L-phenylalanine Methyl Ester Hydrochloride Research Articles

Manipulation of Charge Dynamics for Efficient and Bright Blue Perovskite Light-Emitting Diodes with Chiral Ligands.

Perovskite light-emitting diodes (PeLEDs) emerge as a promising class of optoelectronic devices for next-generation displays and lighting technology. However, the performance of blue PeLEDs lags far behind that of their green and red counterparts, including the unachieved trade-off between high efficiency and high luminance, severe efficiency roll-off, and unsatisfactory power efficiency. Here, a multi-functional chiral ligand of L-phenylalanine methyl ester hydrochloride is strategically introduced into quasi-two-dimensional perovskites, which can effectively passivate defects, modulate the phase distribution, improve photoluminescence quantum yield, guarantee high-quality film morphology, and enhance charge transport. Furthermore, ladder-like hole transport layers are established, boosting charge injection and balance. The resultant sky-blue PeLEDs (the photoluminescence peak is 493nm, and the electroluminescence peak is 497nm) exhibit an external quantum efficiency of 12.43% at 1000cd m-2 and a record power efficiency of 18.42lm W-1 , rendering that the performance is among the best blue PeLEDs. This article is protected by copyright. All rights reserved.

P‐9.2: High Performance Quasi‐2D Perovskite Cyan‐Blue Light‐Emitting Diodes by Using a Bifunctional Ligand

Despite substantial progress has been achieved in red/near-infrared, green, and blue perovskite light-emitting diodes (PeLEDs), studies on cyan emitting perovskites are still lacking. However, cyan-emitting perovskite materials are of great importance and have many promising applications, especially for high-quality lighting and light communication. Herein efficient cyan-blue PeLEDs simultaneously achieving high luminance and high color stability are fabricated by using a bifunctional ligand, L-Phenylalanine Methyl ester hydrochloride (L-PMEH). It reveals the carboxyl and amine groups would heal charged defects via electrostatic interactions, and the neutral chlorine related defects can be reduced by the aromatic structures. The optimized cyan-blue PeLEDs show a maximum external quantum efficiency (EQE) of 6.17% with an emission peak at 497 nm and a full width at half-maximum of 21 nm as well as CIE coordinates of (0.09, 0.19). The obtained maximum luminance of 6347 cd m–2 is one of the highest values among the efficient and color-stable cyan-blue PeLEDs.

Preparation and Characterization of Water-Insoluble Gardenia Blue Pigment.

Based on molecular simulations, the synthetic route of water-insoluble gardenia blue pigment was prepared by the reaction of genipin and L-Phenylalanine methyl ester hydrochloride. A highly purified pigment was obtained after extraction by chloroform and purification by silica gel column chromatography, and the value of color is up to 288. A study on the structural characteristics of the pigment was implemented with a scanning electron microscope, ultraviolet-visible spectrophotometer, Fourier transform infrared spectrometer, X-ray photoelectron spectrometer, and quatropde-time of flight mass spectrometer. The results showed that the surface of the pigment was largely smooth and spherical; The λmax was 607 nm, and the main functional groups include O-C=O, C=O, C-N, C=C, OH, and benzene ring; We detrained six different molecular weight and chemical structures of pigments and speculated the particular structures and formation mechanisms of three kinds of pigment, whose molecular weights are 690.1156, 720.1226, and 708.1246 Da, respectively. The pigment was only able to be dissolved in ethanol, methanol, acetone, ethyl acetate, and other strong polar organic solvents, but was not able to be dissolved in water, ethyl ether, petroleum ether, and other weak polar organic solvents. In terms of light and thermal stabilities, water-insoluble gardenia blue pigment is significantly better than water-soluble gardenia blue pigment (p < 0.05). When it is under direct light for 7 days or incubated at 80–120 °C for 24 h, the pigment residual rates were 74.90, 95.26, 88.27, and 87.72%, respectively.

Synthesis of Chiral Tetramic Acids: Preparation of (S)-5-Benzylpyrrolidine-2,4-dione from L-Phenylalanine Methyl Ester Hydrochloride.

Synthesis of Chiral Tetramic Acids: Preparation of (S)-5-Benzylpyrrolidine-2,4-dione from L-Phenylalanine Methyl Ester Hydrochloride.

