Consecutive Ireland –Claisen Enyne-Metathesis Strategy Enables Rapid Assembly of Cyclic Imine Core Cyclohexene Motif
Synlett DOI: 10.1055/a-2215-1320 An efficient strategy for rapid assembly of the complex substituted cyclohexene core that is present in several cyclic imine marine toxins is presented. Several of these toxins, including pinnatoxin A and recently discovered portimine A, have been the focus of much attention due to their fascinating biological activities. We demonstrate that the substituted cyclohexene-diene motif, which is a challenging feature to access synthetically, can be prepared through a stepwise Ireland–Claisen rearrangement/enyne metathesis procedure beginning from chiral esters. This approach enables a divergen...
Source: Synlett - December 20, 2023 Category: Chemistry Authors: Lee, Hye Joon Gladfelder, Joshua Kandiyal, Priya Zakarian, Armen Tags: letter Source Type: research
Synthesis of Modified C-Nucleosides of Therapeutic Significant: A Succinct Account
Conclusion [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - December 20, 2023 Category: Chemistry Authors: Hudait, Nandagopal Sakander, Norein Kundu, Sanchari Rasool, Bisma Sengupta, Jhimli Mukherjee, Debaraj Tags: account Source Type: research
The Synthesis of Nitrogen- and Oxygen-Containing Heterocyclic Scaffolds Assisted by Ionic Liquids: A 2022 Literature Survey
Synlett DOI: 10.1055/a-2201-7705 Heterocycles have gained recognition as vital components in approved drugs, drawing substantial attention from the scientific community. Ionic liquids (ILs) have been utilized for their transformative roles in heterocycle synthesis, showcasing distinctive properties that are pivotal in diverse chemical transformations, while also acting as effective catalysts and offering safer alternatives to volatile organic solvents. This account delves into the synthesis of nitrogen- and oxygen-containing heterocyclic structures, employing various ILs such as ammonium, cholinium, DABCO-based, DBU-based,...
Source: Synlett - December 20, 2023 Category: Chemistry Authors: Dhameliya, Tejas M. Raghani, Neha R. Desai, Meet S. Chudasma, Shraddhaba J. Virani, Kumkum D. Tags: account Source Type: research
Evaluation of Phenyldiazenyl as a Protective/Activating Group in Lithiation –Substitution Reactions of Tetrahydroisoquinolines
Synlett DOI: 10.1055/s-0042-1751537 Phenyldiazenyl moiety has been utilized both as a protective and activating group to synthesize C-1-substituted tetrahydroisoquinolines via lithiation–substitution strategy. This reaction sequence involves generation of α-amino carbanions, derived from N-phenyldiazenyl tetrahydroisoquinolines, followed by coupling with various electrophiles, e.g., aldehyde, ketones, alkyl halide, oxiranes, isocyanates, and with in situ generated arynes. Deprotection of the protecting group was carried out under acidic conditions to afford the desired α-substituted products in moderate to good yields....
Source: Synlett - December 19, 2023 Category: Chemistry Authors: Kaur, Babaldeep Kaur, Manjot Singh, Pushpinder Sharma, Esha Batra, Aanchal Kaur, Amarjit Singh, Kamal Nain Tags: letter Source Type: research
Applying Lessons Learned from Developing Exon Skipping for Duchenne to Developing Individualized Exon Skipping Therapy for Patients with Neurodegenerative Diseases
Synlett DOI: 10.1055/a-2211-6490 Antisense oligonucleotides (ASOs) are short, modified pieces of DNA that are chemically modified. They can be used to induce exon skipping and treat Duchenne muscular dystrophy (DMD) patients by interfering with the splicing process so mutated dystrophin transcripts become readable allowing production of partially functional dystrophin proteins, rather than nonfunctional dystrophins. After over 2 decades of research, 4 ASOs are FDA approved for DMD, but clinical effects are suboptimal due to limited delivery to skeletal muscle. At the same time, ASOs for brain diseases result in much more f...
