Carbon-13 Nuclear Magnetic Resonance Studies of Compounds of the Vitamin B6 Group and Related Pyridine Derivatives

1975 ◽  
Vol 53 (16) ◽  
pp. 2406-2412 ◽  
Author(s):  
Roy D. Lapper ◽  
Henry H. Mantsch ◽  
Ian C. P. Smith
Keyword(s):  
Vitamin B6 ◽  
Pyridoxal Phosphate ◽  
Chemical Shifts ◽  
Resonance Assignments ◽  
Low Ph ◽  
Vitamin B ◽  
Pyridine Derivatives ◽  
High Ph ◽  
Methylene Groups ◽  
Predicted Values

The I3C chemical shifts and 13C–31P spin–spin couplings (where applicable) are reported for pyridoxine, pyridoxamine, pyridoxal, pyridoxamine phosphate, and pyridoxal phosphate. Resonance assignments are made by consideration of substituent chemical shift effects, as tested on an analogous series of pyridine derivatives. Increased shielding of the C4′ and C5′ methylene groups of the vitamin B6 compounds and the methyl groups of 3,4-dimethylpyridine relative to the predicted values are attributed to steric compression. In aqueous solution pyridoxal exists as the hemiacetal form, although at high pH it is in rapid equilibrium with a significant amount of the aldehyde form. Pyridoxal phosphate exists as the aldehyde at high pH, as the hydrated aldehyde at low pH, and in a slow equilibrium between detectable amounts of both species at pH 4. The 13C–31P couplings through two bonds lie in the range 4.5 ± 0.5 Hz found for a variety of other organic phosphates. The couplings through three bonds indicate a preference for a trans arrangement of the phosphorus and ring carbon-5.

scholarly journals NMR analysis of 2-(2’,3’-dihydro-1’H-inden-1’-yl)-1H-indene

2001 ◽  
Vol 66 (11-12) ◽  
pp. 753-763 ◽  
Author(s):  
Jovan Jovanovic ◽  
Michael Spiteller ◽  
Peter Spiteller
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Resonance Assignments ◽  
Nmr Resonance Assignments ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Nmr Analysis ◽  
Structural Element ◽  
Nmr Parameters ◽  
Methylene Groups

1H, 13Cand two dimensional NMR analyses were applied to determine the NMR parameters of 2-(2?,3?-dihydro-1?H-inden-1?-yl)-1H-indene. The chemical shifts of all the H- and C-atoms, as well as the appropriate coupling constants were determined and the complete NMR resonance assignments of the molecule are given. The predicted patterns of the four different H atoms of the two methylene groups of the indane structural element coincided completely with the complex patterns in the NMR spectra.

Iminiumsalz-Strukturen bei der durch Pyridoxalphosphat (Vitamin B6) katalysierten Bildung von Aromastoffen und Fehlaromen im Wein

2018 ◽  
Vol 73 (7) ◽  
pp. 521-533 ◽  
Author(s):  
Nikolaus Müller
Keyword(s):  
Vitamin B6 ◽  
Pyridoxal Phosphate ◽  
Acid Metabolism ◽  
Aroma Compounds ◽  
Vitamin B ◽  
Reaction Intermediates ◽  
Wine Production ◽  
Iminium Salt ◽  
Different Types ◽  
Sulfur Containing

Abstract Enzymes that use pyridoxal phosphate (PLP, Vitamin B6) as cofactor constitute a ubiquitous class of biocatalysts. A variety of PLP-dependant enzymes mainly involved in biochemical pathways concerning amino acid metabolism are found in all forms of life. These enzymes also play an important role in wine production, as well in grape growing as in enological processes. The formation of pleasant aroma compounds often runs with participation of pyridoxal-dependant enzymes. But these are also brought into context with the formation of off-odors, especially from sulfur compounds (i.e. sulfur containing amino acids cysteine, methionine). The versatility of PLP-dependant bioreactions arises from its ability to covalently bind the substrate and then to function as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates, containing iminium salt structures. This article summarizes the influence of PLP on sensorically important aroma compounds in wine growing and wine processing.

