3339-73-9Relevant academic research and scientific papers
Crystal structure, thermal, luminescent and terahertz time domain spectroscopy of magnesium N-phthaloyl-β-alaninate: A combined experimental and theoretical study
Nadeem, Muhammad,Bhatti, Moazzam H.,Sayin, Koray,Yunus, Uzma,Mehmood, Mazhar,Mehboob, Shoaib,Fl?rke, Ulrich
, p. 1 - 8 (2018)
A magnesium complex using N-phthaloyl-β-alanine (NPA) as ligand was synthesized and its crystal structure was characterized by single-crystal X-ray diffraction analysis. The Fourier transformation infrared spectroscopy (FTIR), thermogravimetry (TG) and differential thermal analysis (DTA), fluorescence spectroscopy and terahertz time-domain spectroscopy (THz-TDS) were performed for magnesium N-phthaloyl-β-alaninate (MgNPA). The coordination geometry around Mg (II) has found to be distorted octahedral and the coordination mode of NPA in MgNPA is monodentate i.e. η1μ1. The significant enhancement was observed in the emission intensity of MgNPA complex as compared to the ligand NPA during solid state photoluminescence spectroscopy. The computational investigations of the complex were carried out at B3LYP/6-31 + G (d,p) level in gas phase to support our experimental results. The small energy gap between frontier molecular orbitals (FMOs) manifested that MgNPA is a very reactive, chemically soft and optically active complex. The terahertz time domain spectroscopy of the complex and ligand was performed in order to characterize as well as to find out refractive index and absorption coefficient in 0.2–3.2 THz frequency range. Both the complex and ligand shows the characteristic absorption peaks in this frequency range. The decrease in refractive index is observed by the complexation of NPA with Mg.
Synthesis and characterization of unique new lithium, sodium and potassium coordination polymers
Nadeem, Muhammad,Bhatti, Moazzam H.,Yunus, Uzma,Mehmood, Mazhar,Asif, Hafiz Muhammad,Mehboob, Shoaib,Fl?rke, Ulrich
, p. 179 - 188 (2018)
Five new alkali metal coordination compounds [Li(NPG)](1a), [Na(NPG)2]?2H2O(2a), [C8H5KO4](3a), [Li(NPA)2H2O](1b) and [Na(NPA)2](2b) wherein (NPG = N-phthaloyl glycine, NPA = N-phthaloyl-?-alanine) have been synthesized and characterized by means of X ray single crystal analysis, Infrared spectroscopy (IR), Thermogravimetric analysis (TGA) and Florescence spectroscopy. The compounds 1a, 2a, 3a and 2b showed metal directed self-assembly supramolecular network structures. The crystal structure of compounds 1a and 1b showed distorted tetrahedral geometry with coordination number 4 around lithium. The carboxylate coordination modes were η2μ3and η1μ1 in 1a and 1b respectively. The compounds 2a and 2b exhibited distorted octahedral geometry with coordination number 6 around sodium. The carboxylate coordination mode in 2a and 2b is η2μ2. The objective was to synthesize potassium complex [K(NPG)], but N-phthaloyl glycine was hydrolysed due to exothermic reaction in the presence of strong base, resulted, the formation of 3a. The multiple coordination modes of alkali metal ions to the carboxylate and ring carbonyl oxygen atoms of NPG and NPA produced unique three dimensional architectures. The compounds 1b and 2b showed two strong fluorescence emissions enhancement (blue emission maxima) with greater intensity comparative to NPA, while the compounds 1a and 2a showed two weak fluorescence emissions with less intensity comparative to ligand (NPG). The base hydrolysis of NPG with in the compound 3a resulted the change of ligand based fluorochrome, which produced different shape emission spectrum as compared to other compounds.
Thiamin Biosynthesis in Yeast. Origin of the Five-Carbon Unit of the Thiazole Moiety
White, Robert L.,Spenser, Ian D.
, p. 4934 - 4943 (1982)
Radioactivity from D--, D--, and D-glucose, from D-fructose, and from glycerol is incorporated nonrandomly into the C5 chain of the thiazole moiety of thiamin in Saccharomyces cerevisiae.The incorporation pattern leads to inference that the C5 chain is derived from a 2-pentulose, which is generated from the hexose precursors by the oxidative as well as by the nonoxidative pentose phosphate pathway.A chemically rational scheme for the biogenesis of the thiazole moiety of thiamin is presented.
Convergent Route to β-Amino Acids and to β-Heteroarylethylamines: An Unexpected Vinylation Reaction
Chen, Xuan,Zard, Samir Z.
supporting information, (2020/05/05)
Various protected β2-amino acids can be prepared by radical addition of β-phthalimido-α-xanthyl propionic acid, both as the free acid or as the ethyl ester. Successive radical additions provide access to more complex structures. In the case of the free acid, addition to certain heteroaromatics leads directly to β-heteroarylethylamines through spontaneous decarboxylation of the intermediate adduct. Forcing the decarboxylation in some cases generated a vinyl group by decarboxylative elimination of the phthalimido group.
