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1.
Radiofluorination of a Pre‐formed Gallium(III) Aza‐macrocyclic Complex: Towards Next‐Generation Positron Emission Tomography (PET) Imaging Agents 下载免费PDF全文
Dr. Rajiv Bhalla Prof. William Levason Dr. Sajinder K. Luthra Dr. Graeme McRobbie George Sanderson Prof. Gillian Reid 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4688-4694
As part of a study to investigate the factors influencing the development of new, more effective metal‐complex‐based positron emission tomography (PET) imaging agents, the distorted octahedral complex, [GaCl(L)]?2 H2O has been prepared by reaction of 1‐benzyl‐1,4,7‐triazacyclononane‐4,7‐dicarboxylic acid hydrochloride (H2L?HCl) with Ga(NO3)3?9 H2O, which is a convenient source of GaIII for reactions in water. Spectroscopic and crystallographic data for [GaCl(L)]?2 H2O are described, together with the crystal structure of [GaCl(L)]?MeCN. Fluorination of this complex by Cl?/F? exchange was achieved in high yield by treatment with KF in water at room temperature over 90 minutes, although the reaction was complete in approximately 30 minutes if heated to 80 °C, giving [GaF(L)]?2 H2O in good yield. The same complex was obtained by hydrothermal synthesis from GaF3?3 H2O and Li2L, and has been characterised by single‐crystal X‐ray analysis, IR, 1H and 19F{1H} NMR spectroscopy and ESI+ MS. Radiofluorination of the pre‐formed [GaCl(L)]?2 H2O has been demonstrated on a 210 nanomolar scale in aqueous NaOAc at pH 4 by using carrier‐free 18F?, leading to 60–70 % 18F‐incorporation after heating to 80 °C for 30 minutes. The resulting radioproduct was purified easily by using a solid‐phase extraction (SPE) cartridge, leading to 98–99 % radiochemical purity. The [Ga18F(L)] is stable for at least 90 minutes in 10 % EtOH/NaOAc solution at pH 6, but defluorinates over this time scale at pH of approximately 7.5 in phosphate buffered saline (PBS) or human serum albumin (HSA). The subtle role of the Group 13 metal ion and co‐ligand donor set in influencing the pH dependence of this system is discussed in the context of developing potential new imaging agents for PET. 相似文献
2.
Eileen Ryan Catherine Quynh Nhu Nguyen Christopher Shiea Gavin E. Reid 《Journal of the American Society for Mass Spectrometry》2017,28(7):1406-1419
Sphingolipids serve not only as components of cellular membranes but also as bioactive mediators of numerous cellular functions. As the biological activities of these lipids are dependent on their structures, and due to the limitations of conventional ion activation methods employed during tandem mass spectrometry (MS/MS), there is a recognized need for the development of improved structure-specific methods for their comprehensive identification and characterization. Here, positive-ionization mode 193 nm ultraviolet photodissociation (UVPD)-MS/MS has been implemented for the detailed structural characterization of lipid species from a range of sphingolipid classes introduced to the mass spectrometer via electrospray ionization as their lithiated or protonated adducts. These include sphingosine d18:1(4E), dihydrosphingosine (sphinganine) d18:0, sphingadiene d18:2(4E,11Z), the isomeric sphingolipids ceramide d18:1(4E)/18:0 and dihydroceramide d18:0/18:1(9Z), ceramide-1-phosphate d18:1(4Z)/16:0, sphingomyelin d18:1(4E)/18:1(9Z) the glycosphingolipids galactosyl ceramide d18:1(4E)/24:1(15Z) and lactosyl ceramide d18:1(4E)/24:0, and several endogenous lipids present within a porcine brain total lipid extract. In addition to the product ions formed by higher energy collision dissociation (HCD), UVPD is shown to yield a series of novel structurally diagnostic product ions resulting from cleavage of both sphingosine carbon–carbon and acyl chain carbon–carbon double bonds for direct localization of site(s) of unsaturation, as well as via diagnostic cleavages of the sphingosine backbone and N–C amide bond linkages. With activation timescales and dissociation efficiencies similar to those found in conventional MS/MS strategies, this approach is therefore a promising new tool in the arsenal of ion activation techniques toward providing complete structural elucidation in automated, high-throughput lipid analysis workflows. 相似文献
3.
Holly E. Bonfield Dr. Damien Valette Dr. David M. Lindsay Dr. Marc Reid 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(1):158-174
Exploration of novel, three-dimensional chemical space is of growing interest in the drug discovery community and with this comes the challenge for synthetic chemists to devise new stereoselective methods to introduce chirality in a rapid and efficient manner. This Minireview provides a timely summary of the development of palladium-catalyzed asymmetric redox-relay Heck-type processes. These reactions represent an important class of transformation for the selective introduction of remote stereocenters, and have risen to prominence over the past decade. Within this Minireview, the vast scope of these transformations will be showcased, alongside applications to pharmaceutically relevant chiral building blocks and drug substances. To complement this overview, a mechanistic summary and discussion of the current limitations of the transformation are presented, followed by an outlook on future areas of investigation. 相似文献
4.