Tryptophan metabolism and vitamin B6 nutritional status in patients with schistosomiasis mansoni and in infected mice

Parasitology ◽  
1992 ◽  
Vol 104 (3) ◽  
pp. 433-441 ◽  
Author(s):  
E. N. M. Njagi ◽  
D. A. Bender ◽  
G. B. A. Okelo
Keyword(s):  
Vitamin B6 ◽  
Pyridoxal Phosphate ◽  
Reference Range ◽  
Plasma Concentrations ◽  
Test Dose ◽  
Tryptophan Metabolism ◽  
Vitamin B ◽  
Abnormal Response ◽  
Hydroxyindoleacetic Acid ◽  
Activation Coefficient

Patients infected with Schistosoma mansoni showed an abnormal response to a test dose of tryptophan, with little increase in the urinary excretion of kynurenine, hydroxykynurenine, xanthurenic and kynurenic acids, N1-methyl nicotinamide, methyl pyridone carboxamide, 5-hydroxytryptamine or 5-hydroxyindoleacetic acid. In contrast to previous reports, this is different from the pattern of tryptophan metabolism seen in vitamin B6 deficiency. Furthermore, the patients' plasma concentrations of pyridoxal phosphate were within the reference range, and supplementation for 5 days with 20 mg vitamin B6/day did not affect tryptophan metabolism. Treatment with a single dose of Praziquantel resulted in a substantial restoration of normal tryptophan metabolism. In mice infected with S. mansoni there was a similar impairment of tryptophan metabolism, as shown by considerably reduced formation of 14CO2 after the administration of a tracer dose of [14C]tryptophan. Again, the administration of vitamin B6 supplements did not correct tryptophan metabolism in the mice. Treatment with Praziquantel resulted in substantial restoration of the production of 14CO2 from [14C]tryptophan. There was no evidence of vitamin B6 deficiency (as determined by erythrocyte aspartate aminotransferase activation coefficient) associated with infection in the mice, although there was a redistribution of pyridoxal phosphate between tissues, with a reduction in the concentration of liver, spleen and kidney, and an increase in skeletal muscle.

Synthesis and characterization of a series of 1-methyl-4-[2-aryl-1-diazenyl]piperazines and a series of ethyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates

2004 ◽  
Vol 82 (8) ◽  
pp. 1294-1303 ◽  
Author(s):  
Vanessa Renée Little ◽  
Keith Vaughan
Keyword(s):  
Free Energy ◽  
Chemical Shifts ◽  
Linear Free Energy Relationship ◽  
Piperazine Ring ◽  
Linear Free Energy ◽  
In Series ◽  
Methylene Groups ◽  
Diazonium Coupling ◽  
The Difference

1-Methylpiperazine was coupled with a series of diazonium salts to afford the 1-methyl-4-[2-aryl-1-diazenyl]piperazines (2), a new series of triazenes, which have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analysis. Assignment of the chemical shifts to specific protons and carbons in the piperazine ring was facilitated by comparison with the chemical shifts in the model compounds piperazine and 1-methylpiperazine and by a HETCOR experiment with the p-tolyl derivative (2i). A DEPT experiment with 1-methylpiperazine (6) was necessary to distinguish the methyl and methylene groups in 6, and a HETCOR spectrum of 6 enabled the correlation of proton and carbon chemical shifts. Line broadening of the signals from the ring methylene protons is attributed to restricted rotation around the N2-N3 bond of the triazene moiety in 2. The second series of triazenes, the ethyl 4-[2-phenyl-1-diazenyl]-1-piperazinecarboxylates (3), have been prepared by similar diazonium coupling to ethyl 1-piperazinecarboxylate and were similarly characterized. The chemical shifts of the piperazine ring protons are much closer together in series 3 than in series 2, resulting in distortion of the multiplets for these methylenes. It was noticed that the difference between these chemical shifts in 3 exhibited a linear free energy relationship with the Hammett substituent constants for the substituents in the aryl ring. Key words: triazene, piperazine, diazonium coupling, NMR, HETCOR, linear free energy relationship.

