17694-98-3Relevant academic research and scientific papers
LAT1 activity of carboxylic acid bioisosteres: Evaluation of hydroxamic acids as substrates
Zur, Arik A.,Chien, Huan-Chieh,Augustyn, Evan,Flint, Andrew,Heeren, Nathan,Finke, Karissa,Hernandez, Christopher,Hansen, Logan,Miller, Sydney,Lin, Lawrence,Giacomini, Kathleen M.,Colas, Claire,Schlessinger, Avner,Thomas, Allen A.
supporting information, p. 5000 - 5006 (2016/10/05)
Large neutral amino acid transporter 1 (LAT1) is a solute carrier protein located primarily in the blood–brain barrier (BBB) that offers the potential to deliver drugs to the brain. It is also up-regulated in cancer cells, as part of a tumor's increased metabolic demands. Previously, amino acid prodrugs have been shown to be transported by LAT1. Carboxylic acid bioisosteres may afford prodrugs with an altered physicochemical and pharmacokinetic profile than those derived from natural amino acids, allowing for higher brain or tumor levels of drug and/or lower toxicity. The effect of replacing phenylalanine's carboxylic acid with a tetrazole, acylsulfonamide and hydroxamic acid (HA) bioisostere was examined. Compounds were tested for their ability to be LAT1 substrates using both cis-inhibition and trans-stimulation cell assays. As HA-Phe demonstrated weak substrate activity, its structure–activity relationship (SAR) was further explored by synthesis and testing of HA derivatives of other LAT1 amino acid substrates (i.e., Tyr, Leu, Ile, and Met). The potential for a false positive in the trans-stimulation assay caused by parent amino acid was evaluated by conducting compound stability experiments for both HA-Leu and the corresponding methyl ester derivative. We concluded that HA's are transported by LAT1. In addition, our results lend support to a recent account that amino acid esters are LAT1 substrates, and that hydrogen bonding may be as important as charge for interaction with the transporter binding site.
Cycloforskamide, a cytotoxic macrocyclic peptide from the sea slug Pleurobranchus forskalii
Tan, Karen Co,Wakimoto, Toshiyuki,Takada, Kentaro,Ohtsuki, Takashi,Uchiyama, Nahoko,Goda, Yukihiro,Abe, Ikuro
, p. 1388 - 1391 (2013/08/23)
A macrocylic dodecapeptide, cycloforskamide, was isolated from the sea slug Pleurobranchus forskalii, collected off Ishigaki Island, Japan. Its planar structure was deduced by extensive NMR analyses and was further confirmed by MS/MS fragmentation analyses. Finally, the absolute configuration was determined by total hydrolysis and chiral-phase gas chromatographic analysis. This novel dodecapeptide contains three d-amino acids and three thiazoline heterocycles and exhibits cytotoxicity against murine leukemia P388 cells, with an IC 50 of 5.8 μM.
Hydration of amino acids from ultrasonic measurements
Burakowski, Andrzej,Gliński, Jacek
experimental part, p. 12157 - 12161 (2011/01/11)
In this paper the results of compressibility of aqueous solutions of amino acids in water and in aqueous HCl and NaOH solutions at 25 °C are presented. The effect of the charged protonated amino groups and deprotonated carboxylic groups on the hydration number was tested. The idea of additivity of the hydration number with the constituents of the solute molecule was successfully applied and discussed.
Micropeptins from an Israeli fishpond water bloom of the cyanobacterium microcystis sp
Zafrir, Ella,Carmeli, Shmuel
experimental part, p. 352 - 358 (2010/08/05)
Seven new natural products, micropeptin MZ845 (1), micropeptin MZ859 (2), micropeptin MZ939A (3), micropeptin MZ925 (4), micropeptin MZ939B (5), micropeptin MZ1019 (6), and micropeptin MZ771 (7), as well as two known micropeptins, cyanopeptolin S (8) and cyanopeptolin SS (9), were isolated from the hydrophilic extract of the cyanobacterium Microcystis sp. that was collected from a fishpond in Kibbutz Ma'ayan Tzvi, Israel, in July 2006. The structures of the pure natural products were elucidated using spectroscopic methods, including UV, 1D and 2D NMR, and MS techniques. The absolute configuration of the chiral centers of the compounds was determined using Marfey's method for HPLC. The inhibitory activity of the compounds was determined for the serine proteases: trypsin, chymotrypsin, thrombin, and elastase. These micropeptins inhibited trypsin with IC50's that varied between 0.6 and 24.2 μM. The SAR of these micropeptins is discussed.
