scholarly journals Synthetic Approaches to a Challenging and Unusual Structure—An Amino-Pyrrolidine Guanine Core

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 797
Author(s):  
Rafael Rippel ◽  
Luís Pinheiro ◽  
Mónica Lopes ◽  
Ana Lourenço ◽  
Luísa M. Ferreira ◽  
...  

The synthesis of an unreported 2-aminopyrrolidine-1-carboxamidine unit is here described for the first time. This unusual and promising structure was attained through the oxidative decarboxylation of amino acids using the pair of reagents, silver(I)/peroxydisulfate (Ag(I)/S2O82−) followed by intermolecular (in the case of l-proline derivative) and intramolecular trapping (in the case of acyl l-arginine) by N-nucleophiles. The l-proline approach has a broader scope for the synthesis of 2-aminopyrrolidine-1-carboxamidine derivatives, whereas the intramolecular cyclization afforded by the l-acylarginines, when applied, results in higher yields. The former allowed the first synthesis of cernumidine, a natural alkaloid isolated in 2011 from Solanum cernuum Vell, as its racemic form.

2018 ◽  
Author(s):  
Nidhi Gour ◽  
Bharti Koshti ◽  
Chandra Kanth P. ◽  
Dhruvi Shah ◽  
Vivek Shinh Kshatriya ◽  
...  

We report for the very first time self-assembly of Cysteine and Methionine to discrenible strucutres under neutral condition. To get insights into the structure formation, thioflavin T and Congo red binding assays were done which revealed that aggregates may not have amyloid like characteristics. The nature of interactions which lead to such self-assemblies was purported by coincubating assemblies in urea and mercaptoethanol. Further interaction of aggregates with short amyloidogenic dipeptide diphenylalanine (FF) was assessed. While cysteine aggregates completely disrupted FF fibres, methionine albeit triggered fibrillation. The cytotoxicity assays of cysteine and methionine structures were performed on Human Neuroblastoma IMR-32 cells which suggested that aggregates are not cytotoxic in nature and thus, may not have amyloid like etiology. The results presented in the manuscript are striking, since to the best of our knowledge,this is the first report which demonstrates that even non-aromatic amino acids (cysteine and methionine) can undergo spontaneous self-assembly to form ordered aggregates.


Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 481
Author(s):  
Gemma G. Martínez-García ◽  
Raúl F. Pérez ◽  
Álvaro F. Fernández ◽  
Sylvere Durand ◽  
Guido Kroemer ◽  
...  

Autophagy is an essential protective mechanism that allows mammalian cells to cope with a variety of stressors and contributes to maintaining cellular and tissue homeostasis. Due to these crucial roles and also to the fact that autophagy malfunction has been described in a wide range of pathologies, an increasing number of in vivo studies involving animal models targeting autophagy genes have been developed. In mammals, total autophagy inactivation is lethal, and constitutive knockout models lacking effectors of this route are not viable, which has hindered so far the analysis of the consequences of a systemic autophagy decline. Here, we take advantage of atg4b−/− mice, an autophagy-deficient model with only partial disruption of the process, to assess the effects of systemic reduction of autophagy on the metabolome. We describe for the first time the metabolic footprint of systemic autophagy decline, showing that impaired autophagy results in highly tissue-dependent alterations that are more accentuated in the skeletal muscle and plasma. These changes, which include changes in the levels of amino-acids, lipids, or nucleosides, sometimes resemble those that are frequently described in conditions like aging, obesity, or cardiac damage. We also discuss different hypotheses on how impaired autophagy may affect the metabolism of several tissues in mammals.


2021 ◽  
Author(s):  
Zhiqiang Pan ◽  
Fengchi Hu ◽  
Di Jiang ◽  
Yuchang Liu ◽  
Chengfeng Xia

The photoexcited enamines derived from α-amino acids could undergo an oxidative decarboxylation followed by a Chichibabin cyclization to afford highly substituted pyridiniums.


2021 ◽  
Author(s):  
Jin-Tian Ma ◽  
Li-Sheng Wang ◽  
Zhi Chai ◽  
Xin-Feng Chen ◽  
Bo-Cheng Tang ◽  
...  

Quinazoline skeletons are synthesized by amino acids catabolism/reconstruction combined with dimethyl sulfoxide insertion/cyclization for the first time. The amino acid acts as a carbon and nitrogen source through HI-mediated catabolism...


