{"title":"Convenient synthesis of O-alkylated/N-acylated polyhydroxyazepane based compounds for modulating MD-2-TLR4 complex formation","authors":"Sumit , Sudipta Nandi , Indrapal Singh Aidhen","doi":"10.1016/j.tetlet.2024.155388","DOIUrl":"10.1016/j.tetlet.2024.155388","url":null,"abstract":"<div><div>Toll-like receptor 4 (TLR4) is a critical component of the innate immune system, recognizing lipopolysaccharide (LPS) from Gram-negative bacteria and triggering immune responses. The activation of TLR4 involves several key steps, including interactions with LPS-binding protein (LBP), CD14, and myeloid differentiation protein 2 (MD-2), culminating in the formation of the (LPS.MD-2 TLR4)<sub>2</sub> complex. Structural insights show that LPS acyl chains insert into the hydrophobic pocket of MD-2, driving TLR4 activation. Inspired by this understanding, numerous natural and synthetic compounds have been developed to inhibit TLR4 by targeting the MD-2/TLR4 complex. Eritoran <strong>1</strong>, is one such illustration. The conformational flexibility of azepane architecture inspired us to visualize <em>O</em>-alkylated/<em>N</em>-acylated polyhydroxyazepane-based compounds toward this objective. The docking studies and molecular simulation studies supported the rationale. Synthesis of <em>O</em>-alkylated/<em>N</em>-acylated polyhydroxyazepane-based compounds <strong>2</strong>-<strong>4</strong> (<strong>a</strong>-<strong>h</strong>) through a key building block is described herein.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155388"},"PeriodicalIF":1.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A practical synthesis of Cbz protected (1R,2R) and (1S,2S) 2-hydroxy-cyclobutylamines","authors":"Can Jin, Yilin Wang, Xiangsheng Xu, Xiaoqing Li","doi":"10.1016/j.tetlet.2024.155391","DOIUrl":"10.1016/j.tetlet.2024.155391","url":null,"abstract":"<div><div><em>(1R,2R)</em> and <em>(1S,2S)</em> 2-hydroxy-cyclobutylamines are important substructures in a range of bio-active molecules and pharmaceutical candidates. In view of the potential safety issues and the low reaction efficiency associated with the earlier published synthetic process, which relies on Curtius rearrangement for the synthesis of 2-amino-cyclobutanone intermediate, a more practical and efficient process to prepare <em>(1R,2R)</em> and <em>(1S,2S)</em> 2-hydroxy-cyclobutylamines using readily available <em>N-</em>Cbz-2-amino-cyclobutanone was developed. Cbz protected <em>(1R,2R)</em> 2-hydroxy-cyclobutylamine could be synthesized in 14 % yield over 5 steps.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155391"},"PeriodicalIF":1.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Efficient synthesis of highly substituted benzoselenazole derivatives through the one-pot, multi-step Ullmann coupling reaction","authors":"Manijeh Nematpour","doi":"10.1016/j.tetlet.2024.155387","DOIUrl":"10.1016/j.tetlet.2024.155387","url":null,"abstract":"<div><div>In this research, the simple and efficient method for the synthesis of highly substituted benzoselenazole derivatives using the one-pot, multi-step Ullman coupling reaction of acyl isoselenocyanate-nitro compounds adducts and dihalobenzene in the vicinity of K<sub>2</sub>CO<sub>3</sub> as a base, copper iodide, at room temperature, and in MeCN solvent has been done successfully. The use of simple and available raw materials, mild copper catalytic reaction conditions, easy purification with the help of solvent, and finally the synthesis of 16 new compounds from the benzoselenazoles family are notable features of this protocol.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155387"},"PeriodicalIF":1.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
He Wu, Yong Wang, Guangguang Yang, Karuppu Selvaraj, Gang Chen
{"title":"Biomimetic oxidation of tetracycline and derivatives at C11a","authors":"He Wu, Yong Wang, Guangguang Yang, Karuppu Selvaraj, Gang Chen","doi":"10.1016/j.tetlet.2024.155366","DOIUrl":"10.1016/j.tetlet.2024.155366","url":null,"abstract":"<div><div>Tetracycline destructases (TDases), a type of TC-inactivating enzymes, inactivate all known TC antibiotics by C11a oxidation, which is considered as a clinical threat. To provide more information on this enzymatic inactivation and oxygenated TCs, we report here a chemical oxidation of Tetracycline and its derivatives at the C11a position using <em>m</em>-CPBA with additives via biomimetic pathways. The structures of the oxygen-containing TCs (<strong>2h, 2i</strong>) were confirmed by X-ray analysis, and further transformations were performed with oxygen-containing TCs (<strong>2e</strong>, <strong>2i</strong>).</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155366"},"PeriodicalIF":1.5,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun Ma , Huali Wang , Qingyu Meng , Haoyue Wang , Fangyi Li , Zheng Li
{"title":"Synthesis of 2,4,5-vinylic-trisubstituted oxazoles via a Palladium-catalyzed cascade coupling reaction","authors":"Jun Ma , Huali Wang , Qingyu Meng , Haoyue Wang , Fangyi Li , Zheng Li","doi":"10.1016/j.tetlet.2024.155373","DOIUrl":"10.1016/j.tetlet.2024.155373","url":null,"abstract":"<div><div>A novel one-step synthesis of valuable 2,4,5-vinylic-trisubstituted oxazoles is described. This reaction, utilizing readily available β,β-dibrominated secondary enamides and terminal alkenes as starting materials, occurs via a ligand-free Palladium-catalyzed cascade intramolecular C<img>O coupling/intermolecular Heck reaction.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"153 ","pages":"Article 155373"},"PeriodicalIF":1.5,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sudhir R. Ingale , Ramavath Vinodkumar , Ravindar Kontham
