- Synthesis and Pharmacological Evaluation of [11C]Granisetron and [18F]Fluoropalonosetron as PET Probes for 5-HT3 Receptor Imaging
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Serotonin-gated ionotropic 5-HT3 receptors are the major pharmacological targets for antiemetic compounds. Furthermore, they have become a focus for the treatment of irritable bowel syndrome (IBS) and there is some evidence that pharmacological modulation of 5-HT3 receptors might alleviate symptoms of other neurological disorders. Highly selective, high-affinity antagonists, such as granisetron (Kytril) and palonosetron (Aloxi), belong to a family of drugs (the "setrons") that are well established for clinical use. To enable us to better understand the actions of these drugs in vivo, we report the synthesis of 8-fluoropalonosetron (15) that has a binding affinity (Ki = 0.26 ± 0.05 nM) similar to the parent drug (Ki = 0.21 ± 0.03 nM). We radiolabeled 15 by nucleophilic 18F-fluorination of an unsymmetrical diaryliodonium palonosetron precursor and achieved the radiosynthesis of 1-(methyl-11C)-N-granisetron ([11C]2) through N-alkylation with [11C]CH3I, respectively. Both compounds [18F]15 (chemical and radiochemical purity >95%, specific activity 41 GBq/μmol) and [11C]2 (chemical and radiochemical purity ≥99%, specific activity 170 GBq/μmol) were evaluated for their utility as positron emission tomography (PET) probes. Using mouse and rat brain slices, in vitro autoradiography with both [18F]15 and [11C]2 revealed a heterogeneous and displaceable binding in cortical and hippocampal regions that are known to express 5-HT3 receptors at significant levels. Subsequent PET experiments suggested that [18F]15 and [11C]2 are of limited utility for the PET imaging of brain 5-HT3 receptors in vivo.
- Mu, Linjing,Müller Herde, Adrienne,Rüefli, Pascal M.,Sladojevich, Filippo,Milicevic Sephton, Selena,Kr?mer, Stefanie D.,Thompson, Andrew J.,Schibli, Roger,Ametamey, Simon M.,Lochner, Martin
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- Preparation methods of 1H-indazol-3-carboxylic acid derivative, granisetron and lonidamine
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The invention relates to preparation methods of a 1H-indazol-3-carboxylic acid derivative, granisetron and lonidamine. The 1H-indazol-3-carboxylic acid derivative is a compound with a structure shown in a formula (1) and a formula (2), and is mainly structurally characterized by having a 1H-indazol-3-carboxylic acid amide skeleton and a 1H-indazol-3-carboxylic ester skeleton. The 1H-indazol-3-carboxylic acid derivative can be synthesized by taking simple o-aminophenylacetic acid amide or o-aminophenylacetic acid ester as an initial raw material. The 1H-indazol-3-carboxylic acid derivative is a key intermediate for synthesizing a plurality of medicines, such as granisetron, lonidamine and the like. The synthesis method of the 1H-indazol-3-carboxylic acid derivative and the drug molecules glassetron and lonidamine is simple, the reaction condition is mild, the reaction speed is high, the yield is high, and purification is easy.
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- Toward biophysical probes for the 5-HT3 receptor: Structure-activity relationship study of granisetron derivatives
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This report describes the synthesis and biological characterization of novel granisetron derivatives that are antagonists of the human serotonin (5-HT3A) receptor. Some of these substituted granisetron derivatives showed low nanomolar binding affinity and allowed the identification of positions on the granisetron core that might be used as attachment points for biophysical tags. A BODIPY fluorophore was appended to one such position and specifically bound to 5-HT3A receptors in mammalian cells.
- Vernekar, Sanjeev Kumar V.,Hallaq, Hasan Y.,Clarkson, Guy,Thompson, Andrew J.,Silvestr, Linda,Lummis, Sarah C. R.,Lochner, Martin
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supporting information; experimental part
p. 2324 - 2328
(2010/07/17)
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- 5-Hydroxytryptamine (5-HT3) Receptor Antagonists. 1. Indazole and Indolizine-3-carboxylic Acid Derivatives
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Metoclopramide (1) is a gastric motility stimulant and a weak dopamine and 5-HT3 receptor antagonist.Conformational restriction of the (diethylamino)ethyl side chain of 1 in the form of the azabicyclic tropane gave 3, a very potent gastric motility stimulant and 5-HT3 receptor antagonist but devoid of significant dopamine receptor antagonist properties.Subsequent alteration of the aromatic nucleus led to the identification of indazoles 6a-h, and 1- and 3-indolizines 7b-d, and 8, and imidazopyridines 9 and 10, as potent 5-HT3 receptor antagonists devoid ofeither dopamine antagonist or gastric motility stimulatory properties.Further conformational restriction of the side chain identified quinuclidine 11 and isoquinuclidine 12 as potent 5-HT3 receptor antagonists which mimic the distorted chair conformation of the tropane with, in the case of 11, the N-methyl group axial.From these series, 6g (BRL 43694) was found to be both potent and selective and has been shown to be a very effective antiemetic agent against cytotoxic drug induced emesis both in the ferret and in man.
- Bermudez, Jose,Fake, Charles S.,Joiner, Graham F.,Joiner, Karen A.,King, Frank D.,et al.
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p. 1924 - 1929
(2007/10/02)
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- Indazolyl carboxylic acid amides useful for treating migraine clusters headache, trigeminal neuralgia or emesis
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Compounds of formula (I) and pharmaceutically acceptable salts thereof: STR1 wherein X is CO and Y is NH; Z is NR3 wherein R3 is hydrogen, C1-6 alkyl, C3-7 alkenyl-methyl, phenyl or phenyl C1-4 alkyl either of which phenyl moieties may be substituted by one or two of halogen, CF3, C1-6 alkoxy or C1-6 alkyl; and Ra is not present; or Z is N and Ra is as defined for R3 above; Rb is present when X-Y-R2 is attached at the phenyl ring and is selected from hydrogen, halogen, CF3, hydroxy, C1-6 alkoxy or C1-6 alkyl; R1 is hydrogen, halogen, CF3, C1-6 alkyl, C1-6 alkoxy, C1-6 alkylthio, C1-7 acyl, C1-7 acylamino, C1-6 alkylsulphonylamino, N(C1-6 alkylsulphonyl)-N-C1-4 alkylamino, C1-6 alkylsulphinyl, hydroxy, nitro or amino, aminocarbonyl, aminosulphonyl, aminosulphonylamino or N-(aminosulphonyl)-C1-4 alkylamino optionally N-substituted by one or two groups selected from C1-6 alkyl, C3-8 cycloalkyl, C3-8 cycloalkyl C1-4 alkyl, phenyl or phenyl C1-4 alkyl groups or optionally N-disubstituted by C4-5 polymethylene; R2 is a group of formula (a) STR2 wherein n is 2 or 3; and R4 is C1-7 alkyl, C3-8 cycloalkyl, C3-8 cycloalkyl-C1-2 alkyl, or a group (CH2)t R6 where t is 1 or 2 and R6 is thienyl, pyrrolyl or furyl optionally substituted by one or two substituents selected from C1-6 alkyl, C1-6 alkoxy, trifluoromethyl or halogen, or is phenyl optionally substituted by one or two substituents having 5-HT antagonist activity and/or gastric motility enhancing activity.
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