Chemical Modification of Laccase from Aspergillus oryzae and its Application in OCC Pulp

Laccase activity and stability were improved and modified through the interaction between laccase amino acid residues (e.g., amino groups (-NH2) and carboxyl groups (-COOH)) and the chemical reagents thiourea dioxide (TDO) and L-phenylalanine methyl ester hydrochloride (L-PME). Compared with the control sample, the activity of the laccase modified with these chemical reagents was increased by 209% and 50%, respectively. The stability of the laccase modified with L-PME increased by 56.9%. However, the laccase modified with TDO only improved slightly. It was clear that reagent L-PME was more efficacious than TDO. The paper formed with addition of L-PME-modified laccase exhibited better performance in terms of tensile strength, bursting strength, and tear strength, which increased by 13%, 10%, 9%, respectively, compared with the paper formed with unmodified laccase.

Hemicucurbiturils as receptors in extraction and transport of some amino acids

The molecular recognition properties of hemicucurbit[6]uril (HemiCB[6]) and hemicucurbit[12]uril (HemiCB[12]) towards a series of amino acid native and methyl esters (L-phenylalanine, L-leucine, L-valine, L-cysteine, L-tryptophan, L-isoleucine, L-phenylalanine methyl ester hydrochloride (L-PheOMe), L-tyrosine methyl ester hydrochloride (L-TyrOMe), L-valine methyl ester hydrochloride (L-ValOMe), L-leucine methyl ester hydrochloride (L-LeuOMe), L-serine methyl ester hydrochloride (L-SerOMe) and L-cysteine methyl ester hydrochloride (L-CysOMe) were investigated. In this respect, by means of liquid–liquid extraction, a series of amino acid native and methyl esters were extracted from an aqueous phase (pH = 5.5) into a chloroform phase as ion pairs in the presence of tropaeolin 00 as counterion. Based on results obtained in extraction experiments, the active transport assisted by pH gradient of amino acids as ion pairs through chloroform liquid membrane employing HemiCB[6] as carrier was performed. Both receptors used in experiments exhibited extractability towards amino acids under study. From the results obtained, one can observed the good affinity of both receptors, hemiCB[6, 12], towards hydrophobic amino acids (L-PheOMe, L-LeuOMe and L-ValOMe)). It was emphasised that the structure of hemicucurbiturils and amino acids together with the anion nature, and pH have influenced the experimental results.

L-Phenylalanine methyl ester hydrochloride as a green corrosion inhibitor for mild steel in hydrochloric acid solution and the effect of surfactant additive

Structure ofl-phenylalanine methyl ester hydrochloride.

Synthesis and Reactions of New Chiral Linear Dipeptide Candidates Using Nalidixic Acid as Starting Material

A series of dipeptide heterocyclic derivatives 4-15 were synthesized using methyl 2-{[(1-ethyl- 7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridin-3-yl)carbonyl]amino}-3-ethylbutanoate (3) as starting material. Treatment of 3 with L-phenylalanine methyl ester hydrochloride afforded the corresponding dipeptide methyl ester derivative 4, which was treated with hydrazine hydrate to afford the dipeptide acid hydrazide 5. Compound 5 was coupled with aldehyde and acetophenone derivatives to afford the corresponding Schiff bases 6a-f. The hydrazide derivative 5 was reacted with ethyl acetoacetate or acetone to give compounds 7 and 8, respectively. Reaction of 5 with carbon disulfide at different conditions afforded compounds 9 and 10, which were treated with hydrazine hydrate to give the 1-amino-2-dipeptido-1,3,4-triazole derivative 11. In addition, 5 was reacted with phenyl isothiocyanate to give the thiosemicarbazide derivative 12, which was cyclized with sodium hydroxide to the dipeptido 1-phenyl-1,3,4-triazole derivative 13. Finally, treatment of 13 with methyl iodide afforded the S-methyl derivative 14, which was reacted with hydrazine hydrate to give the hydrazine derivative 15.

Screening, purification, and identification of the enzyme producing N-(l-α-l-aspartyl)-l-phenylalanine methyl ester from l-isoasparagine and l-phenylalanine methyl ester

Screening was carried out for microorganisms able to produce N-(l-alpha-l-aspartyl)-l-phenylalanine methyl ester [APM] from l-isoasparagine and l-phenylalanine methyl ester hydrochloride. Of the 422 strains examined, 44 strains belonging to the family Enterobacteriaceae were found to produce APM. The enzyme catalyzing APM production was purified and identified as dipeptidase E.

