Letters in Organic Chemistry最新文献

{"title":"Synthesis and Mesomorphism of New Calamitic Schiff Bases-Ester Possessing Dialkylamino Terminal Substituent","authors":"Lay-Khoon Ong, Sie-Tiong Ha, Guan-Yeow Yeap, Siew-Ling Lee","doi":"10.2174/0115701786295452240327060732","DOIUrl":"https://doi.org/10.2174/0115701786295452240327060732","url":null,"abstract":":: New calamitic liquid crystals, 4-[{[4-(diethylamino)phenyl]methylidene}amino]phenyl 4- alkyloxybenzoate (nEABAA) containing mesogenic core system which made of three phenyl rings were reported. The ester and imine linkages connected the phenyl rings. At one end of the molecule, the core system was attached to an alkyloxy chain with a variable length -(CH2)n- (where n = 2-10, 12, 14, 16 and 18). At the other end of the molecule, the para position of the phenyl ring is bonded to the diethylamino group. The molecular structure of the current compounds was confirmed by using spectroscopic methods. The mesomorphic characteristics of the title compounds were studied by using a differential scanning calorimeter and a polarizing optical microscope attached to a heating stage. Through observation under microscopy, it was found that all synthesized compounds exhibited only a single (nematic) phase. The exhibition of the monophase variance (nematic) in the current compounds is caused by the presence of the diethylamino group that is attached to the terminal position of the benzylideneaniline core system. The diethylamino group has caused the molecular breadth to increase and this results in a weaker overall lateral intermolecular attraction. Subsequently, it depressed the mesophase thermal stability of the compounds. Thermal properties of the current compounds were compared with the earlier reported analogous and the structure-property relationships of the current compounds have been inferred through this comparison.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"45 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140571283","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":"Synthesis of Symmetrical and Unsymmetrical Tetrahydroxybiphenyls and their Evaluation as Amyloid-β Aggregation Inhibitors","authors":"Sarah L. Wicks, Jake A. Roberts, Matthew J. Hurtt, Benjamin P. Hernandez, Jason J. Jones, Andrea L. Taylor, Jessica K. Logan, William J. Schreiber, Mouskudah G. Murray, Brandy L. Crenshaw, Craig B. Stevens, Robin K. Lammi, James M. Hanna Jr.","doi":"10.2174/0115701786286700240322065602","DOIUrl":"https://doi.org/10.2174/0115701786286700240322065602","url":null,"abstract":": Our group recently reported that the polyhydroxy aromatic compound 3,3′,4,4′- biphenyltetrol (2a) is a successful inhibitor of amyloid-β peptide (Aβ) aggregation, decreasing Aβ aggregation by 50 % when present in equimolar concentrations. In the present study, several additional biphenyltetrols were prepared and examined for their in vitro activity against aggregation of Aβ to investigate the effect of the relative positions of hydrogen-bond donors on the aggregation process. Congo red spectral shift assays demonstrated that, of the eight (8) additional biphenyltetrol compounds prepared, three (3) successfully inhibited the association of Aβ monomers, two symmetrical isomers, 2,2′,5,5′-biphenyltetrol (2c), and 2,2′,3,3′-biphenyltetrol (2d), along with one unsymmetrical isomer, 2,3′,4′,5-biphenyltetrol (2g). These results, along with the previously reported results of 2a, strongly suggest that hydroxyl group position affects the ability of the inhibitor to bind to Aβ assemblies, thus impacting inhibitory efficacy.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"26 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140603168","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 Brief Review Depending on the Chemistry of Isatin in Single Pot Technique Towards the Construction of Significant and Valuable Heterocyclic Scaffolds","authors":"Animesh Mondal","doi":"10.2174/0115701786292045240226050222","DOIUrl":"https://doi.org/10.2174/0115701786292045240226050222","url":null,"abstract":":: The term isatin and its derivative-based MCRs have emerged over the years as a versatile, environment-friendly, and very promising platform for the construction of highly enabling bioactive organic scaffolds such as drugs, natural products, pharmaceuticals etc. In the world of recent advancements, the one-pot strategy based on isatin has come to the forefront of synthetic chemistry for the activation of small organic molecules. This present survey touched on the chemistry of isatin employed over the past decade to sketch and for the creation of various types of organic molecules consisting of heterocyclic or spiro-heterocyclic skeletons via one-pot methodology.