during the IE. Scope of Review. A great plethora of different SiFA species have been reported in the literature ranging from small prosthetic groups and other compounds of low molecular weight to labeled peptides and most recently affibody molecules. Conclusions. The literature over the last years (from 2006 to 2014) shows unambiguously that SiFA-IE and other silicon-based fluoride acceptor strategies relying on 18F− leaving group substitutions have the potential to become a valuable addition to radiochemistry.

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“…They suggested the use of alkoxy silanes as potential precursor compounds for the 18 F-labeling with aqueous HF, actually a reaction already well known to organic chemists for the deprotection of silylated alcohols. The key to prevent fast hydrolysis is the introduction of sterically hindered substituents, a fact which was discovered and proven to be valid almost simultaneously by Blower and co-workers [27] and Schirrmacher and Jurkschat in 2006 [28]. Alkoxysilanes as well as hydroxylsilanes and chlorosilanes readily react with 18 F − in excellent to quantitative yields.…”

Section: F Radiochemistrymentioning

confidence: 99%