Microfluidic radiosynthesis of [¹⁸F]FEMPT, a high affinity PET radiotracer for imaging serotonin receptors

• Thomas Lee Collier,
• Steven H. Liang,
• J. John Mann,
• Neil Vasdev and
• J. S. Dileep Kumar

Beilstein J. Org. Chem. 2017, 13, 2922–2927, doi:10.3762/bjoc.13.285

• -18; 5-HT1A; microfluidics; PET; Introduction The development of serotonin 1A receptor (5-HT1AR) agonist radiotracers for applications in molecular imaging with positron emission tomography (PET) has been avidly sought over the past two decades, albeit with limited success. The current status of

• serotonin-targeting radiopharmaceuticals was recently reviewed by Paterson et al. [1] and their conclusion was that “the development of PET and single-photon emission computed tomography (SPECT) radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to

• invaluable insight into normal and abnormal brain function”. A further review by us focusing on 5-HT1AR overviewed a number of PET and SPECT tracers that have been tested in vivo with varying efficacy [2]. A few representative compounds which show the structures that have been tested as radiotracers are

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

• Irwan Iskandar Roslan,
• Kian-Hong Ng,
• Gaik-Khuan Chuah and
• Stephan Jaenicke

Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270

• antimicrobial [35][36], antitumor [37][38][39], antibacterial [40], and anti-allergic agents [41]. In addition, compounds with this backbone are employed as kinase inhibitors and receptors [42][43][44] and as a tracer for PET imaging of β-amyloid plaques [45][46]. The conventional approach for the construction

Regioselective decarboxylative addition of malonic acid and its mono(thio)esters to 4-trifluoromethylpyrimidin-2(1H)-ones

• Sergii V. Melnykov,
• Andrii S. Pataman,
• Yurii V. Dmytriv,
• Svitlana V. Shishkina,
• Mykhailo V. Vovk and
• Volodymyr A. Sukach

Beilstein J. Org. Chem. 2017, 13, 2617–2625, doi:10.3762/bjoc.13.259

• Organofluorine compounds now play an essential role in the development of new materials for solar cells [1][2][3], radiotracers for PET imaging [4], agrochemicals [5][6], sensitive chemical probes for 19F nuclear magnetic resonance investigation of biological experiments [7][8], and are most widely used in the

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• radical intermediate 46 governs the formal [4 + 2]-cycloaddition reaction of E-1b with 3,4-di(α-styryl)furan (47, Scheme 15). The photoinduced reaction occurs via an electron-transfer (PET) process and led to the formation of the polycyclic product 48 in a stereospecific manner [52]. Similar products were

Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz–Fritsch–Bobbitt reaction with non-activated and moderately-activated systems

• Marco Mottinelli,
• Mathew P. Leese and
• Barry V. L. Potter

Beilstein J. Org. Chem. 2017, 13, 1871–1878, doi:10.3762/bjoc.13.182

• a Bruker microTOF. Melting points were determined using an Optimelt block and are uncorrected. 2,2-Dimethoxyacetaldehyde was purchased as an aqueous solution and was extracted in CHCl3 before use. Petroleum ether (pet. ether) used for chromatography was the 40–60 °C distillate. The general

• yellow oil (3.87 g). N-Benzyl-N-(2,2-dimethoxyethyl)aniline (9a). The crude compound was purified by column chromatography (eluent: from 0–30% EtOAc in pet. ether) to give 9a as a colorless oil (2.92 g, 99%) which showed: 1H NMR (500 MHz, CDCl3) δ 3.41 (s, 6H, OCH3), 3.58 (d, J = 5.1 Hz, 2H, NCH2CH

• according to method A. A sample of the crude compound was purified by column chromatography (eluent: from 0% to 10% EtOAc in pet. ether) to give a yellow oil which showed: 1H NMR (500 MHz, CDCl3) δ 2.65 (bs, 1H, OH), 3.39 (dd, J = 2.6, 12.6 Hz, 1H, H3-THIQ), 3.86 (ddd, J = 1.1, 3.8, 12.6 Hz, 1H, H3-THIQ

Direct catalytic arylation of heteroarenes with meso-bromophenyl-substituted porphyrins

• Alexei N. Kiselev,
• Olga K. Grigorova,
• Alexei D. Averin,
• Sergei A. Syrbu,
• Oskar I. Koifman and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2017, 13, 1524–1532, doi:10.3762/bjoc.13.152

• application of such medicaments are antitumor remedies and non-invasive diagnostic imaging agents for PET, SPECT and MRI methods [5]. The combination of porphyrin and heterocyclic moieties in one molecule is perspective for the design of new compounds with potential powerful pharmaceutical properties. Up to