Oxidative damage of proline residues by nitrate radicals (NO3): A kinetic and product study
Nathanael, Joses G.,Nuske, Madison R.,Richter, Annika,White, Jonathan M.,Wille, Uta
, p. 6949 - 6957 (2020/10/02)
Tertiary amides, such as in N-acylated proline or N-methyl glycine residues, react rapidly with nitrate radicals (NO3) with absolute rate coefficients in the range of 4-7 × 108 M-1 s-1 in acetonitrile. The major pathway proceeds through oxidative electron transfer (ET) at nitrogen, whereas hydrogen abstraction is only a minor contributor under these conditions. However, steric hindrance at the amide, for example by alkyl side chains at the α-carbon, lowers the rate coefficient by up to 75%, indicating that NO3-induced oxidation of amide bonds proceeds through initial formation of a charge transfer complex. Furthermore, the rate of oxidative damage of proline and N-methyl glycine is significantly influenced by its position in a peptide. Thus, neighbouring peptide bonds, particularly in the N-direction, reduce the electron density at the tertiary amide, which slows down the rate of ET by up to one order of magnitude. The results from these model studies suggest that the susceptibility of proline residues in peptides to radical-induced oxidative damage should be considerably reduced, compared with the single amino acid.
Organocatalyzed Aerobic Oxidation of Aldehydes to Acids
Dai, Peng-Fei,Qu, Jian-Ping,Kang, Yan-Biao
supporting information, p. 1393 - 1396 (2019/02/26)
The first example organocatalyzed aerobic oxidation of aldehydes to carboxylic acids in both organic solvent and water under mild conditions is developed. As low as 5 mol % N-hydroxyphthalimide was used as the organocatalyst, and molecular O2 was used as the sole oxidant. No transition metals or hazardous oxidants or cocatalysts were involved. A wide range of carboxylic acids bearing diverse functional groups were obtained from aldehydes, even from alcohols, in high yields.
Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
supporting information, p. 14365 - 14373 (2019/09/06)
The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
Synthesis, anti-mycobacterial and cytotoxic evaluation of substituted isoindoline-1,3-dione-4-aminoquinolines coupled: Via alkyl/amide linkers
Rani, Anu,Viljoen, Albertus,Johansen, Matt D.,Kremer, Laurent,Kumar, Vipan
supporting information, p. 8515 - 8528 (2019/03/21)
A series of secondary amine-substituted isoindoline-1,3-dione-4-aminoquinolines were prepared via microwave heating and assayed for their anti-mycobacterial activities. The compound with a butyl chain as a spacer between the two pharmacophores and piperidine as the secondary amine component on the isoindoline ring was the most potent and non-cytotoxic among the synthesized compounds, exhibiting a minimum inhibitory concentration (MIC99) of 6.25 μg mL-1 against Mycobacterium tuberculosis.
Substituted 1,3-dioxoisoindoline-4-aminoquinolines coupled via amide linkers: Synthesis, antiplasmodial and cytotoxic evaluation
Rani, Anu,Legac, Jenny,Rosenthal, Philip J.,Kumar, Vipan
, (2019/04/17)
Synthesis of C-5-substituted 1,3-dioxoisoindoline-4-aminoquinolines having amide group as a spacer was developed with an intent to evaluate their antiplasmodial activities. The synthesized dioxoisoindoline-aminoquinolines tethered with β-alanine as a spacer and secondary amine as substituent displayed good anti-plasmodial activities. Compound 7j, with an optimum combination of β-alanine and an ethyl chain length as linker along with diethylamine as the secondary amine counterpart at dioxoisoindoline proved to be most potent and non-cytotoxic with IC50 of 0.097 μM against W2 strain of P. falciparum and a selective index of >2000.
Regioselective β-Csp3-Arylation of β-Alanine: An Approach for the Exclusive Synthesis of Diverse β-Aryl-β-amino Acids
Chowdhury, Sushobhan,Vaishnav, Roopal,Panwar, Namita,Haq, Wahajul
, p. 2512 - 2522 (2019/03/07)
An approach for the synthesis of a variety of new β-aryl-β-amino acids has been developed via a palladium-catalyzed auxiliary-directed regioselective Csp3-H arylation of the unactivated β-methylene bond of β-alanine. The use of 8-aminoquinoline amide as an auxiliary efficiently directs the desired regioselective β-Csp3-H functionalization. The developed protocol enables the easy and straightforward access to several high-value β-aryl-β-amino acids useful for peptide engineering, starting from inexpensive and readily available β-alanine precursors in moderate to excellent yields.