Source: Synlett - December 19, 2023 Category: Chemistry Authors: Aartsma-Rus, Annemieke Tags: account Source Type: research
BF3@K10: An Efficient Heterogeneous Montmorillonite Catalyst for the Halogenation of N-Heterocycles
Synlett DOI: 10.1055/a-2212-7627 Halogenated N-heterocycles are an essential structural building block in medicinal chemistry. Herein, we describe an economical and efficient protocol for the regioselective halogenation of several N-heterocycles (pyrimidines, a pyrazole, 2-aminopyridine, theophylline, and an imidazo[1,2-a]pyridine) with BF3-doped montmorillonite (BF3@K10). The new catalyst was characterized by FTIR and 11B NMR spectroscopy, XRD, SEM, and EDS. The developed strategy provides easy and fast access to iodo-, bromo-, and chloro-N-heterocycles under mild conditions. This method was used to synthesize nine new ha...
Source: Synlett - December 18, 2023 Category: Chemistry Authors: El Mansouri, Az-eddine Lachhab, Saida Mehdi, Ahmad Ait-Ali, Mustapha Sanghvi, Yogesh S. Zahouily, M. Lazrek, Hassan B. Tags: letter Source Type: research
Small-Molecule CO2 Donors Accelerate Three-Component Peptide/Protein Bioconjugation with Alkylazides and Phosphines in Ionic Liquids
Synlett DOI: 10.1055/a-2212-7816 Development of chemical modification techniques for peptides and proteins has been facilitated by a set of multicomponent reactions to date. This Letter demonstrates the use of small-molecule CO2 donors to promote reaction efficiency of the coupling of alkylamine on peptides and proteins with azide-derived iminophosphorane and carbon dioxide. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - December 18, 2023 Category: Chemistry Authors: Colella, Brandon M. Ohata, Jun Tags: letter Source Type: research
A Fluorescent Probe for C24 Fatty Acids to Report the Deep Interior of Lipid Bilayers
Synlett DOI: 10.1055/a-2210-1162 To investigate the interdigitation and the resulting fluctuation of lipid chains in the deep part of biomembranes, we aimed to develop a new fluorescent probe based on the well-known trans-parinaric acid (t-PA), but with a tetraene near the end of the C24 chain. The probe, tetracosa-16,18,20,22-tetraenoic acid (TCTEA), synthesized mainly by means of reported strategies, was found to better reflect the behavior of lipids in the deeper interior of bilayers than did t-PA. TCTEA could serve as a useful probe for studying the plasma-membrane dynamics of very-long-chain fatty acids, which have re...
Source: Synlett - December 15, 2023 Category: Chemistry Authors: Umegawa, Yuichi Fukunaga, Shiho Yasuda, Tomokazu Murata, Michio Tags: letter Source Type: research
Evaluating Catalyst Performance in Synthesizing Hydroxyl-Terminated Polybutadiene by Ring-Opening-Metathesis Polymerization
Synlett DOI: 10.1055/s-0043-1763653 Hydroxyl-terminated polybutadiene (HTPB) can be synthesized by ring-opening metathesis polymerization (ROMP) in a one-step process using cyclooctadiene in the presence of a hydroxyl-functionalized chain-transfer agent (CTA). However, previous studies have shown that the presence of primary alcohols can lead to the degradation of some ruthenium catalysts and that the hydroxyl end groups may be converted into aldehydes. Here we compare the performance of five ruthenium-based catalysts — Grubbs first-, second-, and third-generation catalysts (G1, G2, and G3, respectively), Hoveyda–Grubb...
Source: Synlett - December 15, 2023 Category: Chemistry Authors: Su, Gillian A. Reiter, Paul Schulz, Michael D. Tags: letter Source Type: research
A Novel Route towards Bicyclo[1.1.1]pentane Sulfoxides from a Bench-Stable Starting Material
Synlett DOI: 10.1055/a-2210-0893 Bicyclopentanes (BCPs) are non-classical bioisosteres that have gained a lot of interest in drug discovery as non-conjugated rigid hydrocarbons. There has been substantial progress in the synthesis of carbon- and nitrogen-substituted derivatives using [1.1.1]propellane as a precursor, while sulfur-substituted BCPs are rather underdeveloped. This work investigates a new method for the synthesis of BCP-sulfoxides. Herein, a previously reported bench-stable sodium BCP-sulfinate precursor is converted, using a range of aryl and alkyl magnesium bromides, into unsymmetrical BCP-sulfoxides via a c...