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"21 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140322259","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":"Preparation and Adsorption Properties of Polymer Particles based on N, N, N', N'-Tetrakis(4-aminophenyl)-1,4-Benzenediamine","authors":"Jian-Yu Huang, Yong Liu, Ting-Hong Huang, Sheng-Zhi Liu, Ai-Ling Wu","doi":"10.2174/0115701786291281240318041709","DOIUrl":"https://doi.org/10.2174/0115701786291281240318041709","url":null,"abstract":": Two polymer particles have been prepared by the reaction of N, N, N', N'-tetrakis(4- aminophenyl)-1,4-benzenediamine, 4, 4-biphenyldialdehyde and isophthalaldehyde, and characterized by SEM, FTIR and XRD. Based on methylene blue as the model pollutant, the adsorption properties of two polymer particles have been observed by using different adsorbent dosages, adsorption times and adsorption temperatures. Experimental data show that the removal rates of methylene blue wastewater are 74 % for polymer A and 68 % for polymer B, and the removal rates are up to 84% for polymer A and 74 % for polymer B after photo-catalytic treatment. All these suggest that the adsorption performance of polymer A is more excellent than that of polymer B. In addition, the methylene blue adsorption of the two Schiff base products conforms to the Freundlich adsorption isothermal model.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"16 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140300190","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":"Antioxidant Activities and Phenolic Composition of Sarcococca saligna Leaves","authors":"Syed Mubashar Sabir, Shabnam Shahida, Alam Zeb, Syed Rizwan Abbas, Muhammad Usman Hameed, Abdallah Shanableh, Muhammad Imran Khan, Djamel Ghernaout, Ramzi Hadj Lajimi, Sarra Elgharbi, Malek Besbes, Noureddine Elboughdiri","doi":"10.2174/0115701786293349240229074809","DOIUrl":"https://doi.org/10.2174/0115701786293349240229074809","url":null,"abstract":": Sarcococca saligna (D. DON) Muel is a vital plant with several steroidal alkaloids and is effective against syphilis, liver diseases, gastrointestinal tract disease, infections, and inflammation. The present study aimed to investigate the in vitro antioxidant activities and phenolic profile of S. saligna. High-performance liquid chromatography (HPLC) analysis has shown the presence of twelve phenolics namely kaempferol-3-O-glucoside, proanthocyanidin B1, quercetin-3-malonylglucoside- 7-glucoside, kaempferol-3-O-sophorotioside, Isorhamnetin-3-O-glucoside-7-Orhamnoside, kaempferolhexoside, 4-O-Caffeoyl-5-O-p-coumaroylquinic acid, 3,4-Di-O-caffeoyl-5- O-feruloylquinic acid, 3,4-Di-O-feruloyl-5-O-caffeoylquinic acid, flavogalloyl-HHDP-gluconic acid (lagerstannin B), 3,4-di-O-caffeoylquinic acid and kaempferol-3-(caffeoyldiglucoside)-7-glucoside. The hot water extract showed the highest anti-lipid peroxidative activities. The IC50 value for 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was 71.5 ± 2.1 μg/mL. The extract could chelate the iron and possess reducing activities on phosphomolybenum assay. It is concluded that extracts of S. saligna are rich in antioxidants and contain essential phytochemicals. objective: The present study was aimed to investigate thein vitro antioxidant activities and phenolic profile of S. saligna. HPLC analysis has shown the presence of twelve phenolics namely kaempferol-3-O-glucoside, proanthocyanidin B1, quercetin-3-malonyl-glucoside-7-glucoside, kaempferol-3-O-sophorotioside,Isorhamnetin-3-O glucoside-7-O-rhamnoside,kaempferolhexoside, 4-O-Caffeoyl-5-O-p-coumaroylquinic acid, 3,4-Di-O-caffeoyl-5-O-feruloylquinic acid, 3,4-Di-O-feruloyl-5-O-caffeoylquinic acid, flavogalloyl-HHDP-gluconic acid (lagerstannin B), 3,4-di-O-caffeoylquinic acid and kaempferol-3-(caffeoyldiglucoside)-7-glucoside. method: The chemical used were 1,10-phenathroline, Thibarbituric acid, TRIS-HCl, amominium molybdate, Iron, sodium nitroprusside. HPLC standards were purchased from Sigma-Aldrich. All the reagents were of analytical grade. Double beam spectrophotometer was used for UV-VIS spectrophotometery. The HPLC system used was Agilent 1260 Infinity HPLC system which consists of quaternary pump, degasser, auto-sampler and diode array detector (DAD). conclusion: The results have shown that S. saligna antioxidant rich extract can be effectively utilized in food and pharmaceutical industries with additional income. However, more detailed understanding of utilization of extract against degenerative diseases is required. There is also need to find out the safety and bioavailability of the plant extract for its use as nutraceutical and as a plant products.