scholarly journals Reductive Functionalization of Amides in Synthesis and for Modification of Bioactive Compounds

2021 ◽  
Vol 9 ◽  
Author(s):  
Paweł J. Czerwiński ◽  
Bartłomiej Furman
Keyword(s):  
Natural Products ◽  
Bioactive Compounds ◽  
Late Stage ◽  
Main Axis ◽  
Synthetic Approach ◽  
Condensed Form ◽  
Amide Reduction ◽  
Synthetic Application

In this review, applications of the amide reductive functionalization methodology for the synthesis and modification of bioactive compounds are covered. A brief summary of the different protocols is presented in the introduction, followed by the synthetic application of these in late-stage functionalization, leading to known pharmaceuticals or to their derivatives, including bioisosteres, with potential higher activity as the main axis of the article. The synthetic approach to natural products based on amide reduction is also discussed; however, this is given in a condensed form focusing on recent or as yet unexplored applications due to a number of recently published excellent reviews covering this topic. The aim of this review is to illustrate the potential of reductive functionalization of amides as an elegant and useful tool in the synthesis of bioactive compounds and inspire further work in this field.

Direct Preparation of Indole Hemiaminals through Organocatalytic Nucleophilic Addition of Indole to Aldehydes

Synthesis ◽  
2018 ◽  
Vol 50 (20) ◽  
pp. 4063-4070 ◽  
Author(s):  
Wenling Qin ◽  
Nan Zhang ◽  
Yige Li ◽  
Zhili Chen
Keyword(s):  
Natural Products ◽  
Bioactive Compounds ◽  
Late Stage ◽  
Nucleophilic Addition ◽  
Reaction Conditions ◽  
Direct Preparation

Hemiaminals are common in natural products as well as bioactive compounds. Hemiaminals with an indole moiety are particularly attractive due to the significant bioactivity of indoles. Herein, we reported an efficient organocatalyzed indole N-1 nucleophilic addition of α-oxoaldehydes to deliver various indole hemiaminals in good yields (up to 92%) and excellent regioselectivities with DABCO or triethylamine as the catalyst. The method is characterized by mild reaction conditions, widely available reagents, and general substrate scope, and it is also applicable to late-stage transformations without affecting the hemiaminal group. In addition, we carried out this reaction in an enantioselective fashion in good yields and high ee values with two general substrates.

scholarly journals Visible light mediated photocatalytic [2 + 2] cycloaddition/ring-opening rearomatization cascade of electron-deficient azaarenes and vinylarenes

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Noelia Salaverri ◽  
Rubén Mas-Ballesté ◽  
Leyre Marzo ◽  
José Alemán
Keyword(s):  
Natural Products ◽  
Double Bond ◽  
Visible Light ◽  
Bioactive Compounds ◽  
Late Stage ◽  
Ring Opening ◽  
Functional Group ◽  
Theoretical Calculations ◽  
Double Bonds ◽  
Heterocyclic Derivatives

Abstract The broad presence of azaarene moieties in natural products has promoted the development of new functionalization reactions, giving access to larger libraries of bioactive compounds. The light promoted [2 + 2] photocycloaddition reaction to generate cyclobutanes has been extensively studied in photochemistry. In particular, De Mayo reported the [2 + 2] cycloaddition followed by retroaldol condensation between enols of 1,3-dicarbonyls and double bonds to synthesize 1,5-dicarbonyls. Herein, we describe the [2 + 2] photocycloaddition followed by a ring-opening rearomatization reaction between electron-deficient 2-methylene-azaarenes and double bonds, taking advantage of the ability of these heterocyclic derivatives to form the corresponding pseudo-enamine intermediate. The procedure shows a high functional group tolerance either on the double bond or the heteroarene side and allows the presence of different electron-withdrawing groups. In addition, the wide applicability of this reaction has been demonstrated through the late-stage derivatization of several natural products. Photochemical studies, together with theoretical calculations, support a mechanism involving the photosensitization of the pseudo-enamine intermediate.

Synthesis of Spongidine A, D and Petrosaspongiolide L Methyl Ester Using Pyridine C-H Functionalization

2019 ◽  
Author(s):  
Florian Bartels ◽  
Manuela Weber ◽  
Mathias Christmann
Keyword(s):  
Natural Products ◽  
Methyl Ester ◽  
Hydrogen Atom ◽  
Phospholipase A2 ◽  
Late Stage ◽  
Hydrogen Atom Transfer ◽  
Ring System ◽  
Tetracyclic Core ◽  
Intramolecular Hydrogen ◽  
Phospholipase A2 Inhibitors

<div>An efficient strategy for the synthesis of the potent phospholipase A2 inhibitors spongidine A and D is presented. The tetracyclic core of the natural products was assembled via an intramolecular hydrogen atom transfer‐initiated Minisci reaction. A divergent late‐stage functionalization of the tetracyclic ring system was also used to achieve a concise synthesis of petrosaspongiolide L methyl ester.</div>

Intramolecular Diels–Alder Reactions of Oxazoles, Imidazoles, and Thiazoles

Synthesis ◽  
2020 ◽  
Author(s):  
Peter Wipf ◽  
Thanh T. Nguyen
Keyword(s):  
Natural Products ◽  
Lewis Acid ◽  
Acid Catalysis ◽  
Copper Catalysts ◽  
Diels Alder ◽  
Synthetic Approach ◽  
Highly Efficient ◽  
Intramolecular Cycloadditions ◽  
Western Segment ◽  
Target Molecules

