Refernces
10.1007/s12039-012-0354-x
The research focuses on the synthesis and evaluation of a series of 2-(3-methyl-2-oxoquinoxalin-1(2H)-yl)acetamide-based azetidinone derivatives as potential antibacterial and antifungal agents. The study involved the synthesis of twelve compounds, which were subjected to in vitro antibacterial testing against E. coli, S. aureus, K. pneumoniae, P. aeruginosa, and antifungal testing against C. albicans, A. niger, and A. flavus using the cup-plate method. The synthesized compounds were confirmed through spectral data interpretation, including Fourier Transform-Infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and elemental analysis. The experiments utilized various reactants such as pyruvic acid, o-phenylenediamine, ethylchloroacetate, potassium carbonate, and different aromatic aldehydes, along with chloroacetylchloride and triethylamine for the final compound formation. The structures of the synthesized compounds were elucidated using these analytical techniques, and their biological activities were assessed and compared with standard drugs to determine their potential as antimicrobial agents.
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.
10.1016/S0040-4039(00)96673-5
This study investigated the synthesis of unusual α-N-hydroxy amino acids through the reaction of organolithium reagents with oximes derived from glyoxylic acid and pyruvic acid. The researchers aimed to develop a direct route to the synthesis of these amino acids to address challenges such as the poor electrophilicity of oximes and the facile α-hydrogenation of substrates. They selected an easily removable oxygen protecting group (R1) and used a free carboxylic acid (R = OH) as an acyl substituent to deactivate the carbonyl group for nucleophilic attack. Alkyl lithium reagents were selected for their strong nucleophilicity. The study found that while magnesium and zinc-based reagents were ineffective, alkyl lithium reagents successfully produced the desired α-N-hydroxy amino acids. The researchers also explored the use of chiral oxime derivatives and observed moderate diastereoselectivity in the reaction. This study provides an efficient and direct method for the synthesis of substituted α-N-hydroxy amino acids with important physiological and synthetic significance.
10.1016/S0040-4039(00)82160-7
The study focuses on the synthesis of isotopically labeled pyrroloquinoline quinone (PQQ), a cofactor found in various microbial dehydrogenases, oxidases, and mammalian copper-containing amine oxidases. The researchers adopted and modified existing chemical synthesis schemes to prepare different isotopically labeled PQQ derivatives, such as 3-13C-PQQ, 3-2H-PQQ, and 8-2H-PQQ. The synthesis of 3-13C-PQQ and 3-2H-PQQ involved the Japp-Klingemann hydrazone synthesis, Fischer indolixation, and Doebner-Von Miller type condensation, using starting materials like methoxy-nitro-aniline and methyl-acetoacetate. For 8-2H-PQQ, a Pfitzinger quinoline synthesis was employed, starting from aminoindole and using reagents like isatin, pyruvic acid, and ceric ammonium nitrate. These isotopically labeled PQQ compounds are valuable for studying the biosynthesis, enzymatic redox catalysis, and physiological role of PQQ in different organisms.
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