Chemical Diversity of Volatile Macrocylic Lactones from Frogs

Synlett ◽  
2021 ◽  
Author(s):  
Stefan Schulz ◽  
Dennis Poth ◽  
Pardha Saradhi Peram ◽  
Susann Hötling ◽  
Markus Menke ◽  
...  

AbstractFor a long time, frogs were believed to communicate primarily via the acoustic channel, but during the last decades it became obvious that various lineages also use chemical communication. In this Account we present our research on the identification of volatile lactones from Madagascan Mantellidae and African Hyperoliidae frogs. Both possess male specific glands that can disseminate a range of volatile compounds. Key constituents are macrocyclic lactones. They show high variability in structure and occurrence. We focus here on the synthetic approaches we have used to clarify constitution and configuration of the glandular compounds. Key synthetic methods are ring-closing metathesis and nucleophilic epoxide opening. Often, but not always, the natural compounds occurs in amounts that excludes their investigation by NMR spectroscopy. Instead, we use GC/MS analysis, GC/IR, microreactions, and synthesis to identify such components. Several aspects of our work will be described giving some insight in our scientific approach.1 Introduction2 Macrocylic Lactones from the Fatty Acid Biosynthetic Pathway3 Unsaturated Lactones4 Terpenoid Lactones5 Macrolide Occurrence6 Conclusions

Synthesis ◽  
2017 ◽  
Vol 49 (22) ◽  
pp. 4899-4916 ◽  
Author(s):  
Rongbiao Tong ◽  
Zhihong Zhang

Being different from 2,6-cis-tetrahydropyrans (2,6-cis-THPs), the corresponding 2,6-trans-THPs are thermodynamically less stable and more challenging to construct. The fact that there are many natural products and/or bioactive molecules containing this 2,6-trans-THP subunit has led to the development of many efficient synthetic approaches to access 2,6-trans-THPs. This review summarizes various synthetic methods reported for this structural motif and/or related applications in the total synthesis of natural products.1 Introduction2 Nucleophilic Addition to an Oxocarbenium Ion (Strategy A)3 Intramolecular Oxa-Michael Addition (Strategy B)4 Intermolecular Michael Addition to Dihydropyranones (Strategy A)5 The Heck–Matsuda (Strategy A) Reaction and Oxa-Heck Cyclization (Strategy B)6 Intramolecular SN2 Substitution and Epoxide Opening (Strategy B)7 Miscellaneous Methods8 Conclusion and Outlook


2020 ◽  
Vol 27 ◽  
Author(s):  
Sunil Kumar ◽  
Yu-Chia Chang ◽  
Kuei-Hung Lai ◽  
Tsong-Long Hwang

Background: Resveratrol, a natural polyphenol product, is used in plant defense from fungal and microbial aggression. It is found naturally, especially in plants such as grapes, peanuts, and berries. It has the highest concentrations in blueberries, mulberries, blackberries, and the skin of red grapes. Resveratrol has various pharmacological properties such as anti-inflammatory, cytoprotective, and antineoplastic activities. Methods: We conducted a literature survey using standard tools such as Google, Reaxys, Scifinder, Scihub, and patent Espacenet to compile the biosynthetic pathways, all organic synthetic methods, and biological activities reported for resveratrol till date. Results: More than one hundred research articles and patents were referred to write this review. About twenty-five of them are related to chemical synthesis, and the rests are about the source, pharmacological activity, and other properties of resveratrol. This study reveals that many common pathways are involved in various pharmacological activities, which can be useful for treating various diseases based on the pathways involved. Reactions such as Pfitzner-Moffatt oxidation, WittigHorner condensation, Mizoroki–Heck, Perkin, Wittig, etc. have been used in resveratrol synthesis. A structure-activity relationship was also established based on its analogs and derivatives. Conclusion: This review examined and reported all the published biological activities and chemical syntheses of resveratrol apart from the biosynthetic pathway. Due to its valuable biological activities, various synthetic approaches have been reported till date. The reported synthetic operations are suitable for large-scale industrial production. Moreover, these comprehensive synthetic procedures could be utilized in the preparation of stilbenes and other related compounds in future endeavors.


