scholarly journals The use of microfluidic hardware in the synthesis of oligohexamethylene guanidine derivatives

2021 ◽  
Vol 16 (4) ◽  
pp. 307-317
Author(s):  
D. A. Akhmedova ◽  
D. O. Shatalov ◽  
I. S. Ivanov ◽  
A. V. Aydakova ◽  
A. Herbst ◽  
...  
Keyword(s):  
13C Nmr ◽  
Traditional Method ◽  
High Performance ◽  
Hplc Analysis ◽  
13C Nmr Spectroscopy ◽  
Lower Content ◽  
Nmr Spectrum ◽  
Guanidine Derivatives ◽  
Type Reactor ◽  
Flow Type

Objectives. To develop a method for the microfluidic synthesis of oligohexamethylene guanidine salts in a flow-type reactor and to evaluate its effectiveness in relation to the synthesis in a traditional capacitive reactor and compare the purities of products obtained by these methods.Methods. The synthesis of oligohexamethylene guanidine bihydrocarbonate (OHMG-BHC) was done using microfluidic hardware and the classical approach in volume. The purity and structure of the resulting product were confirmed by 13C NMR spectroscopy and high-performance liquid chromatography (HPLC).Results. The 13C NMR spectrum of OHMG-BHC in classical bulk synthesis demonstrates that the product is unbranched and contains additionally unidentifiable impurities, in contrast to the sample obtained by the microfluidic method. Furthermore, the HPLC analysis showed that the OHMG-BHC sample synthesized using microfluidic technology has a 1.5-fold lower content than the initial monomers.Conclusions. The advantage of synthesizing OHMG-BHC in a flow-type reactor compared to the traditional method of synthesis in volume is demonstrated since a product with a higher degree of purity is obtained.

scholarly journals 13C-NMR-Spektroskopie an polycyclischen Aromaten, IV Das 13C-NMR-Spektrum von 1-Aminopyren / 13C NMR Spectroscopy of Polycyclic Aromatics, IV The 13C NMR Spectrum of 1-Aminopyrene

1975 ◽  
Vol 30 (9-10) ◽  
pp. 800-803 ◽  
Author(s):  
Ludger Ernst
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
High Field ◽  
Chemical Shifts ◽  
Double Resonance ◽  
Substituent Effects ◽  
13C Nmr Spectroscopy ◽  
Polycyclic Aromatics ◽  
Nmr Spectrum ◽  
C Nmr

In the 13C NMR spectrum of ] -aminopyrene (1) in [D6] acetone all carbon atoms are anisochronous. Most of the sixteen signals can be safely assigned by selective 13C{1H}double resonance experiments and by the interpretation of proton-coupled 13C as well as with the aid of off-resonance noise-decoupled 13C{1H} spectra. Substituent effects on chemical shifts in rings A, B, and D are compared with those of the 1- and 2-aminonaphthalenes (2, 3). Even in ring C, most distant from the substituent, relatively strong high-field shifts are observed which are ascribed to mesomerism.

Zur Struktur von Hydroxy-5-phenyl-furanonen: Lösungs-NMR, Festkörper-13C-NMR und Röntgenstruktur im Vergleich / On the Structure of Hydroxy-5-phenyl-furanone Derivatives: NMR Spectroscopy in Solution and High Resolution Solid State 13C NMR Spectroscopy in Relation to X-Ray Crystallography

1993 ◽  
Vol 48 (10) ◽  
pp. 1372-1380 ◽  
Author(s):  
M. Schmidt ◽  
K. Albert ◽  
R. Brindle ◽  
C. Maichle-Mössmer ◽  
K. Eger
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Solid State Nmr ◽  
Dehydroascorbic Acid ◽  
13C Nmr Spectroscopy ◽  
Crystal Structure Analysis ◽  
Nmr Spectrum ◽  
X Ray ◽  
X Ray Crystallography

The structure of (5H)-2-Amino-3-hydroxy-5-phenyl-furan-4-one (lb) was determined by NMR-spectroscopy in solution and in the solid state. The structure of its oxidation product, 3,4-Dihydro-3,3,4,4-tetrahydroxy-5-phenyl-furan-2(5H)-one (7), given in the literature as 5-Phenyl-2,3,4-(5H)-furan-trione, was determined by NMR spectroscopy and crystal structure analysis. The solid state NMR spectrum of 7 was compared to the spectrum of dehydroascorbic acid

scholarly journals SYLFATION OF XYLAN WITH SULFAMIC ACID IN N,N-DIMETHYLFORMAMIDE

2017 ◽  
pp. 29-36
Author(s):  
Владимир (Vladimir) Александрович (Aleksandrovich) Левданский (Levdanskii) ◽  
Александр (Aleksandr) Александрович (Aleksandrovich) Кондрасенко (Kondrasenko) ◽  
Александр (Aleksandr) Владимирович (Vladimirovich) Левданский (Levdanskii) ◽  
Борис (Boris) Николаевич (Nikolaevich) Кузнецов (Kuznetsov)
Keyword(s):  
13C Nmr ◽  
Sulfamic Acid ◽  
13C Nmr Spectroscopy ◽  
Partial Substitution ◽  
Hydroxyl Groups ◽  
Absorption Bands ◽  
Nmr Spectrum ◽  
Substitution Degree ◽  
Stretching Vibrations ◽  
First Time