AbstractThe development of the intramolecular Diels–Alder cycloaddition­ of azole heterocycles, i.e. oxazoles (IMDAO), imidazoles (IMDAI), and thiazoles (IMDAT), has had a significant impact on the efficient preparation of heterocyclic intermediates and natural products. In particular, highly efficient and versatile IMDAO reactions have been utilized as a key step in several synthetic schemes to provide alkaloids and terpenoid target molecules. More limited studies have been performed on IMDAI and IMDAT cycloadditions. Some drawbacks, such as the occasionally­ challenging preparation of IMDA precursors, are also highlighted in this review. Perspectives are provided on how IMDAI and IMDAT­ transformations can be further expanded for target-directed syntheses.1 Introduction2 Oxazoles2.1 IMDAO Approaches to Furanosesquiterpenes and Furanosteroids2.1.1 Syntheses of Highly Oxygenated Sesquiterpenes2.1.2 Syntheses of (±)-Gnididione and (±)-Isognididione2.1.3 Synthesis of (±)-Stemoamide2.1.4 Synthesis of (±)-Paniculide A2.1.5 Syntheses of (+)- and (–)-Norsecurinine2.1.6 Synthesis of Evodone2.1.7 Syntheses of (±)-Ligularone and (±)-Petasalbine2.1.8 Syntheses of Imerubrine, Isoimerubrine, and Grandirubrine2.1.9 Syntheses of Furanosteroids2.1.10 Syntheses of Substituted Indolines and Tetrahydroquinolines2.2 IMDAO Approaches to Pyridines: the Kondrat’eva Reaction2.2.1 Syntheses of Suaveoline and Norsuaveoline2.2.2 Synthesis of Eupolauramine2.2.3 Syntheses of (–)-Plectrodorine and (+)-Oxerine2.2.4 Synthesis of Amphimedine2.2.5 Synthetic Approach to the Western Segment of Haplophytine2.2.6 Synthesis of Marinoquinoline A2.2.6.1 IMDAO Approach to Marinoquinoline A2.2.6.2 Scope of Allenyl IMDAO Cycloaddition2.3 Lewis Acid Catalysis in IMDAO Reactions2.3.1 Effects of Europium Catalysts on IMDAO Reactions2.3.2 Effects of Copper Catalysts on IMDAO Reactions3 Imidazoles 4 Thiazoles4.1 Syntheses of Menthane and Eremophilane4.2 Further Comments on the Intramolecular Cycloadditions of Thiocarbonyl Ylides5 Conclusions and Outlook

scholarly journals Mechanically induced solvent-free esterification method at room temperature

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5080-5085
Author(s):  
Lei Zheng ◽  
Chen Sun ◽  
Wenhao Xu ◽  
Alexandr V. Dushkin ◽  
Nikolay Polyakov ◽  
...  
Keyword(s):  
Natural Products ◽  
Carboxylic Acids ◽  
Late Stage ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Solvent Free ◽  
Mild Conditions

We have developed I2/KH2PO2 and KI/P(OEt)3 strategy syntheses of esters from carboxylic acids and alcohols through different reaction mechanisms. The advantages of present protocol: mild conditions and late-stage diversification of natural products.

ChemInform Abstract: Eight Membered Ethers via Diene Metathesis: Synthetic Approach to Laureatin Natural Products.

ChemInform ◽  
2010 ◽  
Vol 30 (33) ◽  
pp. no-no
Author(s):  
Simon D. Edwards ◽  
Terence Lewis ◽  
Richard J. K. Taylor
Keyword(s):  
Natural Products ◽  
Synthetic Approach ◽  
Diene Metathesis

scholarly journals Chemical Diversity and Biological Activity of Secondary Metabolites Isolated from Indonesian Marine Invertebrates

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1898
Author(s):  
Fauzia Izzati ◽  
Mega Ferdina Warsito ◽  
Asep Bayu ◽  
Anggia Prasetyoputri ◽  
Akhirta Atikana ◽  
...  
Keyword(s):  
Natural Products ◽  
Bioactive Compounds ◽  
Marine Natural Products ◽  
Biological Function ◽  
Marine Invertebrates ◽  
Biological Activities ◽  
Structural Diversity ◽  
Chemical Diversity ◽  
Soft Corals ◽  
High Chemical

Marine invertebrates have been reported to be an excellent resource of many novel bioactive compounds. Studies reported that Indonesia has remarkable yet underexplored marine natural products, with a high chemical diversity and a broad spectrum of biological activities. This review discusses recent updates on the exploration of marine natural products from Indonesian marine invertebrates (i.e., sponges, tunicates, and soft corals) throughout 2007–2020. This paper summarizes the structural diversity and biological function of the bioactive compounds isolated from Indonesian marine invertebrates as antimicrobial, antifungal, anticancer, and antiviral, while also presenting the opportunity for further investigation of novel compounds derived from Indonesian marine invertebrates.

An Indirect Synthetic Approach toward Conformationally Constrained 20-Membered Unclosed Cryptands via Late-Stage Installation of Intraannular Substituents

2018 ◽  
Vol 83 (21) ◽  
pp. 13560-13567 ◽  
Author(s):  
Janusz Jurczak ◽  
Adam Sobczuk ◽  
Kajetan Da̧browa ◽  
Marcin Lindner ◽  
Patryk Niedbała
Keyword(s):  
Late Stage ◽  
Synthetic Approach ◽  
Conformationally Constrained
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