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"28 2 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140169727","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":"Polydopamine-Modified Magnetic Nanoparticles (Fe3O4@PDA) for the Copper-Catalyzed Ipso-Hydroxylation of Arylboronic Acids and Subsequent O-Benzylation in Aqueous Media","authors":"Kwang-Beom Lee, Ueon Sang Shin, Seung-Hoi Kim","doi":"10.2174/0115701786294756240305063556","DOIUrl":"https://doi.org/10.2174/0115701786294756240305063556","url":null,"abstract":": A novel advancement has emerged in the realm of catalysis with the development of an innovative method for the ipso-hydroxylation of arylboronic acids. This approach harnessed the power of bio-compatible polydopamine-coated magnetite support (Fe3O4@PDA) in conjunction with a copper salt, forming a heterogeneous catalytic environment. The resulting catalytic system facilitated oxidative hydroxylation under mild aerobic conditions at room temperature in aqueous conditions. This environmentally friendly process allowed for the seamless conversion of diverse arylboronic acids featuring varying electron-withdrawing or electron-donating groups into the corresponding phenols, achieving remarkably high yields. Notably, the versatility of the catalytic system extended to a one-pot tandem O-benzylation of the resultant phenolic intermediates. The additional dimension of the process underscores its efficiency, offering a streamlined route to synthesizing benzyl phenyl ethers with a commendable level of success. The significance of the present catalytic methodology lies not only in its efficacy but also in its eco-friendly attributes, showcasing the potential for sustainable and efficient transformations in organic synthesis.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"24 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154603","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":"Effective Synthesis of N-Alkyl-3-(Indol-3-yl)Pyrazoles from Ag2CO3-Catalyzed Regioselective Aza-Michael Addition of 5-(Indol-3-yl)-1HPyrazoles","authors":"Xue Zhang, Dashuang Luo, Xuemin Niu, Jian Mo, Haifeng Yu, Xiaobo Zhao","doi":"10.2174/0115701786295074240305095904","DOIUrl":"https://doi.org/10.2174/0115701786295074240305095904","url":null,"abstract":": In this study, the synthesis of N-alkyl-3-(indol-3-yl)pyrazoles was carried out from Ag2CO3 catalyzed regioselective aza-Michael addition of 5-(indol-3-yl)-1H-pyrazoles to a, bunsaturated carbonyl compounds. In the presence of 10 mol% of Ag2CO3, the reaction smoothly occurred in dichloroethane (DCE) at 120oC to preferentially afford a series of N-alkyl-3-(indol-3- yl)pyrazoles in high yields with good regioselectivity. It was found that 1-methyl-3-(3-methyl-1Hpyrazol- 5-yl)-2-phenyl-1H-indole, 1-benzyl-3-(3-methyl-1H-pyrazol-5-yl)-1H-indole, a, b-unsaturated ketone, and a, b-unsaturated amide exclusively gave 3-(pyrazol-3-yl)indoles in good yields. This reaction features high regioselectivity, mild reaction conditions, good substrate scope and yields, and a commercially available catalyst. Meanwhile, the reaction was also proven to be quite practical by the gram-scale synthesis of N-alkyl-3-(indol-3-yl)pyrazoles in excellent yields with good regioselectivity.