- Efficient 1H nuclear magnetic resonance method for improved quality control analyses of Ginkgo constituents
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We developed an analytical method using 1H nuclear magnetic resonance (NMR) spectrometry to resolve analytical problems with Ginkgo. After a simple hydrolysis step, an NMR analysis of the terpene trilactone H-12 signals and the flavonol aglycone H-2′ (or H-2′/6′ for kaempferol) signals was performed. By comparing the solvent effects on the resolution of these signals, methanol-d4-benzene-d6 (65:35) was selected as the optimal 1H NMR solvent. The amounts of terpene lactones and flavonol aglycones in various commercial Ginkgo products and Ginkgo leaves were determined. This newly developed 1H NMR method enables the simultaneous analysis of terpene trilactones and flavonols and allows simple, rapid quantification of these compounds in pharmaceutical Ginkgo preparations.
- Li, Chia-Ying,Lin, Chun-Hua,Wu, Chia-Che,Lee, Kuo-Hsiung,Wu, Tian-Shung
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Read Online
- Scandium trifluoromethanesulphonate as an active catalyst in the decarbonylation of aromatic aldehydes
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Scandium trifluoromethanesulphonate efficiently catalyzes the decarbonylation of 2,4,6-trimethoxybenzaldehyde (1) which, on heating in MeOH solution, is deformylated neatly and completely in a few minutes, yielding 1,3,5 trimethoxybenzene and methyl formate. The reaction was studied by UV and NMR spectroscopy, which gave evidence for the reaction mechanism. Aromatic aldehydes less electron rich than 1 were decarbonylated more sluggishly. The unique catalytic properties of Sc(OTf)3 were compared with other non transition metal triflates.
- Castellani, Carla Bisi,Carugo, Oliviero,Giusti, Manuel,Leopizzi, Claudia,Perotti, Angelo,Invernizzi, Anna Gamba,Vidari, Giovanni
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Read Online
- Phloroglucinol derivatives as anti-tumor agents: synthesis, biological activity evaluation and molecular docking studies
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Phloroglucinol compounds isolated from Dryopteris fragrans (L.) Schott showed a variety of biological activities, such as anticancer and anti-inflammatory. In this study, we have made a number of modifications around the scaffold of phloroglucinol and synthesized phloroglucinol derivatives A1–A9, B1–B9, and C1–C3. We synthesized these compounds and investigated their effect on four human cancer cell lines (A-549, MCF-7, Hela, HepG2 cell lines) via MTT assay in vitro. The results revealed that all compounds exhibited certain antiproliferative activities on cancer cell lines and excellent inhibitory effects on MCF-7, in which compound C2 was the best with the IC50 value of 18.49 μM, exceeding that of 5-fluorouracil. Moreover, the cell apoptosis test showed that compound C2 induced apoptosis in a concentration-dependent manner. Furthermore, the results of molecular docking analysis explained the probable interaction between the active compounds and active sites of target protein 4I22 and 1OG5. [Figure not available: see fulltext.]
- Jin, Xiaobao,Lai, Qingfu,Lai, Weihong,Li, Ming,Ye, Lianbao,Zhang, Fuli
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- Methylation with Dimethyl Carbonate/Dimethyl Sulfide Mixtures: An Integrated Process without Addition of Acid/Base and Formation of Residual Salts
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Dimethyl sulfide, a major byproduct of the Kraft pulping process, was used as an inexpensive and sustainable catalyst/co-reagent (methyl donor) for various methylations with dimethyl carbonate (as both reagent and solvent), which afforded excellent yields of O-methylated phenols and benzoic acids, and mono-C-methylated arylacetonitriles. Furthermore, these products could be isolated using a remarkably straightforward workup and purification procedure, realized by dimethyl sulfide‘s neutral and distillable nature and the absence of residual salts. The likely mechanisms of these methylations were elucidated using experimental and theoretical methods, which revealed that the key step involves the generation of a highly reactive trimethylsulfonium methylcarbonate intermediate. The phenol methylation process represents a rare example of a Williamson-type reaction that occurs without the addition of a Br?nsted base.
- Chan, Bun,Lui, Matthew Y.,Lui, Yuen Wai
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- Preparation method of trimethylphloroglucinol
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The invention discloses a preparation method of trimethylphloroglucinol. According to the invention, phloroglucinol is taken as a raw material, and sulfuric acid is adopted to catalyze a first-step reaction, so operation is simpler and more convenient, reaction byproducts are reduced, and damage to production equipment is reduced; and a reaction product obtained in the first-step reaction and dimethyl carbonate are subjected to a second-step methylation reaction, and dimethyl carbonate is non-toxic and non-corrosive, so production safety is greatly improved, the method is green and environment-friendly, and the quality and yield of a final finished product are improved. The method solves the problem of low safety in the production process of existing trimethylphloroglucinol preparation methods, avoids the use of strong corrosive reagents such as hydrochloric acid, and adopts dimethyl carbonate to replace a highly toxic reagent, namely dimethyl sulfate.
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Paragraph 0029-0043
(2021/09/21)
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- Catalytic SNAr Hydroxylation and Alkoxylation of Aryl Fluorides
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Nucleophilic aromatic substitution (SNAr) is a powerful strategy for incorporating a heteroatom into an aromatic ring by displacement of a leaving group with a nucleophile, but this method is limited to electron-deficient arenes. We have now established a reliable method for accessing phenols and phenyl alkyl ethers via catalytic SNAr reactions. The method is applicable to a broad array of electron-rich and neutral aryl fluorides, which are inert under classical SNAr conditions. Although the mechanism of SNAr reactions involving metal arene complexes is hypothesized to involve a stepwise pathway (addition followed by elimination), experimental data that support this hypothesis is still under exploration. Mechanistic studies and DFT calculations suggest either a stepwise or stepwise-like energy profile. Notably, we isolated a rhodium η5-cyclohexadienyl complex intermediate with an sp3-hybridized carbon bearing both a nucleophile and a leaving group.
