Photochemistry of N-nitroso-N-alkyl amino acids: a facile oxidative decarboxylation

1980 ◽  
Vol 58 (23) ◽  
pp. 2477-2483 ◽  
Author(s):  
Yuan L. Chow ◽  
Douglas P. Horning ◽  
Joël Polo
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Amino Acid ◽  
Carboxyl Groups ◽  
Oxidative Decarboxylation ◽  
Solid States ◽  
Intramolecular Association

Several N-alkyl or N-phenyl-N-nitroso α-amino acids were synthesized and were shown to photolytically rearrange to amidoximes with concurrent decarboxylation in solution or solid states without the presence of externally added acids. In contrast, N-nitrosonipecotinic acid, a N-nitroso β-amino acid, as well as N-nitrosopiperidine in the presence of acetic acid were not photolabile. The photolability of N-nitroso α-amino acids was ascribed to the presence of an intramolecular association between the nitrosamino and carboxyl groups through hydrogen bonding. The species having the hydrogen bonding through the nitroso oxygen in the Z-configuration was believed to be photolabile and decomposed to alkylideneimines as the primary product. The mechanism of the oxidative photorearrangement was discussed.

X-ray studies on crystalline complexes involving amino acids and peptides. XL. Conformational variability, recurring and new features of aggregation, and effect of chirality in the malonic acid complexes of DL- and L-arginine

2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Crystal Structures ◽  
Malonic Acid ◽  
Conformational Flexibility ◽  
X Ray ◽  
Conformational Variability ◽  
Aggregation Pattern ◽  
Positively Charged

The crystal structures of the complexes of malonic acid with DL- and L-arginine, which contain positively charged argininium ions and negatively charged semimalonate ions, further demonstrate the conformational flexibility of amino acids. A larger proportion of folded conformations than would be expected on the basis of steric consideration appears to occur in arginine, presumably because of the requirements of hydrogen bonding. The aggregation pattern in the DL-arginine complex bears varying degrees of resemblance to patterns observed in other similar structures. An antiparallel hydrogen-bonded dimeric arrangement of arginine, and to a lesser extent lysine, is a recurring motif. Similarities also exist among the structures in the interactions with this motif and its assembly into larger features of aggregation. However, the aggregation pattern observed in the L-arginine complex differs from any observed so far, which demonstrates that all the general patterns of amino-acid aggregation have not yet been elucidated. The two complexes represent cases where the reversal of the chirality of half the amino-acid molecules leads to a fundamentally different aggregation pattern.

Amino acid mediated mesopore formation in LTA zeolites

2016 ◽  
Vol 4 (6) ◽  
pp. 2305-2313 ◽  
Author(s):  
Zhuwen Chen ◽  
Jian Zhang ◽  
Bole Yu ◽  
Guangchao Zheng ◽  
Jing Zhao ◽  
...  
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Mesoporous Zeolites ◽  
Calcination Step ◽  
Self Assembled

Amino acids, self-assembledin situ viahydrogen bonding, have been used to synthesize mesoporous zeolites without a calcination step.

Gabapentin Markedly Reduces Acetic Acid–induced Visceral Nociception

2003 ◽  
Vol 98 (3) ◽  
pp. 729-733 ◽  
Author(s):  
Yi Feng ◽  
Minglei Cui ◽  
William D. Willis
Keyword(s):  
Amino Acids ◽  
Spinal Cord ◽  
Acetic Acid ◽  
Amino Acid ◽  
Intraperitoneal Injection ◽  
Visceral Pain ◽  
Antinociceptive Effect ◽  
Intraperitoneal Administration ◽  
Amino Acid Release ◽  
Acid Release

