2040-77-9Relevant academic research and scientific papers
Isatin N-phenylsemicarbazone: Effect of substituents and concentration on anion sensing selectivity and sensitivity
Cig, Marek,Jakusov, Klaudia,Donovalov, Jana,Sz?cs, Vojtech,Gplovsk, Anton
, p. 54072 - 54079 (2015/01/09)
The effect of substituent and concentration on anion sensing selectivity and sensitivity of nine new easily synthesized isatin N-phenylsemicarbazone E-isomer sensors IIIa-XIa was investigated. The substantial difference between the association constants for IIIa-XIa interaction with strongly and weakly basic anions allows detection of F- or CH3COO- anions even at high weakly basic anion excess. Substitution in position 5- of the isatin ring and para-substitution on the phenyl ring in the phenylsemicarbazide chain influence sensor:anion complex stoichiometry and thus also sensor sensitivity. Detection limits of 3-4 × 10-7 mol dm-3 for F- and CH3COO- anions by sensors IVa and Va bearing electron-withdrawing substituents are among the lowest published detection limits for these anions in organic solvents. The high selectivity and sensitivity of sensor VIa allows confident F- detection at tolerated fluoride drinking-water level. The solution dilution leads to a dramatic change in sensor selectivity. Consequently, one E-isomer can be used to sense both strongly and weakly basic anions. On the other side, higher sensor solution concentrations increase the F- and CH3COO- anion detection range, similar to the additional Z-isomer utilization. This journal is
Synthesis, labelling and evaluation of hydantoin-substituted indole carboxylic acids as potential ligands for positron emission tomography imaging of the glycine binding site of the N-methyl- d -aspartate receptor
Bauman,Piel,Hoehnemann,Krauss,Jansen,Solbach,Dannhardt,Roesch
experimental part, p. 645 - 656 (2012/01/06)
The N-methyl- d-aspartate (NMDA) receptor as a type of ionotropic glutamatergic receptors is essential for physiological processes such as learning, memory and synaptic plasticity. A glutamate-induced overactivation of these receptors, accompanied by increased intracellular calcium concentration, causes cell injury and leads to a large number of acute or chronic neurological disorders, such as stroke, trauma, Parkinson's disease and Alzheimer's disease. In an attempt to visualise the glutamatergic neurotransmission in vivo with positron emission tomography, novel fluoroethoxy- and methoxy-substituted reference compounds based on the lead structure of a hydantoin-substituted indole-2-carboxylic acid were synthesised. The affinities towards the glycine binding site of the NMDA receptor showed Ki values between 322 and 11 nM and the lipophilicities ranged from logD values of 1.51 to 2.53. On the basis of these results, precursor compounds were synthesised containing a phenolic hydroxy moiety to obtain the radiolabelled ligands through an alkylation reaction. Radiosynthesis was achieved by labelling the precursor ethyl 4,6-dichloro-3-((3-(4-hydroxyphenyl)-2,4-dioxoimidazolidin-1-yl)methyl)- indole-2-carboxylate with 2-[18F]fluoroethyl tosylate or [ 11C]methyl iodide and subsequent cleavage of the ethyl ester moiety. This gave the final products in overall decay-corrected radiochemical yields of 5-7% and 6-9% and specific activities of 24-67 GBq/μmol and 8-26 GBq/μmol, respectively. Copyright
Arylcarbamate derivatives of 1-piperidineethanol as potent ligands for 5-HT4 receptors
Soulier, Jean-Louis,Yang, Donglai,Brémont, Béatrice,Croci, Tiziano,Guzzi, Umberto,Langlois, Michel
, p. 1755 - 1761 (2007/10/03)
A series of carbamate derivatives (7) of 2-(1-piperidinyl)ethyl 4- amino-5-chloro-2-methoxybenzoates, which have been described as potent agonists and antagonists of 5-HT4 receptors, were synthesized. They were evaluated using radioligand binding assays with [3H]GR 113808, a 5-HT4 receptor selective ligand, in the rat striatum and the electrically stimulated myenteric plexus longitudinal muscle of the guinea pig. In contrast to the previously described ester derivatives, a drop in the affinity for 5-HT4 receptors was observed and the compounds were inactive as agonists in the guinea pig ileum preparation. Unexpectedly, the ortho- substituted carbamates 8b,c (R' = H, RO = MeO or EtO, R'' = H) had nanomolar affinity for 5-HT4 receptors (K(i) = 8.9 ± 0.5 and 2.6 ± 0.4 nM, respectively). As reported previously, the cis- or trans-3,5-dimethyl substitution of piperidine (8n,o) was particularly favorable (K(i) = 1.1 ± 0.6 nM for both isomers). 8c is an antagonist equipotent to the 5-HT4 receptor antagonist SDZ 205-557 (1).