- Kang, Qi-Kai,Li, Ke,Li, Yuntong,Lin, Yunzhi,Shi, Hang,Xu, Lun
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supporting information
p. 20391 - 20399
(2021/08/13)
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- Facile C-S Bond Cleavage of Aryl Sulfoxides Promoted by Bronsted Acid
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A method for the Bronsted acid promoted desulfination of aryl sulfoxides is presented. In the presence of a thiol, electron-rich sulfoxides undergo C-S bond cleavage to give the corresponding protodesulfinated arenes and disulfides.
- Brutiu, Bogdan R.,Klose, Immo,Maulide, Nuno
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supporting information
p. 488 - 490
(2021/03/09)
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- Synthesis method of high-purity phloroglucinol compound
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The invention discloses a one-step chemical catalytic synthesis method of high-purity phloroglucinol by taking 3,5-dichlorophenol as a starting material and taking strong base and a catalyst as auxiliary materials. Through the method, the phloroglucinol compound with high molar yield, high purity and low cost can be effectively synthesized.
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Paragraph 0018
(2021/06/09)
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- Synthesis of fluorine-containing prenylated benzophenones
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In this study, an effective route to synthesize fluorine-containing prenylated benzophenones was developed. Friedel–Crafts acylation and electrophilic aromatic substitution reactions were the key reactions of this synthesis to achieve these fluorinated prenylated benzophenones. The use of DBU in the prenylation step achieved only the C-prenylated benzophenones, whereas K2CO3 produced the C- and O-prenylated benzophenones.
- Mzozoyana, Vuyisa,van Heerden, Fanie R.
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supporting information
p. 2226 - 2235
(2020/07/09)
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- Development of a novel nitric oxide (NO) production inhibitor with potential therapeutic effect on chronic inflammation
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Inflammation is a complex biological response to stimuli. Activated macrophages induced excessively release of pro-inflammatory cytokines and mediators such as endogenous radical nitric oxide (NO) play a significant role in the progression of multiple inflammatory diseases. Both natural and synthetic chalcones possess a wide range of bioactivities. In this work, thirty-nine chalcones and three related compounds, including several novel ones, based on bioactive kava chalcones were designed, synthesized and their inhibitory effects on NO production in RAW 264.7 cells were evaluated. The novel compound (E)-1-(2′-hydroxy-4′,6′-dimethoxyphenyl)-3-(3-methoxy-4-(3-morpholinopropoxy)phenyl)prop-2-en-1-one (53) exhibited a better inhibitory activity (84.0%) on NO production at 10 μM (IC50 = 6.4 μM) with the lowest cytotoxicity (IC50 > 80 μM) among the tested compounds. Besides, western blot analysis indicated that compound 53 was a potent down-regulator of inducible nitric oxide synthase (iNOS) protein. Docking study revealed that compound 53 also can dock into the active site of iNOS. Furthermore, at the dose of 10 mg/kg/day, compound 53 could both significantly suppress the progression of inflammation on collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) models. In addition, the structure-activity relationship (SAR) of the kava chalcones based analogs was also depicted.
- Chen, Lijuan,Fan, Tiantian,Lei, Xiangui,Teichmann, Alexander Tobias,Wang, Amu,Wang, Chao,Wei, Zhe,Wieland, Frank Heinrich,Yang, Youzhe,Yin, Jinxiang,Zhou, Li,Zhu, Yue
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- Reversible Insertion of Carbon Dioxide at Phosphine Sulfonamido PdII-Aryl Complexes
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Phosphine sulfonamido Pd(II) complexes bearing p-anisyl ([(P,N)Pd(4-OMe-C6H4)L]; L = C5H5N, 5-py; L = OS(CH3)2, 5-dmso) or carboxylato ([(P,N)Pd(OOCR)], 1-X: R = 4-OMe-C6H4, 1-pAn; R = tBu, 1-Piv; R = C6H5, 1-Ph) ligands were synthesized and their structures and dynamic behaviors were characterized. The compound 5-dmso can effectively be converted to 1-pAn by migratory insertion of carbon dioxide into the Pd-aryl bond with precoordination of the CO2 molecule. Additionally, carboxylato-substituted compounds 1-X can serve as catalysts for protodecarboxylation reactions of bis-o-OMe-substituted carboxylic acids at room temperature without the need for an external proton source. Stoichiometric decarboxylative coupling of these acids with styrene selectively yields 1,1-diarylated olefins.
- Voit, Gregor,Jenthra, Sangeth,H?lscher, Markus,Weyhermüller, Thomas,Leitner, Walter
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p. 4465 - 4473
(2020/12/23)
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- SYNTHESIS OF MORIN AND MORIN DERIVATIVES
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The invention relates to a method for directly producing morin derivatives and high-purity morin of formula (I). The invention also relates to morin derivatives and high-purity morin that can be obtained using the claimed method.
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Paragraph 0031; 0033
(2020/11/24)
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- Catalytic hydrodebromination of aryl bromides by cobalt tetra-butyl porphyrin complexes with EtOH
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Hydrodebromination of aryl bromides catalyzed by electron rich and sterically unhindered cobalt 5,10,15,20-tetrabutylporphyrin was achieved at mild conditions in good yields employing EtOH as the hydrogen source. The catalytic efficiency was enhanced compared with previously reported by cobalt tetra-aryl porphyrin catalysts. A revised mechanism of single electron transfer was proposed.