Novel cyclopeptide and unique flavone from Desmos rostrata. Total synthesis of desmorostratone
Nguyen, Ngoc Tuan,Pham, Van Cuong,Litaudon, Marc,Guéritte, Fran?oise,Bodo, Bernard,Nguyen, Van Tuyen,Nguyen, Van Hung
experimental part, p. 7171 - 7176 (2009/12/24)
Two new compounds, a cyclic peptide desmocyclopeptide (1) and a special flavone desmorostratone (2) were isolated from the stem bark of Desmos rostrata, along with two known compounds, desmosdumotins B (3) and C (4). Their structures were established on the basis of the spectral data, including mass spectrometry and 2D NMR. The total synthesis of desmorostratone (2) was performed in order to confirm its structure as well as that of desmosdumotin C (4), which was a tautomeric mixture in the solution. Finally, cytotoxity of these compounds were evaluated. Desmosdumotin C (4) displayed a moderate inhibition activity against KB cell line with an IC50 of 19.2 μM, whereas the other products showed a weak inhibition against the same cell line target.
Resolution of DL-racemic mixtures
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Page column 8-9, (2008/06/13)
The present invention relates to a process for the resolution of DL-racemic mixtures of compounds which crystalize in the form of a conglumerate. Both, the D and L-enantiomers are obtained according to the invention in a industrially feasable process by adding chiral enantioselective polymers to the supersaturated solution of the racemat to inhibit crystalization of one enantiomer. Next a DL-racemic mixture of said compound is suspended in about twice the amount of the crystallized enantiomer. Consequently, the opposite enantiomer could be recovered by said suspension by physical separation.
Preparation and Characterization of [5-13C]-(2S,4R)-Leucine and [4-13C]-(2S,3S)-Valine - Establishing Synthetic Schemes to Prepare Any Site-Directed Isotopomer of L-Leucine, L-Isoleucine and L-Valine
Siebum, Arjan H. G.,Woo, Wei Sein,Lugtenburg, Johan
, p. 4664 - 4678 (2007/10/03)
In this paper a chemo-enzymatic method has been developed that gives access to any isotopomer of the essential amino acids isoleucine and valine. The method gives the correct introduction of the second chiral center in (2S,3S)-isoleucine and allows for discrimination between the two prochiral methyl groups in valine as shown by the preparation of (2S,3S)-[4- 13C] valine. For the preparation of (2S)-leucine in any isotopomeric form, the O'Donnell method to prepare optically active amino acids has been used. The protected glycine scaffold used in this method has been prepared by a strategy that allows access to any isotopomeric form. The preparation of [5-13C]-(2S,4R)-leucine shows that the O'Donnell method in combination with the Evans method to obtain chiral 2-methylpropyl iodide leads to a good discrimination between the two prochiral methyl groups. The O'Donnell strategy for the preparation of α-amino acids is preferred over other methods since the reaction conditions are mild, the chiral auxiliary can be easily recovered and the optically active product can be easily separated. For the preparation of isotopically enriched valine and isoleucine the O'Donnell method is not suitable, because the alkyl substituents involved have a secondary halide substituent which is sterically too hindered to give an effective reaction with the protected glycine. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Aminosaeuren, I. Darstellung von Aminosaeuren aus Halogencarbonsaeure-alkylestern mit Alkalimetallcyanaten
Effenberger, Franz,Drauz, Karlheinz,Foerster, Siegfried,Mueller, Wolfgang
, p. 173 - 189 (2007/10/02)
α- and ω-halo- as well as α,ω-dihalocarboxylic alkyl esters react with potassium cyanate in the presence of alcohol at 80 - 120 deg C in dipolar aprotic solvents to yield α- and ω-(alkoxycarbonylamino)- and α,ω-bis(alkoxycarbonylamino)carboxylic alkyl esters, respectively, in good yields.Hydrolytic cleavage of these mono- or diurethanes with an aqueous solution of hydrochloric acid/formic acid leads to the corresponding amino acid hydrochlorides in nearly quantitative yields.
