10.1080/00397911.2010.515361
The research presents a one-pot oxidation method for alanine and its ethyl ester using the mild oxidant 4′-methylazobenzene-2-sulfenyl bromide. The study focuses on the sulfenylation reaction of L-alanine and its ethyl ester with the oxidant in aqueous solution at room temperature, yielding sulfenimines that, upon acidic hydrolysis, produce ethanal and pyruvic acid, respectively. The experiments involved reacting L-alanine or its ethyl ester with the sulfenyl bromide in the presence of an acid scavenger, triethylamine, to form sulfenimines. These were then hydrolyzed in an acidic medium to obtain the carbonyl compounds. The reactants included L-alanine, its ethyl ester, 4′-methylazobenzene-2-sulfenyl bromide, and triethylamine. Analytical techniques used for characterization included infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, and elemental analysis. The products, acetaldehyde and pyruvic acid, were identified as their 2,4-dinitrophenylhydrazones after isolation.
10.1039/b411545g
The study investigates the effects of side chain homologation on the pairing selectivity and stacking of alanyl peptide nucleic acids (alanyl-PNAs), which are oligomers based on a regular peptide backbone with covalently linked nucleobases. The researchers compared different linkers, such as methylene (alanyl-PNA), ethylene (homoalanyl-PNA), and trimethylene (norvalyl-PNA), to understand how side chain length influences pairing selectivity and base pair stacking. The chemicals used in the study included various nucleo amino acids, such as alanine, homoalanine, and norvaline, which were prepared and oligomerized to form different PNA sequences. These sequences were then tested for their pairing properties and stabilities, allowing the researchers to draw conclusions about the interdependence between recognition, insertion of methylene groups, and the backbone topology. The purpose of these chemical modifications was to selectively manipulate pairing selectivity and base pair stacking, providing insights into the recognition interactions and potential applications of PNAs in molecular biology.
10.1007/s00726-009-0336-6
The research focuses on the microwave-assisted synthesis and characterization of optically active poly(ester-imide)s incorporating L-alanine. The purpose of this study was to develop a series of new poly(ester-imide)s (PEIs) and copolymers (Co-PEIs) that are optically active, thermally stable, and soluble in polar aprotic solvents. These polymers are of interest due to their potential applications in high-performance industries such as microelectronics, aerospace, and automotive, where there is a demand for materials that can replace ceramics or metals. The researchers successfully synthesized these polymers with inherent viscosities ranging from 0.31 to 0.53 dl g?1, which exhibited good optical activity and thermal stability. The key chemicals used in the process included pyromellitic dianhydride, L-alanine, thionyl chloride, polyethyleneglycol-diol (PEG-200), and several synthetic aromatic diols. The research concluded that the incorporation of L-alanine into the polymer structure resulted in materials with improved solubility and processability while maintaining the excellent thermal and mechanical properties characteristic of polyimides.
10.1002/jhet.5570320225
The research aimed to synthesize a series of N'-substituted 1,4-benzodiazepine-1-carbothioamides (2a-j) and investigate their anti-HIV activity. The researchers used a precursor, 1,4-benzodiazepine 11, and reacted it with various N-substituted isothiocyanates or sodium thiocyanate-trifluoroacetic acid to create the target compounds. Key chemicals involved in the synthesis included 2-aminobenzyl alcohol, di-tert-butyl dicarbonate, carbon tetrabromide, triphenylphosphine, L-alanine, and different isothiocyanates. Despite the structural resemblance of these molecules to the potent TIBO-type anti-HIV compound R82150, none of the synthesized compounds displayed anti-HIV activity in vitro, suggesting that the potent anti-HIV activity of TIBO derivatives requires an intact tricyclic structure.
10.1021/jo980821a
The research aims to develop an efficient chemoenzymatic synthesis of enantiopure 4-amino-2-hydroxy acids, which are valuable as ?-turn mimics for studying the secondary structure of peptides. The study employs a single-pot process in an aqueous medium, using carbobenzyloxy (CBZ)-protected 4-amino-2-keto esters derived from L-amino acids (alanine, leucine, phenylalanine, and valine) as substrates. Lipase from Candida rugosa is used to hydrolyze the keto esters to keto acids. The study compares the performance of wild-type lactate dehydrogenases (LDHs) from Bacillus stearothermophilus (BS-LDH) and Staphylococcus epidermidis (SE-LDH) with the genetically engineered H205Q mutant of D-hydroxyisocaproate dehydrogenase (LB-hicDH) in reducing the keto acids to the corresponding 2-hydroxy acids. The wild-type LDHs effectively reduced the alanine-derived keto acid but were inefficient with more bulky substrates. In contrast, the H205Q mutant demonstrated broad substrate specificity and high catalytic activity, successfully reducing all tested keto acids to yield the desired 4-amino-2-hydroxy acids as single diastereomers with excellent yields. The study concludes that the H205Q mutant has significant potential for the large-scale production of these compounds due to its enhanced performance and versatility.
10.1016/j.tetlet.2011.07.078
The research focuses on the stereoselective synthesis of the peptide moiety of jamaicamides, which are marine natural products with sodium channel blocking properties. The synthesis begins with natural amino acids, L-alanine and N-Boc-β-alanine, and utilizes Meldrum's acid as a key reactant. The researchers detail the preparation of two segments of the peptide: the pyrrolidone ring and the N-Boc-β-methoxy enone carboxylic acid. Various reagents such as EDC·HCl, DMAP, NaBH4, and LiHMDS are used in a series of reactions including condensation, reduction, and amide bond formation. Analytical techniques likely employed, though not explicitly mentioned in the paragraph, include NMR spectroscopy and mass spectrometry for compound characterization. The study also discusses alternative routes and yields for different steps, aiming to optimize the synthesis process.
10.1248/cpb.42.580
This study aimed to synthesize N-[(1S)-1-carboxy-5-(4-piperidinyl)pentyl]-L-alanine derivatives and evaluate their inhibitory activity against angiotensin converting enzyme (ACE) in order to find potent and long-lasting ACE inhibitors. Various derivatives were successfully prepared, among which compounds 7a and 8-11 showed potent and long-lasting ACE inhibitory activity in rats. The key synthetic intermediates included N-[(1S)-5-(1-benzyloxycarbonyl-4-piperidinyl)-1-ethoxycarbonylpentyl]-L-alanine (17a), which was synthesized by asymmetric reduction of α-oxoester (13) with Lactobacillus paracasei subsp. paracasei, followed by substitution and treatment with hydrogen chloride. The study concluded that 1-carboxy-5-(4-piperidinyl)pentyl has potent ACE inhibitory activity and a long duration of action, even when combined with different types of α-amino acids. Chemicals used in the process include L-alanine, piperidine, various esters and acids, and Lactobacillus paracasei subsp. paracasei for the asymmetric reduction step.
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