Source: Synlett - December 15, 2023 Category: Chemistry Authors: Langer, Lukas S. Stahlberger, Mareen B är, Robin M. Br äse, Stefan Tags: letter Source Type: research
Harnessing the Conformer/Atropisomer-Dependent Photochromism of Diarylethene Photoswitches and Forcing a Diarylethene Atropisomer to Its Configurational Diastereomers with Polymer Mechanochemistry
Synlett DOI: 10.1055/s-0042-1751536 Diarylethenes are an important class of photoswitches that usually exist in interconvertible parallel (photoinert) and antiparallel (photochromic) conformational states. Recent research afforded sterically congested diarylethenes that exist as stable and separable configurational atropisomers. Rational manipulation of stereochemistry is a robust strategy for regulating diarylethene photochemistry. Here, we present a brief account of the conformer/atropisomer-dependent photochromism of diarylethene photoswitches, and we discuss a recent advance at the interface of diarylethene photochemis...
Source: Synlett - December 14, 2023 Category: Chemistry Authors: Zhang, Cijun Fu, Xuancheng Hu, Xiaoran Tags: synpacts Source Type: research
Synthesis of Axially Chiral Bibenzo[g]coumarin Derivatives by Rhodium-Catalyzed Oxidative Annulation of Thiocarbamates
We report a two-step synthesis of binaphthyl-fused chiral bibenzo[g]coumarin derivatives by Rh-catalyzed annulative coupling reaction of BINOL-based thiocarbamates with alkynes. The optical properties of the coupling products were evaluated. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synlett)
Source: Synlett - December 14, 2023 Category: Chemistry Authors: Takishima, Ryo Ghosh, Koushik Nishii, Yuji Miura, Masahiro Tags: letter Source Type: research
Silver Nitrate Catalyzed Sulfonylation of O-Propargyl Alkynes
Synlett DOI: 10.1055/a-2205-5806 The development of new catalytic methods based on lower-cost metals under environmentally friendly conditions is still a challenge. Herein, we report an efficient strategy for the synthesis of vinyl sulfones from O-propargyl alkynes and sodium salts of sulfinic acids using silver nitrate, an inexpensive and readily available catalyst, under air atmosphere using aqueous conditions. The products were obtained in good to moderate yields, and the mechanism of the reaction was also investigated. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:...
Source: Synlett - December 14, 2023 Category: Chemistry Authors: S átiro, Bárbara G. Moura, Igor M. R. Almeida, Cl áudia L. A. Freitas, Queila P. B. Oliveira, Roberta A. Menezes, Paulo H. Tags: letter Source Type: research
Facilitated Synthetic Access to Boronic Acid-Modified Nucleoside Triphosphates and Compatibility with Enzymatic DNA Synthesis
Synlett DOI: 10.1055/a-2212-7704 Decorating nucleic acids with boronic acids can extend the usefulness of oligonucleotide-based tools to the development of medical imaging agents, the promotion of binding of aptamers to markedly more challenging targets, or the detection of (poly)saccharides. However, due to the hygroscopic nature and high intrinsic reactivity of boronic acids, protocols for their introduction into nucleic acids are scarce. Here, we have explored various synthetic routes for the crafting of nucleoside triphosphates equipped with phenylboronic acids. Strain-promoted azide–alkyne cycloaddition appears to b...
Source: Synlett - December 14, 2023 Category: Chemistry Authors: Niogret, Germain R öthlisberger, Pascal Levi-Acobas, Fabienne Bonhomme, Fr édéric Gasser, Gilles Hollenstein, Marcel Tags: letter Source Type: research
Acylative and Silylative Dynamic Kinetic Resolutions of 6-Hydroxy-2H-pyran-3(6H)-one Catalyzed by Chiral Guanidines
Synlett DOI: 10.1055/a-2206-7545 Chiral guanidine-catalyzed acylative and silylative dynamic kinetic resolutions of 6-hydroxy-2H-pyran-3(6H)-one were achieved. We succeeded in developing a non-enzymatic acylative dynamic kinetic resolution of 6-hydroxy-2H-pyran-3(6H)-one with high enantioselectivity, which could be improved by recrystallization. In contrast, the non-enzymatic silylative dynamic kinetic resolution of 6-hydroxy-2H-pyran-3(6H)-one was accomplished with a moderate selectivity for the first time. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of conte...
Source: Synlett - December 14, 2023 Category: Chemistry Authors: Miyazaki, Kanako Nakata, Kenya Tags: letter Source Type: research