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"90 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140115547","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":"Identification and Synthesis of Oxidative-Degradation and Starting Materials-Attributed Impurities in Lisdexamfetamine Dimesylate","authors":"Suryabhan B. Chaugule, Pradip L. Gole, Siddhesh Haldankar, DVP Kishore, Nilesh L. Bonde, Sandeep A. Kotharkar","doi":"10.2174/0115701786284263240219080226","DOIUrl":"https://doi.org/10.2174/0115701786284263240219080226","url":null,"abstract":": Impurities are an integral part of drug substances, even though they have not been studied in the pharmacological evaluation of the Benefit-Risk (BR) profiles. Hence, understanding their origin and controlling them have prime importance during drug substance development. The structures of some of the impurities in lisdexamfetamine dimesylate, a central nervous system stimulant drug, have been confirmed based on literature and analytical data. The study has been undertaken to evaluate impurities arising from oxidative degradation and impurities due to material attributes. All the listed impurities have been identified, synthesized, and characterized by spectral tools. We have, herein, reported the synthesis of two oxidative degradant impurities, 2-hydroxylisdexamfetamine dimesylate and 4-hydroxylisdexafetamine dimesylate. In addition, chiral isomeric impurities of lisdexamfetamine dimesylate as (S,R), (R,S) and (R,R)-lisdexamfetamine dimesylate have also been reported. These impurities have been identified and synthesized, and a control strategy for mitigating risk in lisdexamfetamine dimesylate is provided.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"44 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140044843","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":"[EMIM] [OAc]: An Efficient Ionic Liquid Medium for the Synthesis of New 4-(furan/pyrrole/thiophene-2-yl)-3, 4-dihydro-1H-chromeno [4,3- d]pyrimidine-2,5-diones and Molecular Docking Studies","authors":"Siva Prakash Pullagura, Arunkumar Thiriveedhi, Venkateswara Rao Battula, Raghunadh Akula, A. Sajeli Begum, Lakshmi Soukya P.S.","doi":"10.2174/0115701786289993240215104621","DOIUrl":"https://doi.org/10.2174/0115701786289993240215104621","url":null,"abstract":": An efficient synthesis of Chromeno[b]pyrimidine derivatives 4 has been achieved by treating 4-hydroxy-2H-chromen-2-one 1, furan-2-carbaldehyde / 1H-pyrrole-2-carbaldehyde/ thiophene-2- carbaldehyde 2, and urea/thiourea 3 at 65-70 °C for 90-120 min using 1-Ethyl-3-methylimidazolium acetate as ionic liquid and medium with good yields 86-90%. This synthetic method has numerous advantages, including high yields, a simple protocol, environmental friendliness, brief reaction times, and mild reaction conditions. Using a catalytically active ionic liquid as the medium eliminates the need for a catalyst and a solvent. In this study, the docking score of the synthesized compounds was found to be between -8 to -9 kcal/mol similar to the co-crystal. Additionally, the compounds maintained their amino acid interactions with Tyr 281 (coagulation protein; 6WV3) and Thr 179 (tubulin polymerization protein; 5LYJ.pdb).","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"6 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140020158","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":"Cholesterol-Based B-Ring 2H-Pyran: Synthesis and Reaction Mechanism by Using Density Functional Theoretical Study","authors":"Priyanka -, Himanshi Kumar, Kamlesh Sharma","doi":"10.2174/0115701786287116240222045947","DOIUrl":"https://doi.org/10.2174/0115701786287116240222045947","url":null,"abstract":": The steroidal B-ring 2H-pyran 2 is synthesized by reacting steroidal B-ring α,β- unsaturated ketone 1 and 2-cyano-N-methylacetamide by refluxing for 18 h in methanol in the presence of a catalyst, i.e., chitosan. The product is obtained with a yield of 67%. The structure of the final product 2 is confirmed by utilizing IR, Mass, 13C and 1H NMR spectra. The reaction mechanism of the steroidal pyran ring formation is explored in this paper. The reaction pathway is described by using FMO analysis and relative energies of starting material, intermediate, and transition states, calculated by using the theoretical method, i.e., DFT with B3LYP/6-31G(d). It is found that two intermediates are formed throughout the reaction, which undergo a respective transition state (TS1 and TS2). The energy barrier of each step of the reaction is also calculated. It is also concluded that the reaction is endothermic. The green synthetic method reported in this study would be very useful for the synthetic and medicinal chemists involved in the synthesis of biologically important pyran ring-containing heterocyclic compounds.","PeriodicalId":18116,"journal":{"name":"Letters in Organic Chemistry","volume":"109 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140018664","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}