- Chen, Chen,Zuo, Huiping,Chan, Kin Shing
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p. 510 - 517
(2019/01/04)
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- Synthetic method of buflomedil hydrochloride intermediate 1, 3, 5-trimethoxybenzene
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The invention discloses a synthetic method of buflomedil hydrochloride intermediate 1, 3, 5-trimethoxybenzene. Phenyl trihalide and methyl alcohol are reacted under the action of a catalyst to obtainthe 1, 3, 5-trimethoxybenzene. A reaction process includes the steps: 1) uniformly mixing the methyl alcohol and the catalyst, leading in protective gas, controlling the pressure to reach 5-8 barometric pressures, controlling the temperature to reach 120-145 DEG C, keeping the temperature for 20-35 minutes, dripping solution B formed by the phenyl trihalide and a solvent A, controlling the dripping time of the solution B to reach 35-50 minutes, dripping acid-binding agents after the solution B is completely added, controlling the dripping time of the acid-binding agents to reach 5-12 minutes,heating mixture to reach the temperature of 155-170 DEG C, increasing the pressure to reach 9-12 barometric pressures after the acid-binding agents are completely added, and continuing to perform reaction for 7-13 hours to complete reaction; 2) cooling a system, removing solid in a filtered manner, adding filter liquid into water with the volume of 3-6 times, extracting mixture by a solvent C, drying extracts by a drying agent, concentrating and evaporating the solvent to obtain a product. According to the synthetic method, highly toxic and harmful substances are omitted, and the method has high yield.
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Paragraph 0033-0038; 0039-0044; 0045-0050
(2019/03/08)
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- Synthesis of new C-dimethylated chalcones as potent antitubercular agents
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A new class of C-dimethylated-chalcones (9a–q) were synthesized by using 2-hydroxy-3,5-dimethyl-4,6-dimethoxy acetophenone as a key intermediate. The compounds were screened for anti-tubercular activity against Mycobacterium tuberculosis strain (H37Rv) by Microplate Alamar Blue assay (MABA) method at a concentration of 100–0.8 μg/mL. The chalcones, 9a, 9b, 9c, 9k, 9o, and 9p were found to have higher antitubercular activity than the standard drugs, while the remaining compounds showed moderate activity. The antitubercular activity of the chalcones, 9b (MIC90 = 3.98 μM) and 9o (MIC90 = 3.84 μM) was found to be more than two-fold more active than the standard drugs, streptomycin (MIC90 = 10.75 μM) and ciprofloxacin (MIC90 = 9.43 μM), while their antitubercular activity was found to be more than six-fold more active than pyrazinamide (MIC90 = 25.38 μM). Further, the molecular docking studies employing Mycobacterium tuberculosis protein tyrosine phosphatase (MtbPtp) was carried out to observe docking scores.
- Anandam, Rambabu,Jadav, Surender Singh,Ala, Vasu Babu,Ahsan, Mohamed Jawed,Bollikolla, Hari Babu
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p. 1690 - 1704
(2018/05/14)
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- Synthesis of structurally diverse biflavonoids
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Synthetic biflavonoids are associated with interesting biological activities, yet they remain poorly explored within drug discovery. Recent years have witnessed a growing interest in synthetic approaches that can provide access to structurally novel biflavonoids so that the biological usefulness of this compound class can be more fully investigated. Herein, we report upon the exploration of strategies based around Suzuki-Miyaura cross-coupling and alcohol methylenation for the synthesis of two classes of biflavonoids: (i) rare ‘hybrid’ derivatives containing flavonoid monomers belonging to different subclasses, and (ii) homodimeric compounds in which the two flavonoid monomers are linked by a methylenedioxy group. Application of these strategies enabled the preparation of a structurally diverse collection of novel biflavonoids from readily-available starting materials, thereby facilitating the probing of uncharted regions of biologically interesting chemical space.
- Sum, Tze Jing,Sum, Tze Han,Galloway, Warren R.J.D.,Twigg, David G.,Ciardiello, Joe J.,Spring, David R.
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supporting information
p. 5089 - 5101
(2018/05/23)
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- Efficient synthesis of α-substituted-α-arylmethyl phosphonates using trichloroacetimidate C–C coupling method
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A simple convenient protocol for the synthesis of diethyl α,α-diaryl methylphosphonate derivatives 5a-f, 6b-f, 7a-f and 8a-f, diethyl α-alkenyl α-aryl methylphosphonates 9a-d and 10a-d and α-(oxoalkyl) α-aryl methylphosphonate 11a-d and 12a-d is described. Trichloroacetimidates 3a-d were treated with activated arenes, styrene, allyltrimethylsilane or silylenol ethers C-nucleophiles in the presence TMSOTf to afford the desired products in good yields and short reaction time.
- Fathalla, Walid,Pazdera, Pavel,El-Rayes, Samir,Ali, Ibrahim.A.I.
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p. 1681 - 1691
(2018/03/01)
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- B(C6F5)3-Catalyzed Regioselective Deuteration of Electron-Rich Aromatic and Heteroaromatic Compounds
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Deuterium labeled compounds find widespread application in life science. Herein, the deuteration of electron-rich (hetero)aromatic compounds employing B(C6F5)3 as the catalyst and D2O as the deuterium source is reported. This protocol is highly efficient, simply manipulated, and successfully applied in the deuteration of 23 substrates including natural neurotransmitter-like melatonin. It is assumed that the weakening of the O-D bond ultimately results in the formation of electrophilic D+.
- Li, Wu,Wang, Ming-Ming,Hu, Yuya,Werner, Thomas
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supporting information
p. 5768 - 5771
(2017/11/10)
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- Synthesis of 3-geranyl- and 3-prenyl-2,4,6-trihydroxybenzophenone
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Biologically active phenyl[3-(3,7-dimethyl-2,6-octadienyl)-2,4,6-trihydroxyphenyl]methanone (2) and phenyl[2,4,6-trihydroxy-3-(3-methyl-2-butenyl)phenyl]methanone (3) were synthesized by an efficient and convenient synthetic sequence. The reaction steps of this synthesis included methylation, Friedel-Crafts acylation, demethylation and geranylation steps.