2019 ◽  
Vol 16 (3) ◽  
pp. 342-368 ◽  
Author(s):  
Ramandeep Kaur ◽  
Yagyesh Kapoor ◽  
Sundeep K. Manjal ◽  
Ravindra K. Rawal ◽  
Kapil Kumar

The furo [2,3-b] indoline ring system is one of the most important structural units in various natural products. It has been known to have inherent biological activities and is utilized as a synthetic target for a number of natural compounds; therefore, this has contributed to a great demand for the growth of synthetic methods for this ring system. Most important compounds with furoindoline ring system are physovenine, madindoline A and B and makomotindoline etc. These compounds are well known to exhibit biological activity against different diseases such as glaucoma, cancer, cachexia, Castleman’s disease, rheumatoid arthritis, etc. The current article focuses on various synthetic approaches for furoindoline containing compounds and essential furoindoline moiety, such as oxindole-5-O-tetrahydropyranyl ether route etc., and various other diastereoand enantio- controlled approach in a very concise way.


2021 ◽  
Author(s):  
Yan-Hong Zou ◽  
Hai-Ning Wang ◽  
Xing Meng ◽  
Hong-Xu Sun ◽  
Zi-Yan Zhou

Different synthetic approaches give birth to different structures, which result in varied photocatalytic performances.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ryota Akiyama ◽  
Bunta Watanabe ◽  
Masaru Nakayasu ◽  
Hyoung Jae Lee ◽  
Junpei Kato ◽  
...  

AbstractPotato (Solanum tuberosum), a worldwide major food crop, produces the toxic, bitter tasting solanidane glycoalkaloids α-solanine and α-chaconine. Controlling levels of glycoalkaloids is an important focus on potato breeding. Tomato (Solanum lycopersicum) contains a bitter spirosolane glycoalkaloid, α-tomatine. These glycoalkaloids are biosynthesized from cholesterol via a partly common pathway, although the mechanisms giving rise to the structural differences between solanidane and spirosolane remained elusive. Here we identify a 2-oxoglutarate dependent dioxygenase, designated as DPS (Dioxygenase for Potato Solanidane synthesis), that is a key enzyme for solanidane glycoalkaloid biosynthesis in potato. DPS catalyzes the ring-rearrangement from spirosolane to solanidane via C-16 hydroxylation. Evolutionary divergence of spirosolane-metabolizing dioxygenases contributes to the emergence of toxic solanidane glycoalkaloids in potato and the chemical diversity in Solanaceae.


Author(s):  
Luana da S. M. Forezi ◽  
Acácio S. de Souza ◽  
Carolina G. S. Lima ◽  
Amanda A. Borges ◽  
Patricia G. Ferreira ◽  
...  

: Naphthoquinones are important molecules belonging to the general class of quinones, and many of these compounds have become drugs that are in the pharmaceutical market for the treatment of several diseases. A special subclass of compounds is that of the bis(naphthoquinones), which have two linked naphthoquinone units. In the last few years, several synthetic approaches toward such valuable compounds have been described, as well as their evaluation against numerous important biological targets. In this review, we provide a thorough discussion on the various synthetic methods reported for the synthesis of bis(naphthoquinone) analogues, also highlighting the biological activities of these substances.


2015 ◽  
Vol 13 (5) ◽  
pp. 285-292 ◽  
Author(s):  
Thao Ung ◽  
Jennifer L. Mason ◽  
Ron G. Robinson ◽  
Chrysanthe M. Spais ◽  
Mark A. Ator ◽  
...  

