2743-60-4Relevant academic research and scientific papers
Research on solubility and bio-solubility of amino acids ionic liquids
Tian, Tian,Hu, Xiaoling,Guan, Ping,Ding, Xiaoqi
, p. 224 - 230 (2017)
Herein, the synthesis of L-(+)-α-(positive butyl)-leucine ethyl ester ionic liquids with anions based on bromide (Br?), terafluoroborate (BF4?) and hexafluorophosphate (PF6?) were presented. The structures and purities of these amino acids ionic liquids (AAILs) were characterized by 1H NMR and the determinations of water content. The interaction energies of AAILs-solvents/amino acids and dipole moment of AAILs were obtained through ab initio at MP2/6-311G?++(2d, p). The relationships between the solubility of AAILs and common solvents, molecular structure and the interaction energies of AAILs-solvents along with the influences of temperature and molecular structure on the bio-solubility of AAILs were discussed systematically. The results revealed that the solubility of the title AAILs increased firstly and then decreased with decreasing dielectric constant of solvent. With the dipole moment of AAILs and hydrogen bond interaction increasing, the solubility in polar solvents had an increasing trend. With the interaction energies of AAILs-solvents becoming bigger, AAILs can be easily dissolved in the solvents. The dissolution of amino acids in AAILs was largened with temperature increasing. Additional, the ease or difficulty of dissolution for amino acids in AAILs can be predicted by theoretical calculation. This prediction is consistent with the dissolution behavior of AAILs.
Stereoretentive N-Arylation of Amino Acid Esters with Cyclohexanones Utilizing a Continuous-Flow System
Ichitsuka, Tomohiro,Komatsuzaki, Shingo,Masuda, Koichiro,Koumura, Nagatoshi,Sato, Kazuhiko,Kobayashi, Shū
supporting information, p. 10844 - 10848 (2021/05/31)
The N-arylation of chiral amino acid esters with minimal racemization is a challenging transformation because of the sensitivity of the α-stereocenter. A versatile synthetic method was developed to prepare N-arylated amino acid esters using cyclohexanones as aryl sources under continuous-flow conditions. The designed flow system, which consists of a coil reactor and a packed-bed reactor containing a Pd(OH)2/C catalyst, efficiently afforded the desired N-arylated amino acids without significant racemization, accompanied by only small amounts of easily removable co-products (i. e., H2O and alkanes). The efficiency and robustness of this method allowed for the continuous synthesis of the desired product in very high yield and enantiopurity with high space-time yield (74.1 g L?1 h?1) and turnover frequency (5.9 h?1) for at least 3 days.
Rh(iii)-Catalyzed diastereoselective transfer hydrogenation: An efficient entry to key intermediates of HIV protease inhibitors
Chen, Gen-Qiang,Lang, Qi-Wei,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie,Wang, Fangyuan,Wu, Ting,Yin, Congcong,Zhang, Xumu,Zheng, Long-Sheng
supporting information, p. 3119 - 3122 (2020/03/23)
A highly efficient diastereoselective transfer hydrogenation of α-aminoalkyl α′-chloromethyl ketones catalyzed by a tethered rhodium complex was developed and successfully utilized in the synthesis of the key intermediates of HIV protease inhibitors. With the current Rh(iii) catalyst system, a series of chiral 3-amino-1-chloro-2-hydroxy-4-phenylbutanes were produced in excellent yields and diastereoselectivities (up to 99% yield, up to 99?:?1 dr). Both diastereomers of the desired products could be efficiently accessed by using the two enantiomers of the Rh(iii) catalyst.
Stereospecific Synthesis of 3,4-Dihydro-2 H-naphtho-1,4-oxazin-2-ones by Unification of Benzoxepine-4-carboxylates with Chiral Amino Acid Ethyl Esters
Bhimapaka, China Raju,Kasagani, Veera Prasad,Kurma, Siva Hariprasad
supporting information, p. 2976 - 2983 (2020/03/23)
A novel and efficient stereocontrolled method has been developed for the preparation of chiral 3,4-dihydro-2H-naphtho[1,2-b][1,4]oxazin-2-ones by the reaction of benzoxepine-4-carboxylates with chiral amino acid ethyl esters for the first time. The chiral 3,4-dihydro-2H-naphtho-1,4-oxazinones have been achieved in one step by the formation of C-N, C-C, and C-O bonds.