Ortho Palladation and Functionalization of l-Phenylalanine Methyl Ester

The ortho-metalated complex (S,S)-[Pd2{κ2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(μ-Br)2] (1b) can be prepared by refluxing in acetonitrile equimolecular amounts of Pd(OAc)2 and l-phenylalanine methyl ester hydrochloride, followed by addition of an excess of NaBr. Complex 1b reacts with 4-picoline to give the mononuclear derivative (S)-[Pd{κ2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2Br(NC5H4Me-4)] (2), whose crystal structure has been determined by X-ray diffraction. The precursor of 1b, (S,S)-[Pd2{κ2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(μ-Cl)2] (1a), could not be isolated in a pure form, but it can be used as the starting material for the synthesis of functionalized derivatives of the phenylalanine methyl ester. Thus, CO and RNC (R = Xy, tBu) insert into the Pd−C bond of 1a to afford, after depalladation, (S)-1-oxo-3-(methoxycarbonyl)-1,2,3,4-tetrahydroisoquinoline (3) and (S)-1-R-3-(methoxycarbonyl)-3,4-dihydroisoquinolinium triflate (R = tBu (4), Xy (5)), respectively. Reaction of complex 1b with bromine or iodine affords trans-(S,S)-[PdBr2{NH2CH(CO2Me)CH2C6H4-X-2}2] (X = Br (6), I (7)), which further reacts with 1,10-phenanthroline (phen) to give [PdBr2(phen)] and (S)-2-X-phenylalanine methyl ester (X = Br (8), I (9)).

Preparation of Optically Active (2RS,3SR)-2-Amino-3-hydroxy-3-phenylpropanoic Acid (threo-.BETA.-Phenylserine) via Optical Resolutions by Replacing and Preferential Crystallization

To obtain optically active threo-2-amino-3-hydroxy-3-phenylpropanoic acid (1) via optical resolutions by replacing and preferential crystallization, the racemic structure of (2RS,3SR)-1 hydrochloride [(2RS,3SR)-1.HCl] was examined based on the melting point, solubility, and infrared spectrum. (2RS,3SR)-1.HCl was indicated to exist as a conglomerate at room temperature, although it forms a racemic compound at the melting point. When, in optical resolution by replacing crystallization, L-phenylalanine methyl ester hydrochloride (L-2) was used as the optically active co-solute, (2R,3S)-1.HCl was preferentially crystallized from the supersaturated racemic solution; the use of D-2 as the co-solute afforded (2S,3R)-1.HCl with an optical purity of 95%. In addition, optical resolution by preferential crystallization was successfully achieved to give successively (2R,3S)- and (2S,3R)-1.HCl with optical purities of 90-92%. The (2R,3S)- and (2S,3R)-1.HCl purified by recrystallization from 1-propanol were treated with triethylamine in methanol to give optically pure (2R,3S)- and (2S,3R)-1.

Thermodynamics of Amino Acid Methyl Ester Hydrochlorides—Crown Ether Complexes in Methanol at 25°C

Stability constants, free energies, and enthalpies and entropies of the complexation of L-alanine methyl ester hydrochloride (L-Ala-HCl), L-phenylalanine methyl ester hydrochloride (L-Phe-HCl), and valine methyl ester hydrochloride (L-Val-HCl) with 15-crown-5 (15C5), benzo-15-crown-5 (B15C5), 18-crown-6 (18C6), benzo-18-crown-6 (B18C6), dicyclohexano-18-crown-6 (DC18C6), and dicyclohexano-24-crown-8 (DC24C8) in methanol are reported for 20°C. No significant variation in the stability constants and free energies of complexation is observed, indicating that the various crown ethers are poorly selective in binding the amino acids. However, the nature of the crown ether and the amino acid and their pattern of substitution cause a remarkable variation in the enthalpies and entropies of complexation. This indicates a strong enthalpy–entropy compensation effect. The enthalpy–entropy compensation effect for the crown ether complexes of the amino acid methyl ester hydrochlorides reported herein is compared with that of the crown ethers complexes of the amino alcohols and the free amino acid. It is found that the enthalpy–entropy compensation effect holds equally for the three classes of complexes.

