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Radiochemistry for Preclinical Imaging Studies
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
For nucleophilic substitution, the precursor contains a suitable leaving group such as chloride, bromide, or tosylate. An alternative is the preparation of the precursor with the stable iodine 127I followed by isotopic substitution with the radioactive isotope 123I. The corresponding two organic compounds are then called isotopologues. Halogen–halogen exchange reactions can be catalyzed by metals, an example is the aromatic Finkelstein reaction that is described in the following paragraph. However, this does not affect the equilibrium concentration ratio of the two organohalide species. In particular, for isotopologues with nearly identical chemical properties, this ratio is rather affected (1) by the small, relative mass difference of the two isotopologues and (2) by the absolute concentrations and their ratio of the two reactants employed in the reaction mixture (i.e., excess level of [123I]iodide compared with the organic precursor). The concentrations can be increased by working with melts instead of solvents (Coenen et al. 2006). Also, the crude product is practically impossible to purify from residual precursor isotopologue because of the chemical similarity and very small molecular weight difference between the isotopologues. Practically, only a low to moderate specific activity can be achieved via the isotopic exchange route (Eersels et al. 2005).
Strategies for introducing sulfur atom in a sugar ring: synthesis of 5-thioaldopyranoses and their NMR data
Published in Journal of Sulfur Chemistry, 2019
At around the same time as Hashimoto et al., Kuzuhara and Takahashi [112], had employed a similar synthetic methodology. They published their findings of the synthesis of 5-thio-l-fucopyranose 134. The synthesis started from methyl d-arabinofuranose tribenzoate 145. After removal of benzoyl groups, the resulting tribenzoate was transformed in three successive steps into partially silylated derivative 146 (Scheme 20). The disilylated derivative was subjected to Swern oxidation to afford the key intermediate pentodialdofuranoside 147. Nucleophilic addition of Me3Al in hexane to d-arabino-pentodialdo-l,4-furanose derivative was achieved to give the corresponding 6-deoxy-d-altrofuranose isomer 148 predominately over the l-galacto isomer. A sulfur atom was introduced at C5 of 6-deoxy-d-altrofuranose derivatives via substitution of a 5-tosylate with KSAc in HMPA with inversion of configuration giving thioacetate 149. 5-thio-l-fucofuranoside derivative 149 was subjected to acetolysis to provide the tetraacetate 150. Finally, compound 150 was deacetylated with NaOMe in MeOH to afford 5-thio-α-l-fucopyranose 134.
Investigation of novel sorafenib tosylate loaded biomaterial based nano-cochleates dispersion system for treatment of hepatocellular carcinoma
Published in Journal of Dispersion Science and Technology, 2021
Raj J. Ahiwale, Bothiraja Chellampillai, Atmaram P. Pawar
Leader of cancer death worldwide, Hepatocellular carcinoma (HCC) is a chief liver malignancy.[1] Various molecular mechanism associated with carcinogenesis are loss of cell cycle or senescence control, dysregulation of apoptosis and liver inflammation. For addressing the mechanism drug targets like multikinase inhibitors, inhibitors of mesenchymal-epithelial transition factor (MET) receptor, angiogenesis inhibitors, PI3K/Akt/mTOR inhibitors have come into existence.[2] Sorafenib tosylate (ST), a salt of sorafenib that inhibits tumor-cell proliferation, angiogenesis, vascularization through activating the tyrosine kinases receptor (RTKs) signaling RAS/RAF/MEK/ERK cascade pathway and upsurges the rate of apoptosis in a varied range of tumor models. It has owned approval by the FDA for the treatment of advanced renal cell carcinoma in 2005 and unsecretable hepatocarcinoma in 2006. After oral administration of ST tablet, it shows the mean relative bioavailability of 38–49%, which can be due to unfavored biopharmaceutical properties such as poor solubility over a wide range of pH (1.2–7.4) making absorption, the rate-limiting step attributed to slow dissolution in GIT, hepatic first-pass effect, large intersubject variability and narrow therapeutic window.[3] The renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC) patient on ST regime identified tongue, throat, teeth pain, fatigue, sleep disturbance, mucositis/stomatitis, shortness of breath, and abnormally increased blood pressure. Furthermore, 60% patient on the regime of ST also revealed ‘‘hand-foot-skin reaction''.[4–9]
Apparent molar volumes and relative viscosity of [C3C1PYR][Br]/[C2OHC1PYR][Br] + H2O
Published in Chemical Engineering Communications, 2021
Qingshan Liu, Fengze Yu, Shurong Hui, Hui Liu
However, the two salts have shown different tendencies to change with respect to given temperature range from Table 6 and Figure 3. In the case of [C3C1PYR][Br] + H2O binary solution, the data increase with given temperature arising. According to literature 19, the result indicate that the ion–ion interaction decrease with temperature increasing. Some ionic liquids (ILs) have also shown the same tendency like the [C3C1PYR][Br] + H2O system, for example, the N,N-dimethyl-N-(3-sulfopropyl)cyclohexylammo-nium tosylate ([CyN1,1PrSO3H][Tos]) + water/methanol (H2O/MeOH) (Cai et al. 2017), pyrrolidonium bisulfate with dimethylsulfoxide (DMSO) (Panda et al. 2016), benzyldimethylammonium propionate with N,N-dimethylformamide (DMF) (Keshapolla et al. 2014), and the salt of 1-butyl-3-methylimidazolium bromide ([Bmim][Br]) + H2O binary (Zafarani-Moattar and Shekaari 2005). The values of decrease with increasing temperature for the [C2OHC1PYR][Br] + H2O systems. According to literature 19, the result indicate that the ion–ion interaction increase with temperature increasing. Some systems have also shown the same result from the literatures, such as 1-alkyl-3-methylimidazolium methyl sulfate (alkyl: ethyl and hexyl, abbreviated name: [Emim][MeOSO3], [Hmim][MeOSO3]) and 1-alkyl-3-methylimidazolium ethyl sulfate (alkyl: hexyl, abbreviated name: [Hmim][EtOSO3]) with water (Shekaari and Armanfar 2011), 1-alkyl-4-(4-sulfobutyl)-1H-1,2,4-triazol-4-ium trifluoromethanesulfonate with water (Singh and Gardas 2018), pyrrolidonium bisulfate with water (Panda et al. 2016), benzyldimethylammonium hexanoate with DMF (Keshapolla et al. 2014), and 1-hexyl-3-methyl-imidazolium bromide ([HMIM][Br]) with water (Shekaari et al. 2008).