17585-69-2Relevant academic research and scientific papers
Asymmetric Synthesis of Functionalized Phenylalanine Derivatives via Rh-Catalyzed Conjugate Addition and Enantioselective Protonation Cascade
Jian, Jia-Hong,Zeng, Hao-Wei,Kuo, Ting-Shen,Wu, Ping-Yu,Wu, Hsyueh-Liang
supporting information, p. 9468 - 9472 (2019/11/28)
The asymmetric conjugate addition of arylboronic acids to N-phthalimidodehydroalanine 1i catalyzed by Rh(I)/L1a enables the facile preparation of chiral functionalized phenylalanines. The reaction proceeds by a conjugate addition and enantioselective protonation cascade, affording a rhodium enolate that undergoes re-face protonation. The reaction tolerates various arylboronic acids and can be used in the gram-scale synthesis of (S)-phenylalanine hydrochloride, demonstrating the reaction scope and the synthetic feasibility of the process.
LAT-1 activity of meta-substituted phenylalanine and tyrosine analogs
Augustyn, Evan,Finke, Karissa,Zur, Arik A.,Hansen, Logan,Heeren, Nathan,Chien, Huan-Chieh,Lin, Lawrence,Giacomini, Kathleen M.,Colas, Claire,Schlessinger, Avner,Thomas, Allen A.
supporting information, p. 2616 - 2621 (2016/05/09)
The transporter protein Large-neutral Amino Acid Transporter 1 (LAT-1, SLC7A5) is responsible for transporting amino acids such as tyrosine and phenylalanine as well as thyroid hormones, and it has been exploited as a drug delivery mechanism. Recently its role in cancer has become increasingly appreciated, as it has been found to be up-regulated in many different tumor types, and its expression levels have been correlated with prognosis. Substitution at the meta position of aromatic amino acids has been reported to increase affinity for LAT-1; however, the SAR for this position has not previously been explored. Guided by newly refined computational models of the binding site, we hypothesized that groups capable of filling a hydrophobic pocket would increase binding to LAT-1, resulting in improved substrates relative to parent amino acid. Tyrosine and phenylalanine analogs substituted at the meta position with halogens, alkyl and aryl groups were synthesized and tested in cis-inhibition and trans-stimulation cell assays to determine activity. Contrary to our initial hypothesis we found that lipophilicity was correlated with diminished substrate activity and increased inhibition of the transporter. The synthesis and SAR of meta-substituted phenylalanine and tyrosine analogs is described.
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.
Recyclable Ligands for the Non-Enzymatic Dynamic Kinetic Resolution of Challenging α-Amino Acids
Nian, Yong,Wang, Jiang,Zhou, Shengbin,Wang, Shuni,Moriwaki, Hiroki,Kawashima, Aki,Soloshonok, Vadim A.,Liu, Hong
supporting information, p. 12918 - 12922 (2015/11/02)
Structurally simple and inexpensive chiral tridentate ligands were employed for substantially advancing the purely chemical dynamic kinetic resolution (DKR) of unprotected racemic tailor-made α-amino acids (TM-α-AAs), enabling the first DKR of TM-α-AAs bearing tertiary alkyl chains as well as multiple unprotected functional groups. Owing to the operationally convenient conditions, virtually complete stereoselectivity, and full recyclability of the source of chirality, this method should find wide applications for the preparation of TM-α-AAs, especially on large scale. The non-enzymatic dynamic kinetic resolution of racemic α-amino acids bearing tertiary alkyl chains and multiple unprotected functional groups is based on the enantioselective formation of nickel(II) complexes and their hydrolysis under convenient conditions. The specially designed chiral ligands are inexpensive and can be quantitatively recycled.
Organocatalytic asymmetric biomimetic transamination of α-keto acetals to chiral α-amino acetals
Pan, Hongjie,Xie, Ying,Liu, Mao,Shi, Yian
, p. 2389 - 2392 (2014/01/06)
This paper describes a chiral base-catalyzed asymmetric biomimetic transamination of α-keto acetals. A wide variety of α-amino acetals containing various functional groups can be synthesized in 50-85% yield and 82-86% ee.
Isolation and structural determination of the antifouling diketopiperazines from marine-derived Streptomyces praecox 291-11
Cho, Ji Young,Kang, Ji Young,Hong, Yong Ki,Baek, Hyo Hyun,Shin, Hyoun Woong,Kim, Myoung Sug
experimental part, p. 1116 - 1121 (2012/10/07)
Marine derived actinomycetes constituting 185 strains were screened for their antifouling activity against the marine seaweed, Ulva pertusa, and fouling diatom, Navicula annexa. Strain 291-11 isolated from the seaweed, Undaria pinnatifida, rhizosphere showed the highest antifouling activity and was identified as Streptomyces praecox based on a 16S rDNA sequence analysis. Strain 291-11 was therefore named S. praecox 291-11. The antifouling compounds from S. praecox 291-11 were isolated, and their structures were analyzed. The chemical constituents representing the antifouling activity were identified as (6S,3S)-6-benzyl-3-methyl-2,5-diketopiperazine (bmDKP) and (6S,3S)-6-isobutyl-3- methyl-2,5-diketopiperazine (imDKP) by interpreting the nuclear magnetic resonance and high-resolution mass spectroscopy data. Approximately 4.8mg of bmDKP and 3.1 mg of imDKP were isolated from 1.2 g of the S. praecox 291-11 crude extract. Eight different compositions of culture media were investigated for culture, the TBFeC medium being best for bmDKP and TCGC being the optimum for imDKP production. Two compounds respectively showed a 17.7 and 21 therapeutic ratio (LC50/EC50) to inhibit zoospores, and two compounds respectively showed a 263 and 120.2 therapeutic ratio to inhibit diatoms.
Cyclopeptides and polyketides from coral-associated fungus, Aspergillus versicolor LCJ-5-4
Zhuang, Yibin,Teng, Xiancun,Wang, Yi,Liu, Peipei,Wang, Hui,Li, Jing,Li, Guoqiang,Zhu, Weiming
experimental part, p. 7085 - 7089 (2011/10/09)
Three new cyclopentapeptides, versicoloritides A-C (1-3), a new orcinol tetramer, tetraorcinol A (4), and two new lactones, versicolactones A and B (5 and 6) together with three known metabolites, diorcinol, glyantrypine, and cordyol C were isolated from the fermentation broth of the coral-associated fungus Aspergillus versicolor LCJ-5-4. Their structures were elucidated by spectroscopic and chemical methods. The new compounds 1-4 were evaluated for their radical-scavenging activity and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Enterobacter aerogenes, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans and cytotoxicity against P388 and Hela cell lines. Compound 4 showed weak radical-scavenging activity against the DPPH radical with an IC50 value of 67 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.
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.
A new method for the preparation of functionalized unnatural α-H-α-amino acid derivatives
Hyett, David J.,Didonè, Mara,Milcent, Thierry J.A.,Broxterman, Quirinus B.,Kaptein, Bernard
, p. 7771 - 7774 (2007/10/03)
A new method for the preparation of α-H-α-amino acids is reported based on the α-alkylation of iminoacetic acid esters or amides. These imines are readily available by the reaction of glyoxylic acid esters with branched primary amines. The subsequent reaction with methanolic ammonia gave the corresponding iminoacetic acid amides. α-Alkylation of these imines with various electrophiles under basic conditions, followed by an acidic hydrolysis, gave α-amino acids, esters, or amides in up to 93% yield. α-Alkylation under chiral PTC conditions resulted in mono-alkylated amino acids with 90% ee.