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• brain. AuNPs were decorated in a controlled ratio with glucose, neuropeptides and a chelator of gallium-68, a sensitive positron emission tomography (PET) tracer, affording the quantification of BBB permeability in healthy small animals. Glyco-gold nanoparticles in immunology The development of

Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials

• Atsushi Tamura,
• Asato Tonegawa,
• Yoshinori Arisaka and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287

• ) contrast agents and positron emission tomography (PET) probes for in vivo studies. Conclusion In this study, we described a novel preparation method for end-reactive PRXs using 3 as an axle polymer for the PRXs. The terminal 2-amino-3-phenylpropyl groups of 3 prevent the dethreading of α-CDs after end

Biochemical and structural characterisation of the second oxidative crosslinking step during the biosynthesis of the glycopeptide antibiotic A47934

• Veronika Ulrich,
• Clara Brieke and
• Max J. Cryle

Beilstein J. Org. Chem. 2016, 12, 2849–2864, doi:10.3762/bjoc.12.284

• . StaF was expressed with an N-terminal hexahistidine-tag and under the control of the T7 promoter. The StaH construct (pET28a StaH) as well as all NRPS constructs (pET MBP-PCPsta-Xsta 1c, pET MBP-PCPtei-Xtei 1c, pET MBP-PCPtei-Xsta 1c, pET MBP-PCPsta-Xtei 1c, pET NCL-4 MBP-Xsta) were employed from a

Synthesis, dynamic NMR characterization and XRD studies of novel N,N’-substituted piperazines for bioorthogonal labeling

• Constantin Mamat,
• Marc Pretze,
• Matthew Gott and
• Martin Köckerling

Beilstein J. Org. Chem. 2016, 12, 2478–2489, doi:10.3762/bjoc.12.242

• bioorthogonal 18F-containing building blocks The development of new 18F-based radiotracers remains an ongoing goal in the field of radiopharmacy and provides tools for specific cancer diagnostics using positron emission tomography (PET) [31][32][33]. When radiotracers are based on tumor-specific peptides

• radioactive peaks on a radio-TLC using a radio-TLC scanner (Fuji, BAS2000). [18F]Fluoride was produced using the PET cyclotron Cyclone 18/9 (IBA). [18O]H2O was irradiated with protons (18 MeV, 30 µA) exploiting the 18O(p,n)18F nuclear reaction. CAUTION! Hazard warning for organic azides: risk of explosion by

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• as supplied, and dried before use if required with appropriate drying agents or using an Innovative Technologies Inc. Solvent Purification System. Thin-layer chromatography (TLC) was conducted using Merck Millipore silica gel 60G F254 25 glassplates and/or TLC-PET foils of aluminium oxide with

Self and directed assembly: people and molecules

• Tony D. James

Beilstein J. Org. Chem. 2016, 12, 391–405, doi:10.3762/bjoc.12.42

• fluorescent photoinduced electron transfer (PET) pH sensors developed by A. P. De Silva (Figure 3) [17] in order to develop a fluorescence sensor for saccharides [18]. Thus creating a system where the neighbouring nitrogen lowered the working pH of the boronic acid and provided a fluorescence signalling

• collaborate and in particular we worked together to improve the chiral discriminating systems. In order to improve the chiral systems we designed sensors using a d-PET rather than the normal a-PET fluorescence sensing mechanism. With d-PET systems the fluorophore is the electron donor and the protonated amine

• /boronic acid moiety as the acceptor (the reverse is true for normal a-PET systems). Therefore, d-PET systems have a significant advantage over the a-PET systems at acidic pH, since background emission for these sensors is much lower. This is particularly important given that we were developing receptors

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

• Eric V. Anslyn

Beilstein J. Org. Chem. 2016, 12, 362–376, doi:10.3762/bjoc.12.40

• soda indeed sparked the idea of pursuing a citrate sensor, the idea of working on sensing had been percolating in my mind for a while. A. P. De Silva was pioneering the use of PET (photoinduced electron transfer) signaling [71], Seiji Shinkai (and his post-doctoral associate Tony James) were creating

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

• Charlotte Collet,
• Françoise Chrétien,
• Yves Chapleur and
• Sandrine Lamandé-Langle

Beilstein J. Org. Chem. 2016, 12, 353–361, doi:10.3762/bjoc.12.39

• derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments. Keywords: C-branched; diastereoselective; fluoroinositols; inositols; O-alkylated

• the corresponding fluoroinositol (1-fluoro-1-deoxy-scyllo-inositol) was also a good candidate to limit this aggregation. However, in vivo studies in animal models of Alzheimer disease with 1-[18F]fluoro-1-deoxy-scyllo-inositol used as radiotracer for positron emission tomography (PET) have shown that

