The enantioseparation of N-protected fluorenylmethoxycarbonyl (N-FMOC) alpha-amino acids was carried out on three polysaccharide-derived chiral stationary phases, such as cellulose tris(3,5-dimethylphenylcarbamate) (Chiralcel OD), amylose tris(3,5-dimethyl-phenylcarbamate) (Chiralpak AD) and cellulose tris(4-methylbenzoate) (Chiralcel OJ), and the influence of acetonitrile composition and pH of the eluents on the enantioseparation in reverse mode chromatography was examined. The best separation of the enantiomers was achieved with 40% acetonitrile in 50mM phosphate buffer at pH 2. However, increasing the composition of acetonitrile to 50% on Chiralcel OD yielded a considerable decrease of retention time with minimum loss of resolution. The elution order of N-FMOC alpha-amino acid enantiomers on Chiralcel OD and OJ were quite different, indicating that both phases could be used in a complementary manner for the separation of the enantiomers of N-FMOC alpha-amino acids. The positive relationship between the capacity factor of N-FMOC alpha-amino acids and the hydrophobicity of amino acids indicated that hydrophobicity plays an important role on the retention of the N-FMOC alpha-amino acids in the reverse mode.
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http://dx.doi.org/10.1016/j.jpba.2008.01.012 | DOI Listing |
Malting quality of barley is a complex characteristic, which is influenced by a combination of interacting traits that are regulated by various genetic and environmental factors. The activities of various enzymes play pivotal roles in determining the malting quality, as they drive the biochemical processes responsible for converting barley saccharides and proteins into fermentable sugars and amino acids during the malting process. In this study, 14 malting barley cultivars were used to investigate the relationship between enzyme activities and malting quality traits.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii Pr. 31, 119991 Moscow, Russia.
In this work, a series of boronated amidines based on the -dodecaborate anion and amino acids containing an amino group in the side chain of the general formula [BHNHC(NH(CH)CH(NH)COOH)CH], where n = 2, 3, 4, were synthesized. These derivatives contain conserved α-amino and α-carboxyl groups recognized by the binding centers of the large neutral amino acid transporter (LAT) system, which serves as a target for the clinically applied BNCT agent para-boronophenylalanine (BPA). The paper describes several approaches to synthesizing the target compounds, their acute toxicity studies, and tumor uptake studies in vivo in two tumor models.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Compared with chiral β-amino phosphorus compounds, which can be easily derived from natural optically pure α-amino acids, obtaining chiral β-amino phosphorus derivatives remains a challenge. These derivatives, which cannot be derived from chiral natural amino acids, possess unique biological activities or potential catalytic activities. Herein, highly enantioselective hydrogenation for the preparation of chiral β-amino phosphorus derivatives from -β-enamido phosphorus compounds is reported by using a green and low-cost earth-abundant metal nickel catalyst (13 examples of 99% ee).
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemistry, The Citadel, 171 Moultrie Street, Charleston, South Carolina 29409, United States.
We have developed a simple and straightforward synthesis of chiral -imidazolidinone cyclohexenones, featuring six contiguous stereocenters, from feedstock chemicals such as aminophenols, α,β-unsaturated aldehydes, and α-amino acids. Remarkably, this one-pot multicomponent reaction exhibits exceptional diastereoselectivity (>20:1 dr) and relies solely on an amino acid precursor as the chiral source, avoiding the use of transition metals or additional organocatalysts. This reaction is efficient and scalable, enabling synthesis on a gram-scale.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
Water exists in the beginning and hydrates all matter. Life emerged in water, requiring three essential components in compartmentalized spaces: (1) universal energy sources driving biochemical reactions and processes, (2) molecules that store, encode, and transmit information, and (3) functional players carrying out biological activities and structural organization. Phosphorus has been selected to create adenosine triphosphate (ATP) as the universal energy currency, nucleic acids for genetic information storage and transmission, and phospholipids for cellular compartmentalization.
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