- Mzozoyana, Vuyisa,van Heerden, Fanie R.
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supporting information
p. 599 - 603
(2017/03/15)
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- Fluorination of supramolecular liquid crystals-tuning tool and analytical probe
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A study on the impact of fluorination on the properties of photo-responsive hydrogen-bonded liquid crystals is reported. The chosen modular approach allows for efficient screening of a variety of hydrogen-bonded assemblies. Tremendous effects on the mesophase stabilization and morphology are described. In addition, the fluorine substituents are used as analytical probes for 19F solid-state NMR studies, providing insight into the molecular alignment of the assemblies.
- Spengler, Matthias,Dong, Ronald Y.,Michal, Carl A.,Pfletscher, Michael,Giese, Michael
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supporting information
p. 2235 - 2239
(2017/03/14)
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- Transition metal-free protodecarboxylation of electron rich aromatic acids under mild conditions
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A mild and practical method for the transition metal-free protodecarboxylation of aromatic acids using readily available and safe sodium persulfate as initiator was described. This environment-friendly decarboxylation approach was performed at 60 °C in ethanol and could easily scale up to the gram level with a good yield. In Particular, the tandem reactions of decarboxylation and halogenation were achieved by the addition of the corresponding halogenating reagents to the reaction system.
- Fang, Jingxian,Wang, Dangui,Deng, Guo-Jun,Gong, Hang
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p. 4503 - 4506
(2017/10/30)
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- An alternative synthesis of 2,6-dimethoxyl-1,4-benzoquinone
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An economic four-step synthesis of 2,6-dimethoxy-1,4-benzoquinone was achieved in 68 % overall yield starting from aniline. The reaction sequence involved conversion to1,3,5-tribromoaniline, deamination, methoxylation, and oxidation. The procedure is operationally simple and amenable to scale-up production.
- Wang, Qian,Yang, Jian,Zheng, Yang,Liao, Xiali
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p. 193 - 194
(2017/06/20)
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- Are of a kind of preparation are connected and method
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The invention belongs to the field of marine chemical industry medicine intermediates, and particularly relates to a method for preparing pyrogallol and phloroglucinol, wherein the preparation route that trimethoxybenzaldehyde is subjected to catalysis decarbonylation under a hydrogen atmosphere is adopted, the modified raney nickel is adopted as a catalyst to carry out a catalysis decarbonylation reaction in a solvent, the modified raney nickel is subjected to bulk phase and surface modification based on the conventional raney nickel preparation method, the modified component is one or a plurality of materials selected from Mn, Fe, Cr, Mo, Ti and W, and the modified component content (wt) is 0.5-10 wt%. The method has characteristics of environmental protection, easy operation, wide raw material source, short reaction step, simple catalyst preparation and capability of being repeatedly applied multiple times, and is suitable for industrialization.
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Paragraph 0038; 0039
(2017/02/24)
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- Multi-substituted aromatic diketone compound and its preparation method and application (by machine translation)
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The invention of the formula (I) of the said multi-substituted aromatic diketone compound and its preparation and application. Formula (I) in R 1 formula (I-1), type (I-2) or a formula (I-3) substituent, R 2 to-H, -F, -Cl, -Br, -CH 3 or-OCH 3. When the R 1 formula (I-1) time, the method of the invention is to 2,4-di-hydroxy acetophenone as raw materials, and the bromine acetaldehyde compressed ethylene glycol reaction to obtain 1 - (4 - (2,2-methoxyethoxy) - 2-hydroxy-phenyl) ethanone, then the ring, and aryl acyl chloride reaction, the rearranged under alkaline conditions to obtain multi-substituted aromatic diketone compound. When the R 1 (I-2) for the time, the method of this invention and R 1 (I-1) is basically the same as the. When the R 1 formula (I-3) time, the method of the invention is to to phloroglucinol as raw materials, by methylation of 1, 3, 5-trimethoxy, by reaction with acetyl chloride 1,1 ˊ - (2-hydroxy -4,6-dimethoxy -1,3-phenylene) b ethanone, then the aryl acyl chloride reaction, the rearranged under alkaline conditions to obtain multi-substituted aromatic diketone compound. Compound of the present invention, to HIV-1 integrase inhibiting effect. (by machine translation)
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Paragraph 0089-0093
(2017/02/28)
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- Masked N-Heterocyclic Carbene-Catalyzed Alkylation of Phenols with Organic Carbonates
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An easily prepared masked N-heterocyclic carbene, 1,3-dimethylimidazolium-2-carboxylate (DMI-CO2), was investigated as a “green” and inexpensive organocatalyst for the alkylation of phenols. The process made use of various low-toxicity and renewable alkylating agents, such as dimethyl- and diethyl carbonate, in a focused microwave reactor. DMI-CO2 was found to be a very active catalyst and excellent yields of a range of aryl alkyl ethers were obtained under relatively benign conditions. The observed difference in the conversion behavior of phenol methylation, in the presence of either the carbene or 1,8-diazabicycloundec-7-ene (DBU) catalyst, was rationalized on the basis of mechanistic investigations. The primary mode of action for the N-heterocyclic carbene is nucleophilic catalysis. Activation of the dialkyl carbonate electrophile results in concomitant evolution of an organo-soluble alkoxide, which deprotonates the phenolic starting material. In contrast, DBU is initially protonated by the phenol and thus consumed. Subsequent regeneration and participation in nucleophilic catalysis only becomes significant after some phenolate alkylation occurs.
- Lui, Matthew Y.,Yuen, Alexander K. L.,Masters, Anthony F.,Maschmeyer, Thomas
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p. 2312 - 2316
(2016/10/24)
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- INTRODUCTION OF ALKYL SUBSTITUENTS TO AROMATIC COMPOUNDS
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Novel selective synthesis route to introduce primary alkyl groups on aromatic compounds is disclosed. The synthesis route is based on electrophilic aromatic substitutions of thionium ion species that are generated in-situ from aldehydes and thiols, affording benzyl sulfide that can be reduced with triethylsilane.