Characterization and cytotoxicity evaluation of biocompatible amino acid esters used to convert salicylic acid into ionic liquids
Moshikur, Rahman Md.,Chowdhury, Md. Raihan,Wakabayashi, Rie,Tahara, Yoshiro,Moniruzzaman, Muhammad,Goto, Masahiro
, p. 31 - 38 (2018/05/28)
The technological utility of active pharmaceutical ingredients (APIs) is greatly enhanced when they are transformed into ionic liquids (ILs). API-ILs have better solubility, thermal stability, and the efficacy in topical delivery than solid or crystalline drugs. However, toxicological issue of API-ILs is the main challenge for their application in drug delivery. To address this issue, 11 amino acid esters (AAEs) were synthesized and investigated as biocompatible counter cations for the poorly water-soluble drug salicylic acid (Sal) to form Sal-ILs. The AAEs were characterized using 1H and 13C NMR, FTIR, elemental, and thermogravimetric analyses. The cytotoxicities of the AAE cations, Sal-ILs, and free Sal were investigated using mammalian cell lines (L929 and HeLa). The toxicities of the AAE cations greatly increased with inclusion of long alkyl chains, sulfur, and aromatic rings in the side groups of the cations. Ethyl esters of alanine, aspartic acid, and proline were selected as a low cytotoxic AAE. The cytotoxicities of the Sal-ILs drastically increased compared with the AAEs on incorporation of Sal into the cations, and were comparable to that of free Sal. Interestingly, the water miscibilities of the Sal-ILs were higher than that of free Sal, and the Sal-ILs were miscible with water at any ratio. A skin permeation study showed that the Sal-ILs penetrated through skin faster than the Sal sodium salt. These results suggest that AAEs could be used in biomedical applications to eliminate the use of traditional toxic solvents for transdermal delivery of poorly water-soluble drugs.
The reactions of α-amino acids and α-amino acid esters with high valent transition metal halides: synthesis of coordination complexes, activation processes and stabilization of α-ammonium acylchloride cations
Biancalana, Lorenzo,Bortoluzzi, Marco,Ferretti, Eleonora,Hayatifar, Mohammad,Marchetti, Fabio,Pampaloni, Guido,Zacchini, Stefano
, p. 10158 - 10174 (2017/02/15)
Titanium tetrachloride smoothly reacted with a selection of α-amino acids (aaH) in CH2Cl2 affording yellow to orange solid coordination compounds, 1a-d, in 70-78% yields. The salts [NHEt3][TiCl4(aa)], 2a-b, were obtained from TiCl4/aaH/NEt3 (aa = l-phenylalanine, N,N-dimethylphenylalanine), in 60-65% yields. The complex , 3, was isolated from the reaction of l-proline with NbCl5/NHiPr2, performed in CH2Cl2 at room temperature. The X-ray structure of 3 features a bridging (E)-1,2-bis(3,4-dihydro-2H-pyrrol-5-yl)ethene-1,2-diolate ligand, resulting from the unprecedented C-C coupling between two proline units. Unusually stable α-ammonium acyl chlorides were prepared by the reactions of PCl5/MCln (MCln = NbCl5, WCl6) with l-proline, N,N-dimethylphenylalanine, sarcosine and l-methionine. MX5 (M = Nb, Ta; X = F, Cl) reacted with l-leucine methylester and l-proline ethylester to give ionic coordination compounds, [MX4L2][MX6] (M = Nb, L = Me2CHCH2CH(NH2)CO2Me, X = F, 9; Cl, 11a; M = Nb, X = Cl, , 11c; Ta, 11d), in moderate to good yields. [NbCl5(Me2CHCH2CHNH3CO2Me)][NbCl6], 12, was isolated as a co-product of the reaction of NbCl5 with l-leucine isopropylester, and crystallographically characterized. The reaction of NbCl5 with l-serine isopropylester afforded NbCl3(OCH2CHNHCO2iPr), 13, in 66% yield. The activation of the ester O-R bond was observed in the reactions of l-leucine methyl ester with NbF5 and l-proline ethyl ester with MBr5 (M = Nb, Ta), these reactions proceeding with the release of EtF and EtBr, respectively. All the metal products were characterized by analytical and spectroscopic methods, while DFT calculations were carried out in order to provide insight into the structural and mechanistic aspects.