Background Gabapentin has recently been used clinically as an antihyperalgesic agent to treat certain neuropathic pain states. The aim of this study is to test whether gabapentin is able to inhibit responses to peritoneal irritation-induced visceral pain and to examine the effect of gabapentin on spinal cord amino acid release. Methods The acetic acid-induced writhing assay was used in rats to determine the degree of antinociception. The rats received an intraperitoneal injection of acetic acid 40 min after intraperitoneal administration of vehicle or gabapentin (50, 100, or 200 mg/kg). Cerebrospinal fluid dialysate was collected by microdialysis from the spinal subarachnoid space in anesthetized rats. Acetic acid-induced release of amino acids into the dialysate, including glutamate, aspartate, serine, glutamine, and glycine, following intraperitoneal injection of acetic acid was evaluated by measurements of changes in the concentrations of these amino acids. The effects of pretreatment with saline or gabapentin (100 mg/kg intraperitoneal) on amino acid release were compared. Results Gabapentin reduced writhing responses in a dose-related fashion. Dialysate concentrations of glutamate, aspartate, and serine increased significantly following intraperitoneal injection of acetic acid, while glutamine and glycine concentrations were not increased significantly. When compared to saline-treated rats, animals pretreated with 100 mg/kg gabapentin showed suppression of the acetic acid-induced increases in glutamate, aspartate, and serine concentrations. Conclusions These data demonstrate that gabapentin effectively inhibits acetic acid-induced nociception, and the antinociceptive effect of gabapentin correlates with the suppression of noxious-evoked release of excitatory amino acids in the spinal cord.

scholarly journals The titration of amino- and carboxyl-groups in amino-acids, polypeptides, etc. parts IV-VI.— Estimations in presence of formol and alcohol

1924 ◽  
Vol 95 (671) ◽  
pp. 500-522 ◽  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Carboxyl Groups ◽  
Titration Method ◽  
Basic Character

In the well-known formol titration method of Sörensen (22), neutralised formaldehyde is added to the solution of the amino-acid (or other compound containing —NH 2 ) and standard alkali run in until the production of a red colour with penolphthalein. An explanation of this method that has often been advanced in text-books and elsewhere is that the original amino-acid is neutral because the basic—NH 2 neutralises the acidic —CO 2 H, and that with the addition of formalde-hyde the basic character of the —NH 2 is destroyed, with the result that the acidic —CO 2 H is free to be titrated.

Synthesis, Characterization and Crystal Structure of [Tetra-μ3-iodotetrakis{1'-(diphenylphosphino)ferrocenecarboxylic Acid-P}tetracopper(I)]-Acetic Acid (1 : 2)

1998 ◽  
Vol 63 (1) ◽  
pp. 64-74 ◽  
Author(s):  
Petr Štěpnička ◽  
Róbert Gyepes ◽  
Jaroslav Podlaha
Keyword(s):  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Carboxyl Groups ◽  
Mutual Arrangement ◽  
Intermolecular Hydrogen Bonding ◽  
Tetrahedral Coordination ◽  
The Core ◽  
Conformation Changes ◽  
Tetrameric Structure ◽  
Ferrocenecarboxylic Acid

The title compound was prepared by the reaction of 1'-(diphenylphosphino)ferrocenecarboxylic acid with copper(I) iodide in acetic acid. It has the tetrameric structure of the heterocubane type and all four monomeric units are crystallographically independent. The central Cu4I4 core is severely distorted from the Oh symmetry as a consequence of disparate radii of the atoms; however, this does not lead to transformation of the core into a stepped arrangement, the feature otherwise common for similar tetrameric structures. The ligand behaves as a monodentate phosphine and completes the approximately tetrahedral coordination polyhedron around copper(I). The carboxyl groups remain undissociated and uncoordinated but participate in intermolecular hydrogen bonding. Two carboxyl groups link the molecules of the tetramer into a zig-zag chain; the remaining two are bonded to molecules of solvating acetic acid which act as spacers between the chains. As expected, the geometry of the flexible ligand is remarkably influenced by the hydrogen bonding, the main conformation changes taking place at the P-C bonds and in the mutual arrangement of the cyclopentadienyl rings.