• this compound crosses the blood brain barrier (BBB) with difficulty [32]. The same PET imaging studies using the diastereoisomeric compound of myo configuration (2-[18F]fluoro-2-deoxy-myo-inositol), did not get better results [33]. On the other hand, these radiotracers have shown interesting features

Bright molecules for sensing, computing and imaging: a tale of two once-troubled cities

• A. Prasanna de Silva

Beilstein J. Org. Chem. 2015, 11, 2774–2784, doi:10.3762/bjoc.11.298

• A. Prasanna de Silva School of Chemistry and Chemical Engineering, Queen's University, Belfast BT9 5AG, Northern Ireland 10.3762/bjoc.11.298 Abstract The circumstances in Colombo, Sri Lanka, and in Belfast, Northern Ireland, which led to a) the generalization of luminescent PET (photoinduced

• identification, nanometric mapping, animal visual perception and visual art are also outlined. Keywords: blood electrolyte analyzer; luminescent PET sensing/switching; molecular logic-based computation; photoinduced electron transfer; small molecular edge detection; Review Prologue Colombo, Sri Lanka: A civil

• from this ferment was photoinduced electron transfer (PET) [6][7], especially following the previous realization of its central role in green plant photosynthesis. It appealed to the physicochemical side of me that PET allows one to think primarily in terms of redox potentials, while atomic details

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• trifluoromethylation of aryl iodides with ClCF2CO2Me and fluoride can be utilized for clinical studies. Herein, we introduce one example of decarboxylative [18F]trifluoromethylation for positron emission tomography (PET) studies. A synthetic methodology for [18F]labelled-CF3 arenes is desired for the application of

• PET imaging. The reason is that the [18F] isotope has a longer half-life (110 min) than 13N (10 min) or 15O (2 min); however, the incorporation of [18F] must be rapid and the use of the products containing [18F] must be immediate. Many of the reported strategies have a limited scope of starting

• materials or require expensive reagents and a multistep synthesis. The [18F]trifluoromethylation performed with commercially available reagents by using [18F]fluoride demands no complex such as [18F]CF2Cu, and thus the method should contribute to efficient PET imaging [42] (Scheme 8). Synthesis of

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

• Nicolas Desbois,
• Sandrine Pacquelet,
• Adrien Dubois,
• Clément Michelin and
• Claude P. Gros

Beilstein J. Org. Chem. 2015, 11, 2202–2208, doi:10.3762/bjoc.11.239

• easily prepared as potential MRI/PET (SPECT) bimodal contrast agents incorporating one metal (Mn, Gd) for the enhancement of contrast for MRI applications and one “cold” metal (Cu, Ga, In) for future radionuclear imaging applications. Preliminary relaxivity measurements showed that the reported complexes

• are promising contrast agents (CA) in MRI. Keywords: click chemistry; corrole; DOTA; microwave; NOTA; porphyrin; Introduction Magnetic resonance imaging (MRI), positron emission tomography (PET) or single photon emission computed tomography (SPECT) are actually the most commonly used imaging

• modalities. MRI provides high-resolution (at the submillimeter level), but is limited by its low sensitivity. Conversely, PET and SPECT imaging are more sensitive methods but they both suffer from low anatomical resolution. As one single modality is usually not sufficient to obtain all the necessary

Preparation of conjugated dienoates with Bestmann ylide: Towards the synthesis of zampanolide and dactylolide using a facile linchpin approach

• Jingjing Wang,
• Samuel Z. Y. Ting and
• Joanne E. Harvey

Beilstein J. Org. Chem. 2015, 11, 1815–1822, doi:10.3762/bjoc.11.197

• by silica column chromatography. (2′E,2E,4E)-Hex-2′-enyl 5-phenylpenta-2,4-dienoate (11a). Rf = 0.23 (20:1 pet. ether:Et2O); 1H NMR (500 MHz, CDCl3) δ 7.48–7.43 (complex m, 3H), 7.36 (app. t, J = 7.6 Hz, 2H), 7.30 (t, J = 6.9 Hz, 1H), 6.93–6.82 (complex m, 2H), 6.01 (d, J = 15.6 Hz, 1H), 5.81 (dt, J

• (neat) cm−1: 2958 (m), 2929 (m), 1706 (s), 1625 (s), 1449 (m), 1236 (s), 1172 (s), 997 (m), 689 (m); HRMS (ESI) m/z: [M + H]+ calcd for C17H21O2, 257.1536 found, 257.1529, (Δ = 2.7 ppm). (1′R,2′S,5′R,2E,4E,6E)-2′-Isopropyl-5′-methylcyclohex-1′-yl deca-2,4,6-trienoate (11f). Rf = 0.14 (40:1 pet