scholarly journals The Affinity of Carboplatin to B-Vitamins and Nucleobases

2021 ◽  
Vol 22 (7) ◽  
pp. 3634
Author(s):  
Beata Szefler ◽  
Przemysław Czeleń ◽  
Przemysław Krawczyk
Keyword(s):  
Vitamin B6 ◽  
Pyridoxal Phosphate ◽  
Antitumor Agents ◽  
Lone Pair ◽  
Chemical Compounds ◽  
Free Energies ◽  
Aromatic Rings ◽  
Anti Cancer ◽  
Potential Impact ◽  
Reactive Molecule

Platinum compounds have found wide application in the treatment of various types of cancer and carboplatin is one of the main platinum-based drugs used as antitumor agents. The anticancer activity of carboplatin arises from interacting with DNA and inducing programmed cell death. However, such interactions may occur with other chemical compounds, such as vitamins containing aromatic rings with lone-pair orbitals, which reduces the anti-cancer effect of carboplatin. The most important aspect of the conducted research was related to the evaluation of carboplatin affinity to vitamins from the B group and the potential impact of such interactions on the reduction of therapeutic capabilities of carboplatin in anticancer therapy. Realized computations, including estimation of Gibbs Free Energies, allowed for the identification of the most reactive molecule, namely vitamin B6 (pyridoxal phosphate). In this case, the computational estimations indicating carboplatin reactivity were confirmed by spectrophotometric measurements.

Expression patterns of two carbonic anhydrase genes, Na+/K+-ATPase and V-type H+-ATPase, in the freshwater crayfish, Cherax quadricarinatus, exposed to low pH and high pH

2017 ◽  
Vol 65 (1) ◽  
pp. 50 ◽  
Author(s):  
Muhammad Yousuf Ali ◽  
Ana Pavasovic ◽  
Peter B. Mather ◽  
Peter J. Prentis
Keyword(s):  
Carbonic Anhydrase ◽  
Expression Patterns ◽  
Maximum Level ◽  
Low Ph ◽  
Freshwater Crayfish ◽  
Α Subunit ◽  
Cherax Quadricarinatus ◽  
High Ph ◽  
Internal Ph ◽  
Ph Conditions

Carbonic anhydrase (CA), Na+/K+-ATPase (NKA) and Vacuolar-type H+-ATPase (HAT) play vital roles in osmoregulation and pH balance in decapod crustaceans. As variable pH levels have a significant impact on the physiology of crustaceans, it is crucial to understand the mechanisms by which an animal maintains its internal pH. We examined expression patterns of cytoplasmic (CAc) and membrane-associated form (CAg) of CA, NKA α subunit and HAT subunit a in gills of freshwater crayfish, Cherax quadricarinatus, at three pH levels – 6.2, 7.2 (control) and 8.2 – over 24 h. Expression levels of CAc were significantly increased at low pH and decreased at high pH conditions 24 h after transfer. Expression increased at low pH after 12 h, and reached its maximum level by 24 h. CAg showed a significant increase in expression at 6 h after transfer at low pH. Expression of NKA significantly increased at 6 h after transfer to pH 6.2 and remained elevated for up to 24 h. Expression for HAT and NKA showed similar patterns, where expression significantly increased 6 h after transfer to low pH and remained significantly elevated throughout the experiment. Overall, CAc, CAg, NKA and HAT gene expression is induced at low pH conditions in freshwater crayfish.

Multinuclear NMR spectra of [Pt(L)Cl3]− (L = pyridine derivatives) complexes and crystal structure of trans-Pt(2,6-di(hydroxymethyl)pyridine)2Cl2•2H2O

1996 ◽  
Vol 74 (11) ◽  
pp. 2121-2130 ◽  
Author(s):  
Fernande D. , ◽  
Corinne Bensimon ◽  
André L. Beauchamp
Keyword(s):  
Crystal Structure ◽  
Pyridine Ring ◽  
Chemical Shifts ◽  
Bond Distance ◽  
Coupling Constants ◽  
Mirror Plane ◽  
Pyridine Derivative ◽  
Pyridine Derivatives ◽  
Pyridine Ligand ◽  
Twofold Axis