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Page/Page column 67
(2016/09/15)
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- ALKYLATION OF PHENOLIC COMPOUNDS
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The invention relates to a process for O-alkyiation of a phenolic compound comprising at least two hydroxyl groups bonded to an aromatic hydrocarbon, the process comprising reacting the phenolic compound with an alkylating agent in the presence of a base, at a suitable reaction temperature and for a suitable time period, thereby alkylating the at least two hydroxy] groups. The invention also relates to O-alkylaled phenolic compounds produced by this process.
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Page/Page column 38
(2015/04/28)
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- Si- and C-functional organosilicon building blocks for synthesis based on 4-Silacyclohexan-1-ones containing the silicon protecting groups MOP (4-Methoxyphenyl), DMOP (2,6-Dimethoxyphenyl), or TMOP (2,4,6-Trimethoxyphenyl)
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4-Silacyclohexan-1-ones 1a-1c, 4-silacyclohexan-1-one oximes 2a-2c, 1,4-azasilepan-7-ones 3a-3c, 1,4-azasilepanes 4a-4c, and 2-bromo-4-silacyclohexan-1-ones 5a and 5b were prepared in multistep syntheses, starting from trimethoxypropylsilane. All of these compounds represent C-functional (R2C=O, R2C=N-OH, R-NH(C=O)-R, R2NH, or R3C-Br) silicon-containing heterocycles that contain Si-MOP, Si-DMOP, or Si-TMOP moieties (MOP = 4-methoxyphenyl; DMOP = 2,6-dimethoxyphenyl; TMOP = 2,4,6-trimethoxyphenyl), which can be cleaved under mild conditions by protodesilylation. As a proof of principle, compounds 3a-3c were transformed quantitatively and selectively into the chlorosilane 6 (treatment with hydrogen chloride in dichloromethane). Thus, the C- and Si-functional compounds 1a-1c, 2a-2c, 3a-3c, 4a-4c, 5a, and 5b represent versatile building blocks for synthesis.
- Geyer, Marcel,Karlsson, Olle,Baus, Johannes A.,Wellner, Eric,Tacke, Reinhold
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p. 5804 - 5811
(2015/06/16)
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- Design, synthesis and biological activity of aromatic diketone derivatives as HIV-1 integrase inhibitors
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A series of aromatic diketone derivatives were designed and synthesized as potential HIV-1 integrase (IN) inhibitors and evaluated to determine their ability to inhibit the strand transfer process of HIV-1 integrase. The results indicate that (Z)-1-(3-acetyl-2-hydroxy-4,6-dimethoxyphenyl)-3-hydroxy-3-(substituted)phenylprop-2-en-1-one (5a-5d) can moderately inhibit HIV-1 integrase. The cyclization and condensation products (6a-6c and 7e-7f) of compounds 5a-5d show poor inhibitory activity against HIV-1 integrase. The molecular docking results indicate that the different types of compounds act on HIV-1 integrase in different ways, and these results can explain the differences in the inhibitory activities.
- Hu, Liming,Li, Zhipeng,Wang, Zhanyang,Liu, Gengxin,He, Xianzhuo,Wang, Xiaoli,Zeng, Chengchu
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p. 180 - 187
(2015/04/14)
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- Divergent and concise total syntheses of dihydrochalcones and 5-deoxyflavones recently isolated from Tacca species and Mimosa diplotricha
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Dihydrochalcones and 5-deoxyflavones are types of compounds possessing various biologically interesting properties. Herein, we report the concise and divergent total syntheses of several naturally occurring dihydrochalcones and 5-deoxyflavones from readily available starting materials. The divergent strategy is based around manipulation of a common chalcone scaffold and features application of Algar-Flynn-Oyamada oxidation and benzoquinone C-H activation methodologies. These are the first reported total syntheses of these biologically interesting compounds and the concise and flexible route should be readily amenable to future analogue generation. Furthermore, this work provides an illustration of the utility of divergent synthesis for the expedient and step-economical preparation of natural product libraries.
- Sum, Tze Han,Sum, Tze Jing,Stokes, Jamie E.,Galloway, Warren R.J.D.,Spring, David R.
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p. 4557 - 4564
(2015/06/08)
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- Aged red wine pigments as a source of inspiration for organic synthesis - The cases of the color-stable pyranoflavylium and flavylium-(4→8)-flavan chromophores
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Two flavylium-based chromophores peculiar to aged red wine pigments are investigated from a synthetic viewpoint. The condensation between easy-to-prepare 5-hydroxy-4-methylflavylium salts and aldehydes, giving birth to color-stable pyranoflavylium pigments, further proves efficient and wide in scope. A set of some twenty structurally-related flavylium-based pigments has been prepared and structure:color relationships are discussed. Furthermore, the synthesis of the flavylium-(4→8)-flavan chromophore is achieved via a novel three-step sequence. The elaborated sequence starts with an iodine-magnesium exchange from an 8-iodinated flavan, thus generating a magnesiated species that then smoothly reacts with a flavone to furnish an adduct, that finally leads to the expected chromophore via dehydration.
- Chassaing, Stefan,Isorez-Mahler, Géraldine,Kueny-Stotz, Marie,Brouillard, Raymond
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p. 3066 - 3078
(2015/05/04)
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- Base-catalysed cleavage of lignin β-O-4 model compounds in dimethyl carbonate
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A base-catalysed transformation and cleavage of lignin β-O-4 model compounds in dimethyl carbonate is reported. The reaction system consists of readily available bases and inexpensive dimethyl carbonate as a solvent and reagent, affording methoxy benzene or 2-aryloxyvinyl benzene derivatives in good to very good yields. The applicability of the system for the bond cleavage in an organosolv lignin sample was demonstrated.