Enzymatic catalysis of formation of Z-aspartame in ionic liquid - An alternative to enzymatic catalysis in organic solvents.

We present the first report of enzymatic catalysis in an ionic liquid. The virtually nonexistent vapor pressure makes ionic liquids an exciting new alternative for enzyme-catalyzed syntheses in environmentally friendly environments. Z-aspartame was synthesized in a thermolysin-catalyzed reaction of carbobenzoxy-L-aspartate and L-phenylalanine methyl ester hydrochloride in 1-butyl-3-methylimidazolium hexafluorophosphate (BP6). Ionic liquids such as BP6 are thermally stable and have a remarkable range of temperatures over which they remain liquid (300 degrees C). With an initial rate of 1.2 +/- 0.1 nmol min(-)(1) mg(-)(1), we observed a competitive rate in comparison to that of enzymatic synthesis in organic solvent. Additionally, the enzyme exhibits outstanding stability, which would normally require immobilization.

Membrane Concentration and Separation of L-Aspartic Acid and L-Phenylalanine Derivatives in Organic Solvents

Abstract The concentration and separation of the amino acids N-benzyloxycarbonyl L-aspartic acid and L-phenylalanine methyl ester hydrochloride in organic solvents have been investigated using reverse osmosis membranes of two types of cellulose acetate, a nanofiltration membrane of polyamide-polyphenylene sulfone (PA-PPSO) composite and a gas separation membrane of polyimide composite in a stirred batch cell. The organic solvents used included primary, secondary, and tertiary alcohols, an ester, and a ketone. There were significant variations in permeate flux, solute rejection, and membrane stability. Usually the rejection of both amino acids was similar; however, certain membrane-solvent combinations gave significantly different levels of rejection. The highest rejection of amino acids (∼0.94) at the lowest pressure of 0.5 MPa was obtained with the PA-PPSO membrane using methanol as a solvent. The cellulose acetate membranes gave reasonable rejection and fluxes but the membrane stability was very poor. The performance of the polyimide composite membrane was good with ethanol but poor with other solvents. The PA-PPSO membrane with methanol as solvent appeared the most promising combination, and the separation performance according to concentration polarization was discussed.

The Pharmacological Activities of the Metabolites ofN‐[(Trimethylamineboryl)‐Carbonyl]‐L‐Phenylalanine Methyl Ester

The metabolites of N-[(trimethylamineboryl)-carbonyl]-L-phenylalanine methyl ester 1 proved to be active in a number of pharmacological screens where the parent had previously demonstrated potent activity. The proposed metabolites demonstrated significant activity as cytotoxic, hypolipidemic, and anti-inflammatory agents. In cytotoxicity screens several of the proposed metabolites afforded better activity than the parent compound against the growth of suspended and solid tumor cell lines. Evaluation of in vivo hypolipidemic activity demonstrated that the proposed metabolites of 1 were only moderately active and were generally less effective than the parent compound. Interestingly, L-phenylalanine methyl ester hydrochloride 3, which contains no boron atom, demonstrated equivalent hypolipidemic activity as the parent at 8 mg/kg/day in CF1 male mice. As anti-inflammatory agents the proposed metabolites demonstrated variable capacities to reduce foot pad inflammation. These compounds were similarly effective as the parent 1 at blocking local pain and were generally better than the parent at protecting CF1 male mice from LPS induced sepsis.

Preparation and Complex Formation of Cyclic Octapeptides Containing L-Proline Residues with Phenylalanine Methylester Hydrochloride.

Cyclic octapeptides, cyclo[L-Tyr(Bzl)-L-Pro]4 (2) and cyclo(L-Tyr-L-Pro)4 (3), were prepared and their conformations investigated. A C2-symmetric conformation containing two cis peptide bonds was found in 2 in CDCl3 and 3 in CD3OD. Cyclo(L-Phe-L-Pro)4 (1) formed a 1 : 1 complex with L-phenylalanine methylester hydrochloride (L-PheOMe·HCl). The 13C-NMR spectra of the complexes of 1 and 2 with 1 eq of D- and L-PheOMe·HCl (D/L ratio=1/2) in CDCl3 displayed separate resonances for several carbon atoms of D-PheOMe·HCl and L-PheOMe·HCl owing to the formation of diastereomeric pairs of the complexes.