Design and synthesis of a s-triazene based asymmetric organocatalyst and its application in enantioselective alkylation
Mangawa, Shrawan K.,Singh, Ashawani K.,Awasthi, Satish K.
, p. 61144 - 61147 (2015/08/03)
A very efficient chiral organocatalyst was prepared from the readily available cyanuric chloride. The asymmetric catalyst exhibited a highly enantioselective catalytic performance for the alkylation of a glycinate Schiff base, which provides a useful procedure for the enantioselective synthesis of structurally diverse natural and unnatural α-alkyl-α-amino acids.
Stereochemistry and conformation of skyllamycin, a non-ribosomally synthesized peptide from streptomyces sp. Acta 2897
Schubert, Vivien,Di Meo, Florent,Saaidi, Pierre-Loic,Bartoschek, Stefan,Fiedler, Hans-Peter,Trouillas, Patrick,Suessmuth, Roderich D.
, p. 4948 - 4955 (2014/05/06)
Skyllamycin is a non-ribosomally synthesized cyclic depsipeptide from Streptomyces sp. Acta 2897 that inhibits PDGF-signaling. The peptide scaffold contains an N-terminal cinnamoyl moiety, a β-methylation of aspartic acid, three β-hydroxylated amino acids and one rarely occurring α-hydroxy glycine. With the exception of α-hydroxy glycine, the stereochemistry of the amino acids was assigned by comparison to synthetic reference amino acids applying chiral GC-MS and Marfey-HPLC analysis. The stereochemistry of α-hydroxy glycine, which is unstable under basic and acidic conditions, was determined by conformational analysis, employing a combination of data from NOESY-NMR spectroscopy, simulated annealing and free MD simulations. The simulation procedures were applied for both R- and S-configured α-hydroxy glycine of the skyllamycin structure and compared to the NOESY data. Both methods, simulated annealing and free MD simulations independently support S-configured α-hydroxy glycine thus enabling the assignment of all stereocenters in the structure of skyllamycin and devising the role of two-component flavin dependent monooxygenase (Sky39) as S-selective.
Synthesis and biological activity of mono- and diamides of 2,3-secotriterpene acids
Tolmacheva,Igosheva,Vikharev,Grishko,Savinova,Boreko,Eremin
, p. 186 - 193 (2013/08/23)
Amides of four types were synthesized derived from 2,3-seco-18αH- oleanane and 2,3-secolupane mono- and dicarboxylic acids. The spectrum of diamide derivatives was expanded with C3-C3′ and C28-C28′ biscondensed amides with two A-secotriterpene backbones obtained by the interaction of monocarboxylic A-seco acids with lysine. Among the synthesized monoand diamide derivatives, potential inhibitors of herpes simplex virus type 1 replication were found, namely, some compounds with an ethyl β-alaninate fragment (EC50 8.7 and 4.1 μM). The ethyl β-alaninate diamide was shown to combine antiherpetic and anti-HIV activity (EC50 5.1 μM). For the active compounds, the ratios of maximum tolerable concentrations to EC50 ranged from 9.7 to 40.8. The synthesized amides did not show any marked cytotoxic effects against human rabdomiosarcoma RD TE32, A549 lung carcinoma, and melanoma MS cell lines.
Friedel-Crafts alkylation of natural amino acid-derived pyrroles with CF3-substituted cyclic imines
Shmatova, Olga I.,Shevchenko, Nikolay E.,Balenkova, Elizabeth S.,R?schenthaler, Gerd-Volker,Nenajdenko, Valentine G.
, p. 92 - 93 (2013/05/09)
Natural amino acid-derived ethyl 2-(1-pyrrolyl)alkanoates react with 2-trifluoromethyl-1-azacycloalkenes selectivity at the β-position of the pyrrole moiety to afford ethyl 2-[3-(1-trifluoromethyl-2-azacycloalkyl)pyrrol-1- yl]alkanoates.
