10.3987/COM-04-10206
The research focuses on the development of a new synthetic method for producing 2,3,6-tri- and 2,3,5,6-tetrasubstituted pyridine derivatives, which are key structural components of thiostrepton-type macrocyclic antibiotics. The synthesis is achieved starting from L-α-aspartic acid through the use of an α-dehydroamino acid derivative. The study involves a series of chemical reactions, including esterification, reduction, oxidation, and cyclization, utilizing reagents such as DCC, HOBt, NaBH4, SO3.pyridine, Jones reagent, MnO2, MeI, Ag2CO3, and Pd-C/H2. The analyses used to characterize the synthesized compounds include melting point measurements, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis, which confirm the structure and purity of the products.
10.1080/00397910008086885
The research details a versatile approach to synthesizing protected (S)-aspartimide, (4S)-amino-2-pyrrolidinone, and (3S)-aminopyrrolidine derivatives starting from (S)-aspartic acid. The purpose of this study was to develop a unified method for these structurally related compounds, which are significant due to their presence in various bioactive compounds and their potential use as chiral ligands in asymmetric synthesis. The researchers successfully synthesized (S)-1-benzyl-3-p-toluenesulfonylamino-2,5-pyrrolidinedione, (S)-1-benzyl-3-p-toluenesulfonylaminopyrrolidine, and (S)-1-benzyl-4-p-toluenesulfonylamino-2-pyrrolidinone using a series of reactions involving tosylation, cyclization, and selective reductions. Key chemicals used in the process included (S)-aspartic acid, acetic anhydride, benzylamine, lithium aluminium hydride, sodium borohydride, and various solvents such as ethyl acetate and tetrahydrofuran (THF). The study concluded with the establishment of a useful approach to these compounds, which are valuable building blocks for several bioactive compounds, and noted that further investigation into the use of the synthesized compounds as chiral ligands for asymmetric synthesis is underway.
10.1007/BF00766247
The research investigates the central nervous system (CNS) stimulant effects of N-acyl derivatives of glutamic and aspartic acids. The study explores how these derivatives interact with glutamate-recognizing sites in rat brain synaptic membranes and their convulsive activity when directly injected into the brain. Key chemicals used in the research include N-acyl derivatives of glutamic and aspartic acids (I-XVII), which were synthesized from various starting materials such as phenoxyacetic acid, benzoylpropionic acid, phenylbutyric acid, naphthylacetic acid, and diphenyl-ethoxyacetic acid. Other notable chemicals include glutamic diethyl ether, NMDA (N-methyl-D-aspartic acid), and kainate, which were used to test the convulsive and anticonvulsive activities of the synthesized compounds. The study aims to understand the relationship between the structure of these derivatives and their pharmacological activity, revealing that the presence and arrangement of polar and lipophilic groups in the acyl radical significantly influence their stimulant effects and potential as new pharmacologically active compounds targeting the excitatory amino acid system in the CNS.
10.1007/BF02142154
The study investigates the effects of K and Mg aspartate on cellular metabolism, specifically focusing on oxygen consumption and respiratory CO? production in isolated rat nephrons. The chemicals involved include aspartate, which is proposed to stimulate cellular metabolic processes by potentially acting as an anaerobic generator of CO? or stimulating the tricarboxylic acid cycle after deamination. The study found that the addition of aspartate significantly increased oxygen consumption and CO? production without altering the respiratory quotient, suggesting that aspartate enhances cellular metabolism through its role in producing oxalacetate, a key component of the Krebs cycle. This effect is more complex than simply acting as a cation carrier for K and Mg, and may also involve a vascular action due to the vasodilating effect of oxalacetate on small vessels.
10.1039/b104137c
The research focuses on the protease-catalyzed synthesis of carbohydrate-amino acid conjugates, specifically glycopeptide analogues, through a highly regioselective and carbohydrate-specific process. The purpose of this study was to develop a ready and short route for the creation of ester-linked glycopeptides, which are known to display a wide variety of potent biological activities with potential therapeutic and commercial value. The researchers used amino acid vinyl ester acyl donors and minimally or completely unprotected carbohydrate acyl acceptors to probe the active sites of proteases. They found that the yield efficiencies were modulated by the carbohydrate C-2 substituent, which could be exploited for selective one-pot syntheses. The study successfully established a method for constructing glycan-peptide conjugates with yields ranging from 23–76%, which is comparable to or better than alternative routes employing protection-deprotection strategies. The chemicals used in the process included serine protease subtilisin Bacillus lentus (SBL) as a catalyst, and amino acids such as phenylalanine, aspartic acid, and glutamic acid, along with various carbohydrate acyl acceptors. The research concluded that the protease-catalyzed transesterification process is a powerful method for creating glycopeptides, which can be further extended at their sugar reducing end or peptide N-terminal, and that the substrate specificity of the proteases SBL and TLCLEC showed a strong preference for phenylalanine with flexibility in N-protection.
10.1039/a700650k
The research focuses on the enantioselective synthesis of 2-isocephem and 2-isooxacephem antibiotics, which are nuclear analogues of β-lactam antibiotics and have shown potent antibacterial activity. The purpose of the study was to develop a method for synthesizing enantiomerically pure forms of these compounds, addressing the challenge of constructing cis-oriented chiral centers at the azetidinone ring. The researchers used L-aspartic acid as a chiral starting material and successfully synthesized the target compounds through a series of chemical reactions involving azide introduction, four-component condensation, and intramolecular acylation. Key chemicals used in the process included azido lactone, p-nitrobenzyl isocyanide, formaldehyde, 2,2-diethoxyacetaldehyde, and various protecting and deprotecting agents.
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