scholarly journals Ferulic Acid as Building Block for the Lipase-Catalyzed Synthesis of Biobased Aromatic Polyesters

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3693
Author(s):  
Alfred Bazin ◽  
Luc Avérous ◽  
Eric Pollet

Enzymatic synthesis of aromatic biobased polyesters is a recent and rapidly expanding research field. However, the direct lipase-catalyzed synthesis of polyesters from ferulic acid has not yet been reported. In this work, various ferulic-based monomers were considered for their capability to undergo CALB-catalyzed polymerization. After conversion into diesters of different lengths, the CALB-catalyzed polymerization of these monomers with 1,4-butanediol resulted in short oligomers with a DPn up to 5. Hydrogenation of the double bond resulted in monomers allowing obtaining polyesters of higher molar masses with DPn up to 58 and Mw up to 33,100 g·mol−1. These polyesters presented good thermal resistance up to 350 °C and Tg up to 7 °C. Reduction of the ferulic-based diesters into diols allowed preserving the double bond and synthesizing polyesters with a DPn up to 19 and Mw up to 15,500 g·mol−1 and higher Tg (up to 21 °C). Thus, this study has shown that the monomer hydrogenation strategy proved to be the most promising route to achieve ferulic-based polyester chains of high DPn. This study also demonstrates for the first time that ferulic-based diols allow the synthesis of high Tg polyesters. Therefore, this is an important first step toward the synthesis of competitive biobased aromatic polyesters by enzymatic catalysis.

2020 ◽  
Vol 16 (5) ◽  
pp. 606-610
Author(s):  
Nguyen T. Diep ◽  
Luu D. Huy

Background: Vietnam currently imports up to 90% of the pharmaceuticals it consumes and 100% of the steroid-based pharmaceuticals. The ability for efficient chemical synthesis of the steroids could create commercial opportunities to address this issue. Synthesis of 21-acetoxypregna-1,4,9(11)- triene-17α,21-diol-3,20-dione is considered a key intermediate in the scheme of steroidal drug synthesis. Previous synthesis attempts of such steroids (corticoids) introduce a double bond at C-1(2) in the final stage of synthesis, which delivers a poor yield and reduces the economic efficiency of the process. Objective: To study and develop a novel and effective method for the synthesis of 21-acetoxypregna- 1,4,9(11)-triene-17α,21-diol-3,20-dione. Methods: Using 9α-hydroxyandrostenedione as a substrate chemical synthesis was performed as follows: pregnane side chain construction at C-17 (acetylene method), introduction of C-1(2) double bond (using SeO2), epimerization of C-17 (via 17-ONO2 ester) and Stork’s iodination. Results: 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione was prepared from 9α- hydroxyandrostenedione with an improved yield compared to previous attempts. Conclusion: Here, 21-acetoxypregna-1,4,9(11)-triene-17α,21-diol-3,20-dione has been synthesized from 9α-hydroxyandrostenedione based on a novel, effective and commercially feasible scheme. The introduction of the C-1(2) double bond at an earlier stage of the synthesis has increased the economic efficiency of the entire process. For the first time, the indirect epimerization mechanism has been clarified along with the configuration of the C-17 stereo-center which has been confirmed using NOESY data.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elisa Di Giorgio ◽  
Marco Lunghi ◽  
Giorgio Vallortigara ◽  
Francesca Simion

AbstractThe human visual system can discriminate between animate beings vs. inanimate objects on the basis of some kinematic cues, such as starting from rest and speed changes by self-propulsion. The ontogenetic origin of such capability is still under debate. Here we investigate for the first time whether newborns manifest an attentional bias toward objects that abruptly change their speed along a trajectory as contrasted with objects that move at a constant speed. To this end, we systematically manipulated the motion speed of two objects. An object that moves with a constant speed was contrasted with an object that suddenly increases (Experiment 1) or with one that suddenly decreases its speed (Experiment 2). When presented with a single speed change, newborns did not show any visual preference. However, newborns preferred an object that abruptly increases and then decreases its speed (Experiment 3), but they did not show any visual preference for the reverse sequence pattern (Experiment 4). Overall, results are discussed in line with the hypothesis of the existence of attentional biases in newborns that trigger their attention towards some visual cues of motion that characterized animate perception in adults.


1999 ◽  
Vol 23 (11) ◽  
pp. 648-649
Author(s):  
Abdul Aziz Al-Naggar ◽  
Mervat Mohammed Abdel-Khalik ◽  
Mohammed Hilmy Elnagdi

Benzotriazolylacetone is coupled with aromatic diazonium salts to yield arylhydrazones, which can be condensed with ethyl cyanoacetate yielding pyridazinones whose reactivity towards activated double bond systems is investigated.


2014 ◽  
Vol 2 (15) ◽  
pp. 5427-5433 ◽  
Author(s):  
Shugang Li ◽  
Zhongcheng Yuan ◽  
Jianyu Yuan ◽  
Ping Deng ◽  
Qing Zhang ◽  
...  

An expanded isoindigo unit (IBTI) has been incorporated into a donor–acceptor conjugated polymer for the first time. The PCE of the solar cell device based on the new polymer reached 6.41% with a fill factor of 0.71.