- Dabral, Saumya,Mottweiler, Jakob,Rinesch, Torsten,Bolm, CarstenU
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supporting information
p. 4908 - 4912
(2015/11/11)
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- Reductive Alkylation of Arenes by a Thiol-Based Multicomponent Reaction
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A simple and highly chemo- and regioselective method for introducing primary alkyl substituents into aromatic compounds was developed. The method is based on an electrophilic aromatic substitution of an aldehyde, promoted by a thiol, to afford 1-(alkylthio)alkylarenes, which can either be reduced in situ with triethylsilane or reacted further. This multicomponent reaction enables the direct introduction of both aromatic and linear and branched aliphatic alkyl groups into arenes. The above one-pot protocol may be performed in air and in the presence of water and is compatible with various functional groups.
- Parnes, Regev,Pappo, Doron
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supporting information
p. 2924 - 2927
(2015/06/30)
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- A ligand-free, powerful, and practical method for methoxylation of unactivated aryl bromides by use of the CuCl/HCOOMe/MeONa/MeOH system
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A ligand-free, powerful, and practical method for mono and polymethoxylation of unactivated aryl bromides has been developed; CuCl was used as catalyst, HCOOMe as cocatalyst, and methanolic MeONa as both nucleophile and solvent. This eco-friendly procedure is characterized by operational simplicity, inexpensive substrates (unactivated mono to polybromoarenes), full conversion, and direct recovery of pure MeOH.
- Guo, Ying,Ji, Si-Zhe,Chen, Cheng,Liu, Hong-Wei,Zhao, Jian-Hong,Zheng, Yu-Lin,Ji, Ya-Fei
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p. 8651 - 8664
(2015/03/05)
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- Synthesis of 2-phenylnaphthalenes from styryl-2-methoxybenzenes
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A new simple and efficient method for the synthesis of 2-phenylnaphthalenes from electron-rich 1-styryl-2-methoxybenzenes has been described. The reaction proceeds via TFA catalyzed C-C bond cleavage followed by intermolecular [4+2]-Diels-Alder cycloaddition of an in situ formed styrenyl trifluoroacetate intermediate. The quantum chemical calculations identified the transition state for the cycloaddition reaction and helped in tracing the reaction mechanism. The method has been efficiently utilized for synthesis of the phenanthrene skeleton and a naphthalene-based potent and selective ER-β agonist. This journal is
- Mudududdla, Ramesh,Sharma, Rohit,Abbat, Sheenu,Bharatam, Prasad V.,Vishwakarma, Ram A.,Bharate, Sandip B.
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p. 12076 - 12079
(2015/02/19)
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- Synthesis of 4-silacyclohexan-1-ones and (4-silacyclohexan-1-yl)amines containing the silicon protecting groups MOP (4-methoxyphenyl), DMOP (2,4-dimethoxyphenyl), or TMOP (2,4,6-trimethoxyphenyl): Versatile Si- and C-functional building blocks for synthesis
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The 4-silacyclohexanones 1-6 were prepared in convenient multistep syntheses, starting from MeSi(OMe)3 and PhSi(OMe)3, respectively. Cleavage of the 4-methoxyphenyl (MOP), 2,6-dimethoxyphenyl (DMOP), and 2,4,6-trimethoxyphenyl (TMOP) protecting groups of 4-6 by treatment with HCl/Et2O in CH2Cl2 at 20 C gives the 4-chloro-4-silacyclohexanone 13. Reductive amination of 1-6 with NH3 or i-PrNH2 yields the respective (4-silacyclohexan-1-yl)amines 7-12. Compounds 1-12 and all new precursors synthesized were characterized by elemental analyses (C, H, N) or mass spectrometric investigations (ESI-HRMS) and by NMR spectroscopic studies (1H, 13C, 29Si). Compounds 1, 3, 5, and 6 and the precursors (MeO)2SiPh(TMOP) (21) and (CH2=CH)2SiPh(TMOP) (27) were additionally characterized by single-crystal X-ray diffraction. Compounds 1-12 with their Si- and C-functional groups represent versatile building blocks for synthesis.
- Fischer, Markus,Burschka, Christian,Tacke, Reinhold
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p. 1020 - 1029
(2014/03/21)
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- Palladium-catalyzed methoxylation of aromatic chlorides with borate salts
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Herein we disclose a simple palladiumcatalyzed transformation for the methoxylation of aromatic chlorides with tetramethoxyborate salts. The procedure provides a new and efficient synthetic tool for the introduction of a methoxy group into aromatic systems. In addition, the reaction can be achieved using a wide range of aromatic and heteroaromatic chlorides, the cheapest class of halides.
- Tolnai, Gergely L.,Petho, Bálint,Králl, Péter,Nováka, Zoltán
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supporting information
p. 125 - 129
(2014/03/21)
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- Synthesis of silicon-functionalized (silylmethyl)silanes and-dichlorocarbosilanes using the TMOP (2,4,6-trimethoxyphenyl) protecting group: (TMOP)Me2SiCH2Cl and (TMOP) 2MeSiCH2Cl as reagents to introduce the ClMe 2SiCH2, MeOMe2SiCH2, or Cl2MeSiCH2 group by nucleophilic substitution at silicon
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In this study, the synthetic potential of the 2,4,6-trimethoxyphenyl (TMOP)-substituted (chloromethyl)silanes (TMOP)Me2SiCH2Cl (1) and (TMOP)2MeSiCH2Cl (2) for the preparation of Si-functionalized (silylmethyl)silanes and α,ω-dichlorocarbosilanes (with skeletons consisting of alternate carbon and silicon atoms) was investigated. Compounds 1 and 2 were used as reagents to introduce the ClMe 2SiCH2, MeOMe2SiCH2, or Cl 2MeSiCH2 group by nucleophilic substitution at silicon. The three-step synthetic method involves the (i) transformation of 1 and 2 into (TMOP)Me2SiCH2MgCl, (TMOP)Me2SiCH 2Li, (TMOP)2MeSiCH2MgCl, and (TMOP) 2MeSiCH2Li, respectively, (ii) reaction of these nucleophiles with chloro- or methoxysilanes, and (iii) subsequent selective cleavage of the TMOP protecting group with HCl/Et2O or MeOH/[CF 3COOH]. Using this method, the following compounds were prepared: ClMe2SiCH2SiMe3 (3), ClMe2SiCH 2SiMe2Cl (4), ClMe2SiCH2SiMeCl 2 (5), ClMe2SiCH2SiCl3 (6), ClMe2SiCH2Si(OMe)3 (7), MeOMe 2SiCH2Si(OMe)3 (8), Cl2MeSiCH 2SiMe3 (9), Me2Si(CH2SiMe 2Cl)2 (10), and Me2Si(CH2SiMe 2CH2SiMe2Cl)2 (11).