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• ] cycloaddition reaction [36] (Scheme 15) offered a highly efficient method with excellent regioselectivity (in case of bulky groups), with additional advantage of the C-6 fluorinated methyl substituent – promising for PET probe development. Most of the metal catalysts employed for phenanthridine synthesis are

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• packed in a brown bottle or carton [144]. Mestdagh et al. [145] performed a comparative study of RF photodegradation in milk by using four different types of polyethylene terephthalate (PET) packages. Their results indicated that the packages provided with additional light protection and triple white

Homogeneous and heterogeneous photoredox-catalyzed hydroxymethylation of ketones and keto esters: catalyst screening, chemoselectivity and dilution effects

• Axel G. Griesbeck and
• Melissa Reckenthäler

Beilstein J. Org. Chem. 2014, 10, 1143–1150, doi:10.3762/bjoc.10.114

• appear in Table 2 for a series of ketone substrates. In order to explore the catalyst profile we tested other reaction conditions for the TiO2 catalysis, other metal-containing heterogeneous and homogeneous catalysts as well as the classical organic PET catalyst 9,10-dicyanoanthracene (DCA). The results

Organic synthesis using photoredox catalysis

• Axel G. Griesbeck

Beilstein J. Org. Chem. 2014, 10, 1097–1098, doi:10.3762/bjoc.10.107

• synthesis, the principles of photoredox chemistry serve as guidelines, i.e., photoinduced electron transfer (PET) kinetics and thermodynamics as expressed in the Rehm–Weller and Marcus equations. For catalytic versions, the photoinduced redox processes require efficient and robust photocatalysts, and in

The Ugi four-component reaction as a concise modular synthetic tool for photo-induced electron transfer donor-anthraquinone dyads

• Sarah Bay,
• Gamall Makhloufi,
• Christoph Janiak and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 1006–1016, doi:10.3762/bjoc.10.100

• ]. This photo-induced electron transfer (PET) [30][31][32][33][34] has been investigated with donors such as porphyrines, polycyclic aromatic hydrocarbons, perylenediimides and (oligo)thiophenes [35][36], tetrathiafulvalenes [37], as well as phenothiazine and its derivatives [22][38][39][40]. The latter

• have become attractive electrophores due to their reversible and tunable oxidation potential. Interestingly quenching of the phenothiazine inherent fluorescence offers a facile evidence for the occurrence of intramolecular PET in phenothiazine-containing Do–Acc dyads [41][42]. As suitable acceptor

• Equation 2, and upon taking solvation into account with the term . Therefore, the extent of the thermodynamically favored charge separation by an intramolecular photo-induced electron transfer (PET), plausibly explaining the observed fluorescence quenching, can be easily determined and compared within the

Visible-light-induced, Ir-catalyzed reactions of N-methyl-N-((trimethylsilyl)methyl)aniline with cyclic α,β-unsaturated carbonyl compounds

• Dominik Lenhart and
• Thorsten Bach

Beilstein J. Org. Chem. 2014, 10, 890–896, doi:10.3762/bjoc.10.86

• ; Introduction The photoinduced electron transfer (PET) of an amine to an excited oxidant followed by the loss of a cationic leaving group allows accessing a broad variety of α-aminoalkyl radicals [1][2][3][4]. As first shown by Mariano et al. [5][6] and by Pandey et al. [7] a trimethylsilyl (TMS) group is a

• enones were made by Hoffmann et al., who established the use of aromatic ketones as suitable PET catalysts for these reactions [31][32][33][34][35][36][37]. In Scheme 1, the addition reaction of N,N-dimethylaniline (1) to (5R)-menthyloxyfuran-2(5H)-one (2) is shown, which proceeds to the intriguing

• as a co-solvent [39] and that the diastereoselectivity depends both on the stereogenic center at C5 and on the chirality of the menthyl (Men) backbone [40]. In more recent work [41][42], Nishibayashi et al. showed that iridium complexes can serve as efficient PET catalysts for the addition of α

Flow microreactor synthesis in organo-fluorine chemistry

• Hideki Amii,
• Aiichiro Nagaki and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314

• , [18F]FDG is radiopharmaceutically used for positron emission tomography (PET). However, due to the short radioactivity elimination half-life of [18F] (t1/2 = 110 min), protocols for rapid and selective synthesis of [18F]-labeled compounds have been required. In addition, on-site and on-demand chemical

• production of PET agents with automation and ease of in-line purification is suitable for hospital use. To date, continuous flow microreactor technology has shown potential for synthesis of [18F]-radiolabeled molecular imaging probes such as [18F]FDG, [18F]fallypride, [18F]annexin, and so on, which were made