Sulfation of birch wood xylan by sulfamic acid in N,N-dimethylformamide (DMF) in the presence of urea was studied for the first time. The effect of the duration of sulfation of xylan with a mixture of sulfamic acid–urea in DMF on the yield and substitution degree of xylan sulfates was studied. The sulfur content in the obtained samples was determined using chemical method. It was found, that the degree of substitution in the obtained xylan sulfates was in the range from 1.30 to 1.64 at sulfation for 1–2 hours. The structure of initial and sulfated xylan was investigated with the use of FTIR and 13C NMR spectroscopy methods. The introduction of sulfate groups into the structure of xylan was confirmed by appearance in FTIR spectra new absorption bands characteristic for the stretching vibrations n (C–O–S) at 804 cm-1, symmetric stretching vibrations ns (SO2) at 1009 cm-1, asymmetric stretching vibrations nas (SO2) at 1244 and 1260 cm-1.Studying of 13C NMR spectrum of the obtained xylan sulfates showed that there was partial substitution of hydroxyl groups at С2 and С3 positions of anhydroxylose units of xylan.

The Dtermination of Paracetamol by HPLC Validation of the Method and Application on Serum Samples

2018 ◽  
Vol 69 (3) ◽  
pp. 627-631 ◽  
Author(s):  
Viorica Ohriac (Popa) ◽  
Diana Cimpoesu ◽  
Adrian Florin Spac ◽  
Paul Nedelea ◽  
Voichita Lazureanu ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Hplc Analysis ◽  
Emotional Experience ◽  
Optimum Conditions ◽  
Serum Samples ◽  
Liquid Chromatograph ◽  
Mobile Phase Flow Rate ◽  
Quantification Limit

Pain is defined as a disagreeable sensory and emotional experience related to a tissue or potential lesion. Paracetamol (Acetaminophen) is the most used non-morphine analgesic. For the determination of paracetamol we developed and validated the high performance liquid chromatography (HPLC) analysis using a Dionex Ultimate 3000 liquid chromatograph equipped with a multidimensional detector. After determining the optimum conditions of analysis (80/20 water / acetonitrile mobile phase, flow rate 1.0 mL / min, detection wavelength 245 nm) we validated the method following the following parameters: linearity of response function, linearity of results, limit (LD = 0.66 mg / mL) and quantification limit (LQ = 2.00 mg / mL), and precision. The method of determining paracetamol by HPLC was applied to 30 samples of serum collected from patients who had pain and were treated with paracetamol.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

scholarly journals Simple HPLC-PDA Analysis to Determine Illegal Synthetic Dyes in Herbal Medicines

2021 ◽  
Vol 11 (14) ◽  
pp. 6641
Author(s):  
Kyung-Yuk Ko ◽  
Eun-Young Choi ◽  
Se-Hee Jeong ◽  
Sohwa Kim ◽  
Choon-Kil Lee ◽  
...  
Keyword(s):  
High Performance ◽  
Hplc Analysis ◽  
Ammonium Acetate ◽  
Herbal Medicines ◽  
Positive Sample ◽  
Array Detector ◽  
Synthetic Dyes ◽  
Sunset Yellow ◽  
Herbal Medication ◽  
Relative Standard

Various synthetic dyes are artificially added to herbal medicines for the purpose of visual attraction. In order to monitor the illegal usage of synthetic dyes in herbal medication, a rapid and straightforward analysis method to determine synthetic dyes is required. The study aimed to develop and validate a high-performance liquid chromatography (HPLC) analysis to determine ten synthetic dyes in Hawthorn fruit, Cornus fruit, and Schisandra fruit. Ten synthetic dyes such as Tartrazine, Sunset yellow, Metanil yellow, Auramine O, Amaranth, Orange II, Acid red 73, Amaranth, New Coccine, Azorubine, and Erythrosine B, were extracted using 50 mM ammonium acetate in 70% MeOH; then separated by gradient elution with a mobile phase consisting of acetonitrile and 50 mM ammonium acetate in distilled water using a photodiode array detector (PDA) at 428 nm or 500 nm. In addition, this study established the LC-MS/MS method to confirm the existence of synthetic dyes in the positive sample solution. The HPLC analysis had good linearity (r2 > 0.999). The recoveries of this method ranged from 74.6~132.1%, and the relative standard deviation (RSD) values were less than 6.9%. Most of the samples fulfilled the acceptance criteria of the AOAC guideline. This study demonstrates that the HPLC analysis can be applied to determine ten synthetic dyes in herbal medication.

scholarly journals Homopiperazine (Hexahydro-1,4-diazepine)

Molbank ◽  
10.3390/m1200 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1200
Author(s):  
R. Alan Aitken ◽  
Dheirya K. Sonecha ◽  
Alexandra M. Z. Slawin
Keyword(s):  
13C Nmr ◽  
Title Compound ◽  
Coupling Constants ◽  
15N Nmr ◽  
Time Data ◽  
Nmr Spectrum ◽  
X Ray ◽  
First Time

The X-ray structure of the title compound has been determined for the first time. Data on its 1H–13C-NMR coupling constants and 15N-NMR spectrum are also given.

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