scholarly journals The Effects of Dietary Glycine on the Acetic Acid-Induced Mouse Model of Colitis

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Xin Wu ◽  
Yongmin Zheng ◽  
Jie Ma ◽  
Jie Yin ◽  
Shuai Chen
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Acetic Acid ◽  
Amino Acid ◽  
Mouse Model ◽  
Intestinal Microbiota ◽  
Intestinal Inflammation ◽  
Serum Concentrations ◽  
Intestinal Immunity ◽  
Chronic Intestinal Inflammation

Inflammatory bowel disease, a gut disease that is prevalent worldwide, is characterized by chronic intestinal inflammation, such as colitis, and disorder of the gut microbiome. Glycine (Gly) is the simplest amino acid and functions as an anti-inflammatory immune-nutrient and intestinal microbiota regulator. This study aimed at investigating the effect of Gly on colitis induced in mice by intrarectal administration of 5% acetic acid (AA). Bodyweight and survival rates were monitored, and colonic length and weight, serum amino acid concentrations, intestinal inflammation-related gene expression, and colonic microbiota abundances were analyzed. The results showed that Gly dietary supplementation had no effect on the survival rate or the ratio of colonic length to weight. However, Gly supplementation reversed the AA-induced increase in serum concentrations of amino acids such as glutamate, leucine, isoleucine, and valine. Furthermore, Gly inhibited colonic gene expression of interleukin- (IL-) 1β and promoted IL-10 expression in colitis mice. Gly supplementation also reversed the AA-induced reduction in the abundance of bacteria such as Clostridia, Ruminococcaceae, and Clostridiales. This change in the intestinal microbiota was possibly attributable to the changes in colonic IL-10 expression and serum concentrations of valine and leucine. In sum, Gly supplementation regulated the serum concentrations of amino acids, the levels of colonic immune-associated gene expression, and the intestinal microbiota in a mouse model of colitis. These findings enhance our understanding of the role of Gly in regulating metabolism, intestinal immunity, and the gut microbiota in animals afflicted with colitis.

Comparative acidic cleavage experiments with methyl-substituted benzyl esters of amino acids

1967 ◽  
Vol 20 (10) ◽  
pp. 2243 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Amino Acid ◽  
Solid Phase ◽  
Hydrogen Bromide ◽  
Solid Phase Peptide Synthesis ◽  
Amino Acid Derivatives ◽  
Methyl Substitution ◽  
Benzyl Esters ◽  
Layer Chromatography

The action of trifluoroacetic acid and hydrogen bromide in acetic acid, respectively, on the benzyl, p-methylbenzyl, 2,4,6-trimethylbenzyl, and penta-methylbenzyl esters of some amino acid derivatives has been investigated by thin-layer chromatography. Methyl substitution greatly enhances the lability of the ester groups. The possible bearing of the results on solid-phase peptide synthesis is discussed.

scholarly journals Isovaline monohydrate

2013 ◽  
Vol 69 (12) ◽  
pp. o1829-o1830 ◽  
Author(s):  
Ray J. Butcher ◽  
Greg Brewer ◽  
Aaron S. Burton ◽  
Jason P. Dworkin
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Three Dimensional ◽  
Living Systems ◽  
Intermolecular Hydrogen Bonding ◽  
Compound C ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Natural Amino Acids

The title compound, C5H11NO2·H2O, is an isomer of the α-amino acid valine that crystallizes from water in its zwitterion form as a monohydrate. It is not one of the 20 proteinogenic amino acids that are used in living systems and differs from the natural amino acids in that it has no α-H atom. The compound exhibits hydrogen bonding between the water molecule and the carboxylate O atoms and an amine H atom. In addition, there are intermolecular hydrogen-bonding interactions between the carboxylate O atoms and amine H atoms. In the crystal, these extensive N—H...O and O—H...O hydrogen bonds lead to the formation of a three-dimensional network.

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