An iodine-catalyzed direct cycloalkenylation of dihydroquinolines and arylamines has been developed. This method consists of a Friedel–Crafts reaction between dihydroquinolines (or arylamines) and cyclic ketones in which the double bond is selectively generated throughout the course of the reaction resulting in a direct cycloalkenylation, under neat conditions. 相似文献
5.
Nigel M. Groome Elghareeb E. Elboray Dr. Martyn W. Inman Prof. H. Ali Dondas Dr. Roger M. Phillips Colin Kilner Prof. Ronald Grigg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(6):2180-2184
Naturally occurring indole‐3‐carbinol and 3,3‐diindolylmethane show bioactivity in a number of disparate disease areas, including cancer, prompting substantial synthetic analogue activity. We describe a new approach to highly functionalised derivatives that starts from allene gas and proceeds via the combination of a three‐component Pd0‐catalysed cascade with a one‐pot, three‐component carbophilic PtII cascade linked to a stereoselective acid‐catalysed Mannich–Michael reaction that generates complex cyclopropyl diindolylmethanes which show selective activity against prostate cancer cell lines. 相似文献
6.
Prof. Dr. William J. Kerr Dr. Marc Reid Dr. Tell Tuttle 《Angewandte Chemie (International ed. in English)》2017,56(27):7808-7812
We report the first direct catalytic method for formyl-selective deuterium labeling of aromatic aldehydes under mild conditions, using an iridium-based catalyst designed to favor formyl over aromatic C−H activation. A good range of aromatic aldehydes is selectively labeled, and a one-pot labeling/olefination method is also described. Computational studies support kinetic product control over competing aromatic labeling and decarbonylation pathways. 相似文献
7.
Mass spectral analysis of carbohydrates has become an important tool for the biological chemist1–3 and the use of mass spectrometers interfaced with gas-liquid chromatographs has provided a convenient method of study for volatile derivatives of carbohydrates. Several groups4–7 have accomplished separations of the various isomeric trimethylsilyl (TMSi) esters and ethers of the glucuronic acids. The present work utilizes a gas-liquid chromatograph-mass spectrometer to examine the previously unreported mass spectra of pertrimethylsilylated glucuronic acids and these spectra are compared to the previously reported8 spectra of the pemethylated glucuronic acids. 相似文献
8.
In a previous paper the authors, together with Balwant Singh, introduced an elementwisc characterization of weak subintegrality for an extension A?B of commutative rings. In the present paper we improve our methods for working with this characterization. This leads us to propose two new types of “elementary weakly subintegral extension”. 相似文献
9.
Naidong Ye Dan A. Smith J. Gregory Reid David R. Watson Pankaj Daga Stephen E. Gottschling 《合成通讯》2017,47(5):481-485
Incorporation of isotopes has long been used as a research tool to label carbons and elucidate biochemical pathways. More recently, H→D exchange has led to analogs of therapeutic agents with improved metabolic stability and properties. Such compounds also have the potential for an improved drug/drug interaction profile and may even avoid the formation of toxic metabolites. Hence, a clear need for an efficient access to deuterated intermediates on large scale has emerged. In the context of an ongoing drug discovery program, we required large quantities of morpholine-d8. We herein report the successful optimization of a one-pot process allowing a near complete exchange of all methylene hydrogens in morpholine to deuterium atoms using D2O as the sole source of deuterium and Raney Nickel as catalyst. This facile and safe protocol will be used to scale up the synthesis of morpholine-d8 in due course. 相似文献
10.
Andrew L. Hector William Levason Mark E. Light Gillian Reid Kripasindhu Sardar Wenjian Zhang 《无机化学与普通化学杂志》2013,639(6):906-910
Crystalline CrOCl3 contains [Cl2OCr(μ‐Cl)2CrOCl2] molecules with two square pyramidal CrOCl4 units sharing a common edge and with the Cr–O arranged anti, a new structure type for transition metal MOX3 compounds. Crystals are monoclinic with space group P21/c, Z = 4, with a = 5.735(5), b = 13.738(7), c = 11.318(4) Å, α = 90°, β = 98.346(6)°, γ = 90°. Its IR and UV/Vis spectra are reported and compared with those of the C3v monomer found in the gas phase. Structures are also reported for M2[CrOCl5] (M = Cs or Rb) and show a pseudo‐octahedral anion. Cs2[CrOCl5] adopts a K2PtCl6‐type structure with [CrOCl5]2– ions randomly orientated, but Rb2[CrOCl5] is orthorhombic with space group Pnma with a = 13.6471(7), b = 9.9175(5), and c = 6.9562(4) Å. Rietveld refinement of the data on the rubidium salt gave Cr–O = 1.628(1), Cr–CltransO = 2.652(7), Cr–CltransCl = 2.239(8)–2.342(3) Å. Corresponding CrV oxide bromide species do not form. 相似文献