22966-22-9Relevant academic research and scientific papers
Synthesis and structure elucidation of pyrimidobenzimidazoles and fused derivatives III [1,2]. Decahydropyrimido[1,2-a]benzimidazol-2-oles and octahydropyrimido[1,2-a]benzimida-zoles
Goessnitzer, Edith,Wendelin, Winfried
, p. 607 - 624 (2001)
The reaction of racemic trans-hexahydrobenzimidazol-2-amine with three vinylogous ketones under mild conditions was studied. Only in the case of 4-phenyl-3-buten-2-one cycloaddition products could be isolated. According to NMR spectroscopy they consist of mixtures of two of eight possible diastereomers: rac-2β-methyl-4β-phenyl-trans-5aα- and trans-5aβ-decahydropyrimido[1,2-a]benzimidazol-2α-ole. Reaction of the amine with the butenone at higher temperature and with, 2-methyl-1-phenyl-1-penten-3-one, and 4′-chlorochalcone afforded mixtures of two diastereomers each, which turned out as rac-4α-phenyl-trans-5aβ- and trans-5aα-octahydropyrimido[1,2-a]benzimidazoles. Complete structural and stereochemical assignments of the title compounds and their hydrochlorides were established by NMR spectroscopic investigations. The results showed that all investigated cyclization reactions proceeded regioselectively with equal orientation of the components, but not diastereoselectively. Variation of the reaction conditions did influence neither regionor diastereoselectivity.
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
supporting information, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
Enantioselective Stetter Reactions Catalyzed by Bis(amino)cyclopropenylidenes: Important Role for Water as an Additive
Rezazadeh Khalkhali, Mehran,Wilde, Myron M. D.,Gravel, Michel
supporting information, p. 155 - 159 (2021/01/09)
The first highly enantioselective intermolecular Stetter reaction using simple enones is reported. A series of novel chiral BAC structures were designed and prepared. They were tested in the Stetter reaction with simple aldehydes and enones. The products were generated in excellent yields and enantioselectivities (up to 94% ee). Surprisingly, a substoichiometric amount of water was crucial to obtain high enantioselectivities. Chiral BACs were also shown to catalyze 1,6-conjugate addition reactions with paraquinone methides enantioselectively.
Molecular recognition of synthesized halogenated chalcone by calf thymus DNA through multispectroscopic studies and analysis the anti-cancer, anti-bacterial activity of the compounds
Ghosh, Sudipta,Ghosh, Suvranil,Mahato, Sachinta,Majee, Adinath,Mukherjee, Abhijit,Pal, Mahadeb,Sen, Sukanta Kumar,Singh, Bula
, (2021/07/02)
The present study aims to elucidate the anti-cancer, antimicrobial activity of synthesized halogenated chalcones (1f, 1h, 1i) and their molecular interaction with calf thymus DNA. All the three compounds were characterized using different spectroscopic tools like FTIR, NMR. DFT and TDDFT computation were performed to support the structural and electronic parameter of the compounds. UV–vis absorbance, steady-state fluorescence, time-resolved fluorescence, circular dichroism, helix melting, molecular docking study reveals that the compounds (1f, 1h, 1i) actively interact with ctDNA via groove binding mode. The binding constants (Kb) were calculated to be 1.29 × 104, 0.54 × 104 and 0.45 × 104 M?1 respectively for compounds 1f, 1h, 1i. The compounds were cytotoxic to almost every cell line (PC3, HeLa, A549, HCT116) tested, having minimal toxicity in normal NKE cell line, among which PC3 cells were more sensitive with an IC50 value of 10 μM. The values were determined using dose response curve and found between 10 and 49 μM for cancer cells and 70 μM for normal cell. Compounds also cause apoptosis in PC3 cells, which was confirmed by Annexin V-FITC/PI assay. Results showed that 1f, 1h, 1i target DNA, to persuade DNA damage mediated cancer cell death. The inhibition zone was formed in the screening test indicating the anti-bacterial activity of 1f, 1h & 1i against model pathogenic bacteria. So the present communication provides quantitative insight of halo-chalcone based anti-cancerous and antimicrobial molecule involving relevant target nucleic acid, which holds future promise in the development of new therapeutic agents.
Asymmetric transfer hydrogenation of unsaturated ketones; factors influencing 1,4- vs 1,2- regio- and enantioselectivity, and alkene vs alkyne directing effects
Hall, Thomas H.,Adams, Hannah,Vyas, Vijyesh K.,Michael Chu,Wills, Martin
, (2020/12/07)
A detailed study has been completed on the asymmetric transfer hydrogenation (ATH) of a series of enones using Ru(II) catalysts. Electron-rich rings adjacent to the C[dbnd]O group reduce the level of C[dbnd]O reduction compared to C[dbnd]C. The ATH reaction can readily discriminate between double and triple bonds adjacent to ketones, reducing the double bond but leaving a triple bond intact in the major product.