- Laskowski, Nadine,Reis, Eva-Maria,Koetzner, Lisa,Baus, Johannes A.,Burschka, Christian,Tacke, Reinhold
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p. 3269 - 3278
(2013/07/27)
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- The first method for C-devinylation of aromatic systems
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This Letter describes the method for C-devinylation of aromatic systems for the first time. Vinylbenzenes on refluxing with trifluoroacetic acid produced corresponding devinylated products in excellent yields. Furthermore, 2,4,6-trimethoxy vinylbenzenes on treatment with hexamethylene tetraamine and trifluoroacetic acid exclusively produced 1,3-diformyl 2,4,6-trimethoxy benzene via tandem devinylation and diformylation reactions. A variety of aliphatic vinyl groups can be utilized but the reaction is limited to 1,3,5- trimethoxybenzene.
- Bharate, Sandip B.,Mudududdla, Ramesh,Sharma, Rohit,Vishwakarma, Ram A.
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supporting information
p. 2913 - 2915
(2013/06/27)
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- Mild aromatic palladium-catalyzed protodecarboxylation: Kinetic assessment of the decarboxylative palladation and the protodepalladation steps
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Mechanism studies of a mild palladium-catalyzed decarboxylation of aromatic carboxylic acids are described. In particular, reaction orders and activation parameters for the two stages of the transformation were determined. These studies guided development of a catalytic system capable of turnover. Further evidence reinforces that the second stage, protonation of the arylpalladium intermediate, is the rate-determining step of the reaction. The first step, decarboxylative palladation, is proposed to occur through an intramolecular electrophilic palladation pathway, which is supported by computational and mechanism studies. In contrast to the reverse reaction (C-H insertion), the data support an electrophilic aromatic substitution mechanism involving a stepwise intramolecular protonation sequence for the protodepalladation portion of the reaction.
- Dickstein, Joshua S.,Curto, John M.,Gutierrez, Osvaldo,Mulrooney, Carol A.,Kozlowski, Marisa C.
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p. 4744 - 4761
(2013/07/11)
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- The first total synthesis of tarennane, a potent antioxidant chalcone constituent from tarenna attenuate or Magnolia officinalis
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The convergent total synthesis of tarennane has been accomplished in six steps starting from commercially available phloroglucinol and guaiacol; the key step of the synthesis relies on a highly regioselective Heck reaction applying iodophenol and PdCl2(PPh3)2.
- Yang, Jincheng,Yang, Tao,Luo, Youfu,He, Jun,Shi, Jianyou,Peng, Aihua
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experimental part
p. 258 - 263
(2012/04/18)
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- Hammett analysis of a family of carbene-carbene complex equilibria
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p-X-substituted phenylchlorocarbenes (X = NO2, CF3, Cl, H, Me, and MeO) form π-type complexes with trimethoxybenzene in pentane. The carbenes and complexes are in equilibrium, and logarithms of the measured equilibrium constants are well correlated by Hammett σp constants with ρ = 2.48. The carbene complexes are characterized by UV-vis spectroscopy, and computational analysis is afforded by DFT calculations.(Figure Presented)
- Wang, Lei,Moss, Robert A.,Thompson, Jack,Krogh-Jespersen, Karsten
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supporting information; scheme or table
p. 1198 - 1201
(2011/04/27)
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- Pd(DPEPhos)Cl2-catalyzed Negishi cross-couplings for the formation of biaryl and diarylmethane phloroglucinol adducts
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Several functionalized biaryls and diarylmethanes containing the phloroglucinol subunit were synthesized in 55-85% yields using Negishi cross-couplings of 2,4,6-trimethoxyphenylzinc chloride with aryl and benzyl halides in the presence of catalytic quantities of Pd(DPEPhos)Cl2. These simple to prepare couplings were generally complete in 1-24 h depending on the halide, and were applicable to aryl and benzyl halides containing both electron-donating and electron-withdrawing groups.
- Dennis, Eric G.,Jeffery, David W.,Perkins, Michael V.,Smith, Paul A.
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experimental part
p. 2125 - 2131
(2011/04/22)
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- Total synthesis of 3′,3?-binaringenin and related biflavonoids
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The synthesis of natural 3++,3?-binaringenin and four related biflavonoids was performed in good overall yield (15-35%) starting from readily available phloroglucinol and 4-hydroxy- or 4-methoxybenzaldehyde. Preliminary results indicate that some of these compounds have an interesting activity against S. aureus. Georg Thieme Verlag Stuttgart.