Kavkaz-forum ◽  
2020 ◽  
Author(s):  
Л.Б. ДЗАПАРОВА

Проблемы теории и практики художественного перевода как феномена межкультурной коммуникации в наше время актуализируются в современной филологической науке. Расширяется исследовательское поле в этой области научного знания для переводоведов и всех, кто интересуется проблемами диалога культур. Выбор темы исследования обусловлен и прошедшим в этом году 95-летим юбилеем известного осетинского поэта, драматурга, литературоведа Нафи Григорьевича Джусойты. В статье рассматривается вклад народного писателя Осетии в теоретическое осмысление проблем художественного перевода; впер­вые анализируется одно из самых сложных для перевода стихотворений А.С. Пушкина «Пророк» в интерпретации Н. Джусойты. В частности, автором в статье представлен анализ опубликованных Джусойты на страницах центральных литературных журналов дискуссионных работ по наиболее актуальным проблемам переводоведения. В них Джусойты фокусирует внимание на вопросах верности перевода оригиналу, повышения качества подстрочников, новаторства и модер­низации классических произведений; обуславливает важность переводческого чтения в процессе постижения оригинала; определяет специфику поэтического перевода; выступает против украшательства в переводе, демонстрации на всесоюзном уровне слабых оригиналов и несовершенных переводов. В целом, Джусойты, полемизируя с известными теоретиками, предлагает свою концепцию перевода, начиная от выбора произведения и до конечного результата – текста на другом языке. Перед нами круг проблем, которые до сих пор волнуют специалистов по художественно­му переводу. Автором статьи также представлен сравнительно-сопоставительный анализ стихотворения А. Пушкина в оригинале и в переводческой интерпретации Н.Г. Джусойты. Сличение текстов на смысловом уровне показало стремление Джусойты найти художественные средства, которые помогают раскрыть основной образ. Но не везде раскрыт двуплановый смысл, запечатленный в лексических единицах исходного языка. The problems of the theory and practice of literary translation as a phenomenon of intercultural communication are still actualized in modern philological science. The research field in this area of scientific knowledge is expanding for translators and those interested in the problems of the dialogue of cultures. The choice of the research topic was also conditioned by the 95th anniversary of the famous Ossetian poet, playwright, literary critic Nafi Grigorievich Jusoyty, celebrated this year. The article examines the contribution of the people’s writer of Ossetia to the theoretical understanding of the problems of literary translation; for the first time one of the most difficult poems for translation by A.S. Pushkin’s «Prophet» in the interpretation of N. Jusoyty is reviewed. In particular, the author in the article presents an analysis of the discussion papers published by Jusoyty on the pages of central literary journals on the most pressing problems of translation studies. In them, Jusoyty focuses on the issues of closeness to the original, improving the quality of interlinear translations, innovation and modernization of classical works; determines the importance of translation reading in the process of comprehending the original; determines the specifics of poetic translation; opposes embellishment in translation, the demonstration of weak originals and imperfect translations at the all-Union level. In general, Jusoyty, arguing with well-known theorists, offers his own concept of translation, starting from the choice of a work and up to the final result – a text in another language. We are faced with a range of problems that still concern specialists in literary translation. The author of the article also presents a comparative analysis of A. Pushkin’s poem in the original and in t/he translation interpretation of N.G. Jusoyty. Comparison of the texts at the semantic level showed Jusoyty’s desire to find close artistic means that help to reveal the main image. But not everywhere is disclosed the two-dimensional meaning embodied in the lexical units of the source language.


2021 ◽  
Vol 7 ◽  
pp. 316-326
Author(s):  
Лідія Лазурко ◽  

The purpose of the research – is to demonstrate how the historiographic image of Wilhelm von Habsburg, known as Colonel Vasyl Vyshyvanyi, was constructed on the basis of sources of personal origin and historiography materials that were deposited during the XX century. In the first time in historiography shown as the as the story of the Austrian archduke, who decided to change his national identity and chose for himself the image of a fighter for the will of Ukraine, unfolded and mythologized. The history of the life of the Austrian Archduke Wilhelm von Habsburg-Lötringen has in recent years been enriched by a number of thorough studies. The main issue of this research was the question of choosing a Ukrainian national identity. The construction of the Ukrainian legend Vasyl Vyshyvany in the historiography began, based on his own autobiography. As the accumulation of source and scientific material, the question of the vision of the hero evolved: from explaining the circumstances of change of national self-identification to exploring the motives of this step. Changes in the interpretation of this issue were also outlined and brought to the cultural and philosophical research field.


2015 ◽  
Vol 17 (37) ◽  
pp. 23704-23710 ◽  
Author(s):  
Jingchao Zhang ◽  
Yang Hong ◽  
Zhen Tong ◽  
Zhihuai Xiao ◽  
Hua Bao ◽  
...  

For the first time, the interfacial thermal resistance between silicene and multiple substrates,i.e., crystalline silicon and silica, amorphous silicon and silica are calculated using a transient heating molecular dynamics technique.


2019 ◽  
Vol 485 ◽  
pp. 107819 ◽  
Author(s):  
Laura Beswick ◽  
Sanaz Ahmadipour ◽  
Jonathan P. Dolan ◽  
Martin Rejzek ◽  
Robert A. Field ◽  
...  

Synthesis ◽  
2020 ◽  
Vol 52 (22) ◽  
pp. 3446-3451
Author(s):  
Songlin Zhang ◽  
Dengbing Xie ◽  
Yiqiong Wang ◽  
Bo Yang

The carbon–carbon double bond formation via neodymium-mediated Barbier-type reaction of ketones and allyl halides in the presence of diethyl phosphite is reported for the first time. The reaction is highly α-regioselective and was conveniently carried out under mild conditions in a one-pot fashion. From a synthetic point of view, a series of conjugated alkenes were obtained in moderate to good yields in this one-pot reaction with feasible reaction conditions.


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