A new method for the synthesis of chalcone derivatives promoted by PPh3/I2under non-alkaline conditions
Xue, Kangsheng,Sun, Guoxiang,Zhang, Yanzhi,Chen, Xubing,Zhou, Yang,Hou, Jinjun,Long, Huali,Zhang, Zijia,Lei, Min,Wu, Wanying
supporting information, p. 625 - 634 (2020/11/23)
A straightforward and general method has been developed for the synthesis of chalcone derivatives by a Claisen-Schmidt reaction in the presence of PPh3/I2 in 1,4-dioxane under reflux temperatures. With the condensation of the aromatic ketone and aldehyde occurring at non-strongly alkaline conditions, our proposed method significantly expands the range of applicable substrates, especially for groups that are unstable under alkaline conditions.
Novel potent and selective DPP-4 inhibitors: Design, synthesis and molecular docking study of dihydropyrimidine phthalimide hybrids
Mourad, Ahmed A. E.,Khodir, Ahmed E.,Saber, Sameh,Mourad, Mai A. E.
, p. 1 - 24 (2021/02/26)
Background: Dipeptidyl peptidase-4 (DPP-4) inhibitors have emerged as antihyperglycemic agents that improve glycemic control in type 2 diabetic patients, either as monotherapy or in combination with other antidiabetic drugs. Methods: A novel series of dihydropyrimidine phthalimide hybrids was synthesized and evaluated for their in vitro and in vivo DPP-4 inhibition activity and selectivity using alogliptin as reference. Oral glucose tolerance test was assessed in type 2 diabetic rats after chronic treatment with the synthesized hybrids ± metformin. Cytotoxicity and antioxidant assays were performed. Additionally, molecular docking study with DPP-4 and structure activity relationship of the novel hybrids were also studied. Results: Among the synthesized hybrids, 10g, 10i, 10e, 10d and 10b had stronger in vitro DPP-4 inhibitory activity than alogliptin. Moreover, an in vivo DPP-4 inhibition assay revealed that 10g and 10i have the strongest and the most extended blood DPP-4 inhibitory activity compared to alogliptin. In type 2 diabetic rats, hybrids 10g, 10i and 10e exhibited better glycemic control than alogliptin, an effect that further supported by metformin combination. Finally, 10j, 10e, 10h and 10d had the highest radical scavenging activity in DPPH assay. Conclusions: Hybrids 10g, 10i and 10e are potent DPP-4 inhibitors which may be beneficial for T2DM treatment.
Heteroleptic copper(I) complexes as energy transfer photocatalysts for the intermolecular [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides
Wu, Qing-An,Ren, Chen-Chao,Chen, Feng,Wang, Tian-Qi,Zhang, Yu,Liu, Xue-Fen,Chen, Jian-Bin,Luo, Shu-Ping
supporting information, (2021/05/10)
The [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides can be effectively catalyzed by heteroleptic copper(I) complexes. The reactions were carried out under mild reaction conditions and the products were obtained in 20–72% yield under visible light irradiation. The copper-based photocatalyst comprised of the rigid phenanthroline ligand with substituents at the 2,9-positions and the 4,7-positions showed high activity in the photodimerization via an energy transfer pathway.
Modular access to 1,2-allenyl ketones based on a photoredox-catalysed radical-polar crossover process
Du, Chan,Fang, Jianghua,Fang, Yewen,Lei, Wan,Li, Yan,Liu, Yongjun
supporting information, p. 8502 - 8506 (2021/10/20)
Herein, a new protocol dealing with the preparation of 1,2-allenyl ketones has been successfully developedviathe reactions of enynes with radicals enabled by dual photoredox/copper catalysis. Based on the results of a deuteration experiment and the competition reaction between cyclopropanation and allenation, the mechanism based on a photoredox-neutral-catalysed radical-polar crossover process has been proposed. Synthetic applications of allenes have also been demonstrated.
Green method for high-selectivity synthesis of chalcone compounds
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Paragraph 0059-0062, (2021/10/02)
Under the condition of air, the water-soluble inorganic weak base is used as a catalyst to catalyze the hydrogen transfer reaction of the propargyl alcohol compound, so that the green synthesis of the high-trans selective chalcone compound is realized. Reaction temperature: 80 - 120 °C and reaction time 12 - 48 hours. To the technical scheme, any transition metal catalyst and ligand do not need to be used, inert gas protection is not needed, no other byproducts are generated, the atom economy 100%, green and environment friendliness are avoided, and the product is a high-selectivity (E)-type product. The reaction conditions are relatively low in requirement. Compared with the prior art, the alkali catalyst is obvious in advantages, and has a certain application prospect in the fields of organic synthesis, biochemistry, medicine and the like.