- Sagrera, Gabriel,Seoane, Gustavo
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scheme or table
p. 2776 - 2786
(2010/10/19)
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- Synthesis and antitumor activity of diterpenylhydroquinone derivatives of natural ent-labdanes
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Two new compounds 2β-acetoxy-15-phenyl-(22,25-acetoxy)-ent-labda-8(17) , 13(E)-diene (9) and 2β-hydroxy-15-phenyl-(22,24,26-trimethoxy)-ent-labda- 8(17),13(E)-diene (10) have been prepared by an Electrophilic Aromatic Substitution (EAS) reaction between diterpenyl allylic alcohols and 1,4-hydroquinone or 1,3,5-trimethoxybenzene using BF3·Et 2O as a catalyst. These compounds, along with a series of natural ent-labdanes 3-8, have been evaluated for their in vitro cytotoxic activities against cultured human cancer cells of PC-3 and DU-145 human prostate cancer, MCF-7 and MDA-MB-231 breast carcinoma and dermal human fibroblasts (DHF). Some compounds displayed inhibition at μM IC50 values.
- Catalan, Luis Espinoza,Maturana, Evelyn Baeza,Marin, Karen Catalan,Olivares, Mauricio Osorio,Altamirano, Hector Carrasco,Fritis, Mauricio Cuellar,Garcia, Joan Villena
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scheme or table
p. 6502 - 6511
(2010/12/18)
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- Rh(I)-catalyzed decarboxylative transformations of arenecarboxylic acids: Ligand- and reagent-controlled selectivity toward hydrodecarboxylation or heck-mizoroki products
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(Chemical Equetion Presentation) A Rh(I)-based catalyst system has been developed to promote three types of decarboxylative transformations of arenecarboxylic acids: (1) hydrodecarboxylation, (2) Heck-Mizoroki olefination, and (3) conjugate addition. Scopes of reactions (1) and (2) were studied, and the ligand and reagent dependence of selectivity was explored.
- Sun, Zhong-Ming,Zhang, Jing,Zhao, Pinjing
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supporting information; experimental part
p. 992 - 995
(2010/06/16)
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- The iridium-catalyzed decarbonylation of aldehydes under mild conditions
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The catalytic decarbonylation of aldehydes has been developed using commercially available [IrCl(cod)]2 and PPh3 under mild conditions, and the method could be widely applicable to various substrates with different functionalities. The Royal Society of Chemistry.
- Iwai, Tomohiro,Fujihara, Tetsuaki,Tsuji, Yasushi
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experimental part
p. 6215 - 6217
(2009/05/06)
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- Miscrowave-assisted efficient synthesis of polymethoxyacetophenones and natural polymethoxyflavones, and thier inhibitory effects on melanogenesis
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Microwave, assisted Friedel-Crafts acetylation of polymethoxybenzenes with acetic anhydride in the presence of In(CF3SO3)3 under solvent-free conditions was achieved rapidly to give polymethoxyacetophenones in high yields. Microwave-assisted benzoylation of 2'-hydroxypolymethoxyacetophenones with polymethoxybenzoyl chlorides, followed by the rearrangement of the resulting benzoates and the final formation of natural polymethoxyflavones was achieved rapidly and efficiently. The polymethoxyflavones showed inhibitory effects on melanogenesis in human melanoma cells.
- Tsukayama, Masao,Kusunoki, Eiji,Hossain, Mohammad M.,Kawamura, Yasuhiko,Hayashi, Shinji
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p. 1589 - 1600
(2008/09/17)
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- Solvolysis of methoxy-substituted diaryliodonium tetrafluoroborates: Attempted generation of a stabilized aryl cation
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Solvolyses of monomethoxy- and dimethoxyphenyl(phenyl)iodonium (ArI +Ph) tetrafluoroborates were carried out in methanol and 2,2,2-trifluoroethanol (TFE) at 130°C. The solvolysis products include alkoxide substitution products (ArOR and PhOR) as well as iodoarenes (PhI and ArI). The ratios of ArOR/PhOR range from 8/2 to 4/6. The results are argued against formation of aryl cation. Copyright
- Fujita, Morifumi,Mishima, Eri,Okuyama, Tadashi
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p. 241 - 244
(2008/03/13)
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- A general and convenient method for the rhodium-catalyzed decarbonylation of aldehydes
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A practical protocol for the decarbonylation of a wide range of aldehydes has been developed by using commercially available RhCl3· SH2O and dppp in a diglyme solution. This method gives rise to decarbonylated products in good to high yield and is particularly useful because of its experimental simplicity, high generality and excellent level of functional group tolerance. The reaction has been applied in a tandem Oppenauer oxidation-decarbonylation sequence, which removes a hydroxymethyl group in one operation.
- Kreis, Michael,Palmelund, Anders,Bunch, Lennart,Madsen, Robert
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p. 2148 - 2154
(2007/10/03)
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- Sulfur-substituted α-alkyl phenethylamines as selective and reversible MAO-A inhibitors: Biological activities, CoMFA analysis, and active site modeling
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A series of phenethylamine derivatives with various ring substituents and with or without N-methyl and/or C-α methyl or ethyl groups was synthesized and assayed for their ability reversibly to inhibit monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). Several compounds showed potent and selective MAO-A inhibitory activity (IC50 in the submicromolar range) but none showed appreciable activity toward MAO-B. A three-dimensional quantitative structure-activity relationship study for MAO-A inhibition was performed on the series using comparative molecular field analysis (CoMFA). The resulting model gave a cross-validated q2 of 0.72 and showed that in this series of compounds steric properties of the substituents were more important than electrostatic effects. Molecular modeling based on the recently published crystal structure of inhibitor-bound MAO-A provided detailed evidence for specific interactions of the ligands with the enzyme, supported by previous references and consistent with results from the CoMFA. On the basis of these results, structural determinants for selectivity of substituted amphetamines for MAO-A are discussed.
- Gallardo-Godoy, Alejandra,Fierro, Angélica,McLean, Thomas H.,Castillo, Mariano,Cassels, Bruce K.,Reyes-Parada, Miguel,Nichols, David E.
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p. 2407 - 2419
(2007/10/03)
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