Complexes of the type [Pt(L)Cl3]− (L = pyridine derivative) were synthesized and studied by 13C and 195Pt NMR spectroscopies. The 195Pt signals were observed between −1720 and −1897 ppm. No correlation between the δ(Pt) and the pKa of the protonated pyridine derivatives was found. The chemical shifts vary with the substituents on the pyridine ligand. Compounds with substituents in ortho positions were observed at lower fields, except for complexes containing hydroxy or amine groups. The latter compounds were observed at higher fields, close to the signals of the Pt-unsubstituted pyridine compound. These results were explained in terms of the solvent effect. The chemical shifts δ(C) and the coupling constants J(13C–195Pt) were measured and the results interpreted with a view of obtaining information on the nature of the Pt—N bond. The possibility of π-bonding between platinum and the pyridine ligand is examined. The conformation of the pyridine ring in relation to the platinum plane and the energies of the rotation barriers around the Pt—N bond in these types of platinum(II) complexes are briefly discussed. The crystal structure of trans-Pt(2,6-(HOCH2)2py)2Cl2•2H2O was determined by X-ray diffraction. The compound is monoclinic, C2/m, a = 7.022(6), b = 15.646(13), c = 8.344(10) Å, β = 93.35(8)°, Z = 2, R = 0.037. The platinum atom is located at the junction of the twofold axis and the mirror plane, the N atoms and the para-C atom of the pyridine ring are situated on the twofold axis, and the chloride ligands are on the mirror plane. The compound crystallizes with molecules of water, which are H-bonded to the hydroxy groups. The Pt—Cl bond distance is 2.306(2) Å, and that of the Pt—N bond is 2.041 (6) Å. The dihedral angle between the platinum and the pyridine planes is 79.8°. Key words: platinum, pyridine derivatives, NMR, crystal structure.

COMMITTEE ON NUTRITION

PEDIATRICS ◽  
1966 ◽  
Vol 38 (6) ◽  
pp. 1068-1076
Author(s):  
Keyword(s):  
Vitamin B6 ◽  
Pyridoxal Phosphate ◽  
Normal Population ◽  
Clinical Signs ◽  
Normal Activity ◽  
Limited Information ◽  
Adequate Intake ◽  
Time Data ◽  
Binding Properties ◽  
Adequate Diet

Because of the limited information available it is not possible to derive precise figures for daily requirements of vitamin B6 in infants and children at this time. Data currently available suggest that the daily need in childhood is 0.5 to 1.5 mg and in adolescence is 1.5 to 2 mg. The requirement in infancy is clearly related to protein intake and is 20µg/gm of dietary protein. Requirements of a few individuals will undoubtedly be higher than the estimates for the normal population. Some of these patients will manifest frank biochemical and clinical signs of deficiency which will usually be promptly reversed by administration of small additional amounts of pyridoxine. Another group of patients will require large amounts of the vitamin to balance the heritable alteration in binding properties of a specific apoenzyme requiring pyridoxal phosphate for normal activity. It would appear that most infants, children and adults will have little difficulty in achieving an adequate intake of vitamin B6 if they receive what is considered to be in other respects an adequate diet.

Roth-like Spot in an Adult With Vitamin B6 Deficiency and Nonepileptic Seizures

2021 ◽  
pp. 247412642110287
Author(s):  
Diana Driscoll ◽  
David Callanan
Keyword(s):  
Differential Diagnosis ◽  
Adult Patient ◽  
Vitamin B6 ◽  
Vitamin B ◽  
Case Review ◽  
Single Patient ◽  
Retinal Lesion ◽  
History Of ◽  
Nonepileptic Seizures ◽  
Vitamin B6 Deficiency

Purpose: This work reports retinal findings in an adult patient with vitamin B6 deficiency. Methods: A case review of a single patient is presented. Results: A patient with a Roth-type retinal lesion and a history of nonepileptic seizures was found to have lymphocytic colitis. She was treated with pyridoxine, which resolved her seizures and the white-centered hemorrhage. Conclusions: Vitamin B6 deficiency should be considered in the differential diagnosis of patients presenting with white-centered hemorrhages and a history of nonepileptic seizures.

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