scholarly journals Synthesis of Mono- and Dithiols of Tetraethylene Glycol and Poly(ethylene glycol)s via Enzyme Catalysis

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 228 ◽  
Author(s):  
Prajakatta Mulay ◽  
Gayatri Shrikhande ◽  
Judit Puskas
Keyword(s):  
Nmr Spectroscopy ◽  
Ethylene Glycol ◽  
1H Nmr ◽  
Enzyme Catalysis ◽  
1H Nmr Spectroscopy ◽  
13C Nmr Spectroscopy ◽  
Tetraethylene Glycol ◽  
Candida Antarctica Lipase ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

This paper investigates the transesterification of methyl 3-mercaptopropionate (MP-SH) with tetraethylene glycol (TEG) and poly(ethylene glycol)s (PEG)s catalyzed by Candida antarctica Lipase B (CALB) without the use of solvent (in bulk). The progress of the reactions was monitored by 1H-NMR spectroscopy. We found that the reactions proceeded in a step-wise manner, first producing monothiols. TEG-monothiol was obtained in 15 min, while conversion to dithiol took 8 h. Monothiols from PEGs with Mn = 1000 and 2050 g/mol were obtained in 8 and 16 h, respectively. MALDI-ToF mass spectrometry verified the absence of dithiols. The synthesis of dithiols required additional fresh CALB and MP-SH. The structure of the products was confirmed by 1H-NMR and 13C-NMR spectroscopy. Enzyme catalysis was found to be a powerful tool to effectively synthesize thiol-functionalized TEGs and PEGs.

scholarly journals Secondary metabolites of three endemic Centaurea L. species

2014 ◽  
Vol 79 (11) ◽  
pp. 1355-1362 ◽  
Author(s):  
Vele Tesevic ◽  
Ivana Aljancic ◽  
Slobodan Milosavljevic ◽  
Vlatka Vajs ◽  
Iris Djordjevic ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Nmr Spectroscopy ◽  
Secondary Metabolites ◽  
Sesquiterpene Lactone ◽  
1H Nmr ◽  
13C Nmr ◽  
1H Nmr Spectroscopy ◽  
13C Nmr Spectroscopy ◽  
Esi Ms ◽  
Aerial Parts

The aerial parts of three endemic Centaurea L. species, namely C. tomorosii Micevski, C. soskae Hayek and C. galicicae Micevski, afforded sesquiterpene lactone cnicin (1) and seven flavonoids: apigenin (2), isokaempferide (3), hispidulin (4), eupatorin (5), cirsimaritin (6), santaflavone (7) and salvigenin (8). The structures of the isolated compounds were determined by UV, 1H NMR and 13C NMR spectroscopy and HR-ESI-MS spectrometry. 1H NMR spectroscopy was used as a method for quantitative analysis of sesquiterpene lactone cnicin.

Fluorescence Microscopy Study of Protein Adsorption at Modified Glassy Carbon Surfaces

2005 ◽  
Vol 58 (4) ◽  
pp. 275 ◽  
Author(s):  
Alison J. Downard ◽  
Sandra L. Jackson ◽  
Emelyn S. Q. Tan
Keyword(s):  
Fluorescence Microscopy ◽  
Ethylene Glycol ◽  
Protein Adsorption ◽  
Glassy Carbon ◽  
Direct Method ◽  
Primary Amines ◽  
Tetraethylene Glycol ◽  
Surface Films ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

Glassy carbon (GC) surfaces were modified with thin films by means of electrochemically assisted reduction of aryl diazonium salts and oxidation of primary amines. GC plates with modified and unmodified areas were exposed to solutions of fluorescently labelled bovine serum albumin (BSA-FITC). Fluorescence microscopy was found to be a simple and direct method for comparing adsorption of BSA-FITC between the different areas. Modification with methylbenzene, hexylbenzene, poly(ethylene glycol) benzene, and tetraethylene glycol diamine groups increases protein adsorption relative to unmodified GC. Hexylamine and the poly(ethylene glycol) diamine ED-2003 reduce protein adsorption. The results give insight into some factors controlling protein adsorption at these surface films.

scholarly journals Polymer Networks Synthesized from Poly(Sorbitol Adipate) and Functionalized Poly(Ethylene Glycol)

Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 22
Author(s):  
Haroon Rashid ◽  
Yury Golitsyn ◽  
Muhammad Humayun Bilal ◽  
Karsten Mäder ◽  
Detlef Reichert ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Ethylene Glycol ◽  
Polymer Networks ◽  
Coupling Constants ◽  
Cross Linking ◽  
Magic Angle ◽  
Poly Ethylene Glycol ◽  
Component Structure ◽  
Degree Of Swelling ◽  
Poly Ethylene

Polymer networks were prepared by Steglich esterification using poly(sorbitol adipate) (PSA) and poly(sorbitol adipate)-graft-poly(ethylene glycol) mono methyl ether (PSA-g-mPEG12) copolymer. Utilizing multi-hydroxyl functionalities of PSA, poly(ethylene glycol) (PEG) was first grafted onto a PSA backbone. Then the cross-linking of PSA or PSA-g-mPEG12 was carried out with disuccinyl PEG of different molar masses (Suc-PEGn-Suc). Polymers were characterized through nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). The degree of swelling of networks was investigated through water (D2O) uptake studies, while for detailed examination of their structural dynamics, networks were studied using 13C magic angle spinning NMR (13C MAS NMR) spectroscopy, 1H double quantum NMR (1H DQ NMR) spectroscopy, and 1H pulsed field gradient NMR (1H PFG NMR) spectroscopy. These solid state NMR results revealed that the networks were composed of a two component structure, having different dipolar coupling constants. The diffusion of solvent molecules depended on the degree of swelling that was imparted to the network by the varying chain length of the PEG based cross-linking agent.

NMR Spectroscopy Reveals Cytochromec–Poly(ethylene glycol) Interactions

ChemBioChem ◽  
2008 ◽  
Vol 9 (5) ◽  
pp. 685-688 ◽  
Author(s):  
Peter B. Crowley ◽  
Keith Brett ◽  
Jimmy Muldoon
Keyword(s):  
Nmr Spectroscopy ◽  
Ethylene Glycol ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene
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