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Breast Imaging with Positron Emission Tomography
Published in Raymond Taillefer, Iraj Khalkhali, Alan D. Waxman, Hans J. Biersack, Radionuclide Imaging of the Breast, 2021
Hans Bender, Holger Palmedo, Hans J. Biersack, Axel Schomburg
FDG is a structural analog of 2-deoxyglucose (2-DG). 18F is attached to the 2-position of this molecule and thus behaves similar to 2-DG. 18F is introduced by nucleophilic substitution of 1,3,4,6-tetra-0-acetyl-2-0-trifluoromethyl-sulfonyl-β-D-mannopyranose (mannose triflate) under stereospecific SN2 reaction conditions. The acetyl groups are removed from the molecule by acidic hydrolization, and FDG can be purified by chromatographic methods with buffered saline solution. After Filtration through a 0.22-μm filter, a sterile, isotonic, neutral 2-[18F] FDG solution is obtained, which is ready for intravenous injection, following quality control and dose calibration. The product is a no-carrier added solution with >95% of the radioactivity represented by 2-[18F]-fluoro-2-deoxy-D-glucose [41]. The specific activity ranges from 27 to 2700 mCi/μmol (1 to 100 GBq/μmol). Noteworthy, 18F-FDG is usually produced employing semi- or fully automated synthesis modules in a dedicated radiopharmacy.
The Chemical Synthesis of Lipid A
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
Shoichi Kusumoto, Koichi Fukase, Masato Oikawa
The 3-hydroxy group in the fatty acid was normally protected as its benzyl ether. A quite efficient method was described for reductive O-benzylation of 3-hydroxy fatty acid esters with the aid of benzaldehyde and triethylsilane in the presence of trimethylsilyl triflate and hexamethydisiloxane (Fig. 2) (16).
New Biological Targets for the Treatment of Leishmaniasis
Published in Venkatesan Jayaprakash, Daniele Castagnolo, Yusuf Özkay, Medicinal Chemistry of Neglected and Tropical Diseases, 2019
Fabrizio Carta, Andrea Angeli, Christian D.-T. Nielsen, Claudiu T. Supuran, Agostino Cilibrizzi
The application of a chiral ferrocene-based ligand (i.e., ‘MandyPhos’) facilitated chirality transfer yielding the products in high enantioselectivity. Notably, alkyl lithium reagents well as vinyl triflates could be used as in the 1,2 metallate rearrangement. To allow facile workup, the boron containing product was oxidized to the alcohol prior to isolation; however, the boron containing product could also be isolated in slightly diminished yields.
Evaluation of WO2017018805: 1,3,4-oxadiazole sulfamide derivatives as selective HDAC6 inhibitors
Published in Expert Opinion on Therapeutic Patents, 2018
Yuan-Yuan Liang, Cheng-Mei Zhang, Zhao-Peng Liu
A detailed synthetic example illustrates the preparation of compound (2) is shown in Figure 1. The activation of N,N-sulfuryldiimidazole was readily achieved by treatment it with methyl triflate in an ice-cooled methylene chloride solution to give the resulting triflate salt as a white solid in 91.5% yield. The imidazolium group of the triflate salt was next displaced with tert-butyl piperazine-1-carboxylate in acetonitrile to afford the corresponding imidazoylsulfonylurea as a beige solid in moderate yield (56.9%). A second activation with methyl triflate then afforded the desired triflate salt almost quantitatively (95.6%). The activated imidazolium group of the triflate salt was next replaced by 3-chloro-4-fluoroanline to generate the corresponding sulfonylurea in 57.7% yield. The sulfonylurea was treated with NaH in N,N-dimethylformide (DMF) at room temperature for 10 min andreacted with methyl 6-bromomethylnicotinate at 50°C for 18 h tointroduc the substituted pyridine ring (45.9%). The Boc protective group was removed by the treatment with 4 M HCl in dioxane to give the hydrochloride salt as a red solid (97.4%). The substitution of the piperazine amino group with an oxetan-3-yl group was carried out through the reaction of the corresponding hydrochloride salt with oxetan-3-one in methylene chloride in the presence of sodium triacetoxyborohydride in 98.6% yield. The methyl nicotinate derivative was further reacted with hydrazine monohydrate in ethanol/water (4/1) solution to give the nicotinohydrazide as a white solid (34.4%). Finally, the 1,3,4-oxadiazole sulfamide derivative 2 with a patent number of 11672 was obtained in 53.9% yield by the treatment of the nicotinohydrazide in tetrahydrofuran (THF) with 2,2-difluoroacetic anhydride in the presence of triethylamine at 80°C for 1 h.