Improved understanding of technical lignin functionalization through comprehensive structural characterization of fractionated pine kraft lignins modified by the Mannich reaction

2021 ◽  
Author(s):  
Matthew Kollman ◽  
Xiao Jiang ◽  
Samuel John Thompson ◽  
Ofei D. Mante ◽  
David Dayton ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Mannich Reaction ◽  
Kraft Lignin ◽  
Technical Lignin ◽  
The Mannich Reaction ◽  
Technical Lignins

Amino alkylation of technical lignins via the Mannich reaction can be used as an analytical derivatization technique, but also in an applied manner to improve kraft lignin hydrophilicity or metal...

Structural Characterization of Pine Kraft Lignin: BioChoice Lignin vs Indulin AT

2016 ◽  
Vol 36 (6) ◽  
pp. 432-446 ◽  
Author(s):  
Zhoujian Hu ◽  
Xueyu Du ◽  
Jie Liu ◽  
Hou-min Chang ◽  
Hasan Jameel
Keyword(s):  
Structural Characterization ◽  
Kraft Lignin

Synthesis, Transformations and Characterization of 8 Aminomethyl Substituted Umbelliferones as Probable Anti-Arrhythmic Agents

2019 ◽  
Vol 15 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Alla V. Lipeeva ◽  
Arkady O. Brysgalov ◽  
Tatyana G. Tolstikova ◽  
Elvira E. Shults
Keyword(s):  
Mannich Reaction ◽  
Suzuki Reaction ◽  
Mannich Bases ◽  
Pharmacological Agents ◽  
Natural Coumarin ◽  
The Mannich Reaction ◽  
First Time ◽  
Substituted Coumarins

Background: Coumarin and modified nitrogen heterocyclic nuclei show biological activity. Combining these into a hybrid molecule could lead to new pharmacological agents. A series of hybrid compounds combining coumarin and piperidine, piperazine, purine or tetrahydroisoquinoline moieties were synthesized and evaluated for anti-arrhythmic activity. Methods: The Mannich reaction of coumarins (peurutenicin, peucenol and 6-cyanoumbelliferrone) with formaldehyde and various amines, including several alkaloids – anabasine, theophylline or tetrahydroisoquinolines, proceeds by heating under reflux in dioxane in the presence of 4-dimethylaminopyridine. The Suzuki reaction of 6,8-disubstituted umbelliferone triflate was used for the introduction of an aryl substituent in position 7 of the the coumarin framework. Results: Twenty two novel coumarin-based Mannich bases were synthesized via introduction of functional aminomethyl group at position 8 of 6 substituted 7-hydroxy-2H-chromen-2-ones by Mannich reaction. The results illustrated that the C-6 and C-8 substituents’ effect was obvious in our designed system and there was a relationship between the structures and the anti-arrhythmic activity of the 6,7,8- trisubstituted coumarins. 8-(6,7-dimethoxy-1-(3,4,5-trimethoxyphenyl)-tetrahydroisoquinolinylmethyl)- substituted peucenol derivatives shown in vivo a pronounced and selective anti-arrhythmic activity on epinephrine arrhythmias in comparison with natural coumarin peucenol. The moderate toxicity of the new compound encouraged further design of therapeutically relevant analogues based on this novel type of coumarin- tetrahydroisoquinoline hybrids. Conclusion: We have developed a mild reaction protocol to synthesize new mannich products on the basis of substituted coumarins. The anti-arrhythmic activity of coumarin-tetrahydroisoquinoline hybrids was revealed. We report for the first time that coumarin containing 8-(1-(3,4,5-trimethoxyphenyl) tetrahydroisoquinolinyl)methyl) substituent offer a suitable scaffold for the development of novel anti-arrhythmic agents.

scholarly journals Modified and unmodified technical lignins as flame retardants for polypropylene

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Petri Widsten ◽  
Tarja Tamminen ◽  
Antti Paajanen ◽  
Tuula Hakkarainen ◽  
Tiina Liitiä
Keyword(s):  
Heat Release ◽  
Flame Retardants ◽  
Building Materials ◽  
Kraft Lignin ◽  
Total Heat Release ◽  
Chemically Modified ◽  
Peak Heat Release Rate ◽  
The Mannich Reaction ◽  
Intumescent System ◽  
Technical Lignins

AbstractPolyolefins used in building materials and furniture require the use of flame-retardant (FR) additives to improve their fire safety. Such additives should be safe to humans and the environment, and preferably bio-based. In the present work, the FR performance of unmodified and chemically modified technical lignins was compared to that of the ammonium polyphosphate/pentaerythritol (APP/PER) intumescent system in a polypropylene (PP) matrix. Micro-scale combustion calorimetry (MCC) was used to study the peak heat release rate (PHR), temperature at PHR (TPHR), total heat release (THR) and char yield upon thermal decomposition of milligram-scale specimens. The PP/lignin composites showed up to 41% lower PHR and up to 36% lower THR compared to pure PP as well as large char residues. Based on the same parameters, especially the PP/lignin composites made with modified lignins outperformed the reference PP/APP/PER system and the PP/APP/lignin composites where unmodified lignin was used with APP. The most promising PP/lignin composites were prepared with partially demethylated/demethoxylated and depolymerised kraft lignin (‘CatLignin’), modified by the Mannich reaction to a nitrogen content of 13.5%.

Structural Characterization of Organostannane — Kraft Lignin

1991 ◽  
pp. 111-118 ◽  
Author(s):  
Charles E. Carraher ◽  
Dorothy C. Sterling ◽  
Thomas H. Ridgway ◽  
J. William Louda
Keyword(s):  
Structural Characterization ◽  
Kraft Lignin

New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

1990 ◽  
Vol 48 (3) ◽  
pp. 582-583
Author(s):  
S. F. Hayes ◽  
M. D. Corwin ◽  
T. G. Schwan ◽  
D. W. Dorward ◽  
W. Burgdorfer
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Structural Characterization ◽  
Negative Staining ◽  
Low Speed ◽  
Thin Sectioning ◽  
Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

Structural characterization of the PPIase domain of FKBP51, a cochaperone of human Hsp90

2011 ◽  
Vol 44 (06) ◽  
Author(s):  
A Bracher ◽  
C Kozany ◽  
AK Thost ◽  
F Hausch
Keyword(s):  
Structural Characterization ◽  
Ppiase Domain
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