Current Organic Chemistry - Volume 17, Issue 19, 2013

This paper revisits some aspects of carbon-11 radiochemistry from the production of the primary labeling reagents and fast chemical transformations used to convert them into more useful building blocks such as [11C]methyl iodide and [11C]carbon monoxide. The application facet covers traditional methylation, carboxylation and other reactions in the preparation of PET tracers. Technical aspects and strategie Read More

This review article summarizes the recent information regarding general aspects in the automated synthesis of 18F-labelled PET radiotracers that are prepared via nucleophilic fluorination pathway. The previous and on-going researches in development of different automation solutions are discussed and the current trends in large scale production of radiotracers are considered. The advantages and limitations of the fully au Read More

Sharpless et al. presented, in 2001, a review in which they introduced the concept of “click chemistry”. In this review a “new way” of making chemicals, with a particular emphasis on drugs, is presented. Current drugs are often based on natural products that were first extracted from plants or other organisms and then with enormous effort were synthetically reproduced by chemists. Sharpless et al. propose to shift th Read More

[11C]methyl iodide was originally produced by using LiAlH4 to reduce [11C]CO2 to [11C]methanol, followed by reaction with liquid hydriodic acid. However, it is difficult to obtain the desired high specific radioactivity of the end-product 11C-methylated tracer because the lithium reagent solution is so easily contaminated by atmospheric [11C]CO2 The introduction of high temperature gas-phase methodologies greatly enh Read More

For PET applications in oncological and neurological diagnostics, amino acids have been studied both clinically and pre-clinically during the last 35 years. Nowadays two applications of labelled amino acids for visualisation of tumours attract the main attention: [11C] or [18F]amino acids as substrates of specific membrane transport systems or in vivo measurement of protein synthesis rate. In this review we focussed on 11C Read More

Organic chemistry with short-lived positron emitters has evolved into a complex chemical science. Special efforts are focused on the development of rapid, selective and functional group-tolerating reactions with the most prominent short-lived positron emitter fluorine-18 (18F, 1/2= 109.8 min). The use of catalysts such as palladium complexes represents a highly promising approach for rapid and efficient syntheses of a wide var Read More

The automation of quality control methods used for release of [18F]fluoride-labeled radiotracers is a logical next step for increasing reliability and decreasing exposure in day-to-day clinical manufacture. In this work we evaluate the suitability for automation in six key release tests: Radiochemical purity and identity, determination of pH, kryptofix and residual solvents, as well as filter membrane integrity test. Results Read More

Due to favourable in-vivo characteristics, the long half-life of 18F (110 min) allowing for remote-site delivery and its high specificity, O-(2’-[18F]fluoroethyl)-L-tyrosine ([18F]FET) has gained increased importance for molecular imaging of cerebral tumors. Consequently, the development of simple and efficient production strategies for FET could be an important step to further improve the cost-effective availability of FET i Read More

Among the contingency of methodologies available for bioconjugation, the Click dipolar [3+2] cycloaddition pathway that results in the formation of triazole linkage were extensively investigated during the last few years in a wide variety of molecular architectures – that ranges between small molecules and polymers. Synthetic feasibility as well as the stability and application of triazole linkage were explored and successfully ac Read More

Among the broad range of transition metal-catalyzed reactions, the Heck reaction is an attractive methodology frequently being used for the synthesis of natural and biologically active products, since a palladium-catalyzed reaction of this kind can directly create complex molecules under mild conditions from readily available starting materials. This feature article provides the comprehensive summary of currently available Read More