ChemInform ◽  
1989 ◽  
Vol 20 (26) ◽  
Author(s):  
M. OCHIAI ◽  
M. INENAGA ◽  
Y. NAGAO ◽  
R. M. MORIARTY ◽  
R. K. VAID ◽  
...  

Fitoterapia ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 44-50
Author(s):  
S.M. Marchyshyn ◽  
◽  
L.V. Slobodianiuk ◽  
R.Yu. Basaraba ◽  
N.А. Hudz ◽  
...  

Keywords: amino acids; common pussytoes; yacon; stevia; golden marigolds; leaves; herb; aster family; high performance liquid chromatography. For the first time the qualitative composition was studied and the quantitative content of amino acids in the herb of common pussytoes, yacon leaves, stevia leaves, herb of golden marigolds was determined by HPLC. 17 bound and 16 free amino acids were identified in the herb of common pussytoes, in the herb of golden marigolds, yacon leaves and stevia leaves – 12 and 5, 17 and 11 and 16 and 14 amino acids, respectively. The highest content of the sum of essential and substitute amino acids is contained in the leaves of stevia; the lowest content of the sum of essential amino – in the herb of golden marigolds, the sum of essential amino acids – in the herb of common pussytoes.


2021 ◽  
pp. 83-87
Author(s):  
Леонид Чеславович Бурак ◽  
Андрей Петрович Завалей

Авторами статьи впервые разработана технология производства соков прямого отжима и высокой концентрации из плодов бузины садовой и дикорастущей, собранных на территории Беларуси. Сок прямого отжима получали при помощи ферментации с последующей фильтрацией. Концентрированный сок был получен из сока прямого отжима и экстрагирования выжимок. Для максимального извлечения сока после дробления при ферментативной обработке была использована температура 50 °С в течение 240 мин, количество ферментного препарата составляло 400 см/т. Были исследованы органолептические и физико-химические показатели сока прямого отжима и сока концентрированного: массовая доля сухих веществ, aктивная кислотность (рН), массовая доля пектиновых веществ, cодержание антоцианов, белка, массовая доля органических кислот. Исследованы показатели безопасности продукции, впервые определен состав аминокислот (качество и количество) в концентрированном соке бузины. Установлено, что совокупность физико-химических показателей позволяет отнести сок прямого отжима из бузины к профилактическим напиткам. В состав сока бузины высокой концентрации входят 18 аминокислот в количестве 4,84 г/100 мл. Незаменимых аминокислот выявлено 7 в количестве 1,51 г/100 мл. Также сок суммарно содержит фенолы в соотношении 42,95 мг-экв галловой кислоты/г сухого вещества и большое количество гидролизованных танинов. При этом большинство полифенольных соединений избежали разрушения в процессе концентрации. The authors of the article developed for the first time a technological process for the production of direct-squeezed juice and concentrated juice from the fruits of garden and wild elderberry growing in the Republic of Belarus. Direct-squeezed juice was obtained by fermentation followed by filtration. Concentrated juice was obtained by processing direct-squeezed juice and extracting the marc. For maximum juice extraction after crushing during enzymatic treatment, a temperature of 50 °C was used for 240 min, the dose of the enzyme preparation was 400 cm/t. Direct-squeezed juice and concentrated juice were studied by organoleptic and physicochemical parameters: mass fraction of solids, active acidity (pH), mass fraction of pectin substances, content of anthocyanins, protein, mass fraction of organic acids. The product safety indicators were studied, the qualitative and quantitative composition of amino acids in concentrated elderberry juice was first determined. It has been established that by the combination of physicochemical parameters, direct squeezed juice from elderberry can be considered a preventive drink. The composition of concentrated elderberry juice includes 18 amino acids, in the amount of 4.84 g/100 ml. 7 essential amino acids were detected in the amount of 1.51 g/100 ml. The concentrated juice contained phenols in the quantity of 42.95 mEq gallic acid / gram dry matter and a large number of hydrolyzed tannins. Most polyphenolic compounds were preserved after the juice concentration.


2021 ◽  
Author(s):  
Rafael P. Donnarumma ◽  
Sahara Frojmovic ◽  
Paola Marino ◽  
Hudson de Aguiar Bicalho ◽  
Hatem M. Titi ◽  
...  

Rare-earth (RE) analogues of UiO-66 with non-functionalised 1,4-benzenedicarboxylate linkers are synthesised for the first time, and a series of synthetic approaches is provided to troubleshoot the synthesis. RE-UiO-66 analogues are...


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