Problemos ◽  
2011 ◽  
Vol 79 ◽  
pp. 129-140
Author(s):  
Mindaugas Briedis

Nors fenomenologinė filosofija jau kurį laiką daro įtaką psichoterapeutų darbo metodams, galima teigti, kad pastarieji naudojasi egzistencialistinėmis fenomenologijos traktuotėmis, o štai pirminis, dar Edmundo Husserlio inicijuotas projektas išleidžiamas iš akių. Straipsnyje kaip tik ir užsibrėžiama grįžti prie pastarojo fenomenologijos supratimo, nagrinėjant metodologines psichologijos problemas bei nužymint galimas psichoterapijos perspektyvas. Pirmoje dalyje aptariamos metodologinės ir tipologinės psichoterapijos problemos. Teigiama, kad empirinė psichoterapija neteikia galimybių iš esmės užčiuopti ego struktūros – tikrosios žmogiškojo patyrimo ir atitinkamai psichinių konfliktų erdvės. Sykiu pateikiama fenomenologinė žinojimo traktuotė, psichologinio bet transcendentalinio ego perskyra bei kitos pamatinės, psichoterapijos uždavinius reformuluojančios fenomenologijos temos. Antroje dalyje kaip viena iš galimų fenomenologijos ir psichologijos koreliacijos perspektyvų pateikiama kritinė lyginamoji Sigmundo Freudo sąmonės ir pasąmonės bei „atitinkama“ Husserlio impresinės (produktyvios) ir reproduktyvios sąmonės teorijų analizė, nepamirštant, kad Freudo psichoanalizės jokiu būdu negalima tapatinti su psichoterapija apskritai. Parodoma, kad Husserlio žodynas leidžia naujai konstruktyviai perskaityti Freudo pastabas apie instinktyvaus skatulio teorijos dėsningumus bei represavimo mechanizmą. Trečioje dalyje glaustai suformuluojamos bendros fenomenologinės hermeneutikos rekomendacijos psichoterapeutams. Straipsnyje jokiu būdu neteigiama, kad fenomenologija gali ar turi pakeisti psichoterapiją, tačiau numatoma, kad kaip ir kiekviena teorinė-praktinė disciplina, psichoterapija gali ir turi atrasti fenomenologiją kaip savo atspirties ir plėtotės tašką.Pagrindiniai žodžiai: fenomenologija, psichoterapija, psichologinis ir transcendentalinis ego, instinktyvus skatulys, psichiniai sutrikimai, reproduktyvi sąmonė.E. Husserl’s Phenomenological Project and the Problems Concerning PsychotherapyMindaugas Briedis SummaryThough phenomenological philosophy has influenced practitioners of psychotherapy for a long time, it is also true, that it was precisely existentialist approach to phenomenology that was exploited, while the whole initial project of phenomenology initiated by E. Husserl was almost forgotten. In this article I beckon to re-enter this initial understanding of phenomenology, considering methodological problems of psychology and laying down possible perspectives for psychotherapy.First part of the article deals with the methodological problems of psychotherapy while raising the thesis that empirical psychotherapy in principle cannot grasp the ego-structure, misses the true depth of the human experience, which in turn is the real sphere of mental disorders. Hand in hand goes the phenomenological critique of the scientific approach and other phenomenological issues relevant to the reformulation of the goals of psychotherapy.Second part of the article is dedicated to the one of many possible perspectives stemming from the correlation between phenomenology and psychotherapy, i.e. critical comparison of S. Freud’s consciousness and unconsciousness and “corresponding” theory of impressional (productive) and reproductive consciousness presented by Husserl. It is indicated that Husserl’s approach enables new and constructive reading of Freud’s theory of instinctual drive while keeping in mind, that Freud’s psychoanalysis cannot be identified with psychotherapy in general. However, the final part of the article suggests some methodological advices for mental care practice from the perspective of phenomenological hermeneutics.Keywords: phenomenology, psychotherapy, psychological and transcendental ego, instinctive drive, mental disorders, reproductive consciousness.


Marine Drugs ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. 292 ◽  
Author(s):  
Pablo García ◽  
Ángela Hernández ◽  
Arturo San Feliciano ◽  
Mª Castro

The sea is a rich source of biological active compounds, among which terpenyl-quinones/hydroquinones constitute a family of secondary metabolites with diverse pharmacological properties. The chemical diversity and bioactivity of those isolated from marine organisms in the last 10 years are summarized in this review. Aspects related to synthetic approaches towards the preparation of improved bioactive analogues from inactive terpenoids are also outlined.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2417 ◽  
Author(s):  
Jong-Wha Jung ◽  
Nam-Jung Kim ◽  
Hwayoung Yun ◽  
Young Han

4-Arylcoumarins (4-aryl-2H-1-benzopyran-2-one), also known as neoflavones, comprise a minor subclass of naturally occurring flavonoids. Because of their broad-spectrum biological activities, arylcoumarins have been attracting the attention of the organic and medicinal chemistry communities, and are considered as an important privileged scaffold. Since the development of Pechmann condensation, a classical acid-catalyzed condensation between phenol and β-keto-carboxylic acid, several versatile and efficient synthetic approaches for 4-arylcoumarins have been reported. This review summarizes recent advances in the synthesis of the 4-arylcoumarin scaffold by classifying them based on the final bond-formation type. In particular, synthetic methods executed under mild and highly efficient conditions, such as solvent-free reactions and transition metal catalysis, are highlighted.


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