{"title":"The first enantioselective total synthesis of the eremophilane-type sesquiterpenoid (−)-peniroqueforin C","authors":"Sudhir R. Ingale , Ramavath Vinodkumar , Ravindar Kontham","doi":"10.1016/j.tetlet.2024.155386","DOIUrl":"10.1016/j.tetlet.2024.155386","url":null,"abstract":"<div><div>Herein, we report the first stereoselective total synthesis of the eremophilane-type sesquiterpenoid (−)-peniroqueforin C using a chiral-pool strategy. This synthetic route features the use of readily available (<em>S</em>)-(+)-carvone as a chiral building block, Robinson annulation to construct the decalin system, substrate-controlled stereoselective methylation, single-step annulative construction of a tricyclic <em>γ</em>-ylidene-butenolide with concomitant alkene transposition, and direct lactone-to-lactam conversion as key transformations.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155386"},"PeriodicalIF":1.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Palladium-catalyzed cycloisomerization of thiocarbamates with consecutive formation of quaternary carbon and sulfide","authors":"Hyu Kumazawa, Masahisa Nakada","doi":"10.1016/j.tetlet.2024.155384","DOIUrl":"10.1016/j.tetlet.2024.155384","url":null,"abstract":"<div><div>The Pd-catalyzed cycloisomerization of thiocarbamates with consecutive formation of a quaternary carbon and a sulfide is described. This Pd-catalyzed cascade reaction occurred with both alkylthiocarbamates and arylthiocarbamates, and arylthiocarbamates reacted faster than alkylthiocarbamates. The Pd-catalyzed cycloisomerization can be applied to phenylene- and alkylene-tethered substrates, and thiocarbamate was found to be less reactive than carbamimidothioate. The Pd-catalyzed cycloisomerization can be used to form bridged rings and is expected to be useful for ring construction of nitrogen-containing polycyclic natural products.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155384"},"PeriodicalIF":1.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amit Patwa, Chayanika Pegu, Bidisha Paroi, Nitin T. Patil
{"title":"Enantioselective gold/enzyme dual catalysis","authors":"Amit Patwa, Chayanika Pegu, Bidisha Paroi, Nitin T. Patil","doi":"10.1016/j.tetlet.2024.155382","DOIUrl":"10.1016/j.tetlet.2024.155382","url":null,"abstract":"<div><div>Over the decades, enantioselective metal/enzyme dual catalysis has emerged as a dynamic area of research in asymmetric synthesis. By leveraging the unique reactivities of metal/enzyme dual catalysis, numerous transformations have been developed, primarily relying on metals such as Pd, Ru, Ir, Fe and Au. Among all transition metals, gold stands out as the catalyst of choice due to its soft <em>π</em>-acidic nature. The <em>π</em>-activation reactivities of gold catalysts have been strategically integrated with enzyme catalysis, thereby leading to highly enantioselective transformations that are unattainable <em>via</em> a single catalyst alone. This review endeavors to provide an overview of the advancements in enantioselective gold/enzyme dual catalysis.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"154 ","pages":"Article 155382"},"PeriodicalIF":1.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dan Yang , Beichen Wang , Zihao Song , Jiahui Tang , Ning Wang , Jun Wang , Yu Wang , Yi-Ming Li
{"title":"One-step solid-phase synthesis of activated cell-penetrating peptides for cytosolic delivery of protein","authors":"Dan Yang , Beichen Wang , Zihao Song , Jiahui Tang , Ning Wang , Jun Wang , Yu Wang , Yi-Ming Li","doi":"10.1016/j.tetlet.2024.155385","DOIUrl":"10.1016/j.tetlet.2024.155385","url":null,"abstract":"<div><div>Cell-penetrating peptides (CPP) enable to deliver large biomolecules (proteins, peptides, oligonucleotides, etc.) into cells. An important step for the conjugation of CPPs to target proteins is the acquisition of activated CPPs, however, it requires a multi-step isolation and purification process. Here, we report a facile strategy for the synthesis of activated cell-penetrating peptides via a one-step solid-phase synthesis through the reaction of 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) with CPP on resins, which can then be treated with a TFA cocktails to directly obtain activated CPP (TNB-CPP). Using this strategy, we successfully obtained activated cyclic cell-penetrating deca-arginine peptide (TNB-cR10) and activated Tat (TNB-Tat) and efficient cytosolic delivery of ubiquitin (Ub) can be achieved by linking it to these CPPs.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"153 ","pages":"Article 155385"},"PeriodicalIF":1.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Candida antarctica lipase B catalyzed condensation reactions: Water mediated chemo-enzymatic synthesis of different heterocycles","authors":"Satyaveni Malasala , Anusha Polomani , Jitendra Gour , Srinivas Nanduri","doi":"10.1016/j.tetlet.2024.155371","DOIUrl":"10.1016/j.tetlet.2024.155371","url":null,"abstract":"<div><div>A water-mediated, chemoenzymatic reaction has been developed for synthesizing various heterocycles. This reported method is compatible with various condensation reactions and multi-component reactions, such as the Biginelli reaction. It offers direct access to benzothiazole, benzimidazole, benzoxazole, quinazolinone, and pyrimidines using straightforward reaction conditions, adhering to green chemistry principles.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"153 ","pages":"Article 155371"},"PeriodicalIF":1.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}