- A short synthesis of (±)-antroquinonol in an unusual scaffold of 4-hydroxy-2-cyclohexenone
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Antroquinonol, which was first isolated from a mushroom, Antrodia cinnamomea, found in Taiwan, is an anticancer compound with a unique core structure of 4-hydroxy-2,3-dimethoxycyclohex-2-enone carrying methyl, farnesyl and hydroxyl substituents in the 4,5-cis-5,6-trans configuration. A short synthesis of (±)-antroquinonol is accomplished in seven steps from 2,3,4-trimethoxyphenol, which is oxidized in methanol to a highly electron-rich substrate of 2,3,4,4-tetramethoxycyclohexadienone and then a Michael reaction with dimethylcuprate is performed as the key step, followed by alkylation, reduction and epimerization to incorporate the required substituents at three contiguous stereocenters.
- Hsu, Che-Sheng,Chou, Ho-Hsuan,Fang, Jim-Min
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Read Online
- Differing selectivities in mechanochemical versus conventional solution oxidation using Oxone
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A mechanochemical oxidation of methoxylated aromatic chemicals is described, providing an example of a very different selectivity as compared to solution-based chemistry. Oxone was shown to react with 1,2,3-trimethoxybenzene to yield predominantly 2,6-dimethoxybenzoquinone in the solid state or 2,3,4-trimethoxyphenol in solution. The difference in effective acidity of the reaction conditions was not apparently responsible for the observed selectivity. The mechanochemical method described is simple, reproducible, and gave higher yield at higher conversion of substrate compared to solution conditions.
- Collom,Anastas,Beach,Crabtree,Hazari,Sommer
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- Studies toward the development of antiproliferative neoclerodanes from salvinorin A
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The success rate for central nervous system (CNS) drug candidates in the clinic is relatively low compared to the industry average across other therapeutic areas. Penetration through the blood-brain barrier (BBB) to reach the therapeutic target is a major obstacle in development. The rapid CNS penetration of salvinorin A has suggested that the neoclerodane nucleus offers an excellent scaffold for developing antiproliferative compounds that enter the CNS. The Liebeskind-Srogl reaction was used as the main carbon-carbon bond-forming step toward the synthesis of quinone-containing salvinorin A analogues. Quinone-containing salvinorin A analogues were shown to have antiproliferative activity against the MCF7 breast cancer cell line, but show no significant activity at the κ-opioid receptors. In an in vitro model of BBB penetration, quinone-containing salvinorin A analogues were shown to passively diffuse across the cell monolayer. The analogues, however, are substrates of P-glycoprotein, and thus further modification of the molecules is needed to reduce the affinity for the efflux transporter.
- Vasiljevik, Tamara,Groer, Chad E.,Lehner, Kurt,Navarro, Hernan,Prisinzano, Thomas E.
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- An alternative route for the synthesis of 2,3,4,5-tetramethoxytoluene
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The transformation of the commercially available 2,3,4- trimetho×ybenzaldehyde to 2,3,4,5-tetrametho×ytoluene using a Dakin reaction to insert the extra oxygen, formylation, reduction and methylation of the phenolic hydro×yl group is described.
- Vera, William J.,Chinea, Kimberly,Banerjee, Ajoy K.
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- Total Synthesis of Dactylicapnosines A and B
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Dactylicapnosines A and B, two natural products from Dactylicapnos scandens, exhibited potent anti-inflammatory and analgesic activities both in vitro and in vivo. In this paper, we report our second-generation synthesis of dactylicapnosine A and the first total synthesis of dactylicapnosine B. Our synthetic route features acid-induced isomerization of o-quinone (16), Co-mediated regioselective ring contraction of p-quinone (8b), and oxidative methoxylation of enone (18). This modified sequence provides dactylicapnosine A in 14 steps with an overall yield of 12% from a known compound (14a) and also offers opportunities to synthesize dactylicapnosine-like analogues for biological investigations.
- Zhao, Yinjiao,Li, Yuda,Wang, Bei,Zhao, Jingfeng,Li, Liang,Luo, Xiao-Dong,Zhang, Hongbin
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Read Online
- Identification of Pyruvate Carboxylase as the Cellular Target of Natural Bibenzyls with Potent Anticancer Activity against Hepatocellular Carcinoma via Metabolic Reprogramming
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Cancer cell proliferation in some organs often depends on conversion of pyruvate to oxaloacetate via pyruvate carboxylase (PC) for replenishing the tricarboxylic acid cycle to support biomass production. In this study, PC was identified as the cellular target of erianin using the photoaffinity labeling-click chemistry-based probe strategy. Erianin potently inhibited the enzymatic activity of PC, which mediated the anticancer effect of erianin in human hepatocellular carcinoma (HCC). Erianin modulated cancer-related gene expression and induced changes in metabolic intermediates. Moreover, erianin promotes mitochondrial oxidative stress and inhibits glycolysis, leading to insufficient energy required for cell proliferation. Analysis of 14 natural analogs of erianin showed that some compounds exhibited potent inhibitory effects on PC. These results suggest that PC is a cellular target of erianin and reveal the unrecognized function of PC in HCC tumorigenesis; erianin along with its analogs warrants further development as a novel therapeutic strategy for the treatment of HCC.
- Chen, Yuwen,Huang, Yulan,Jiao, Wei,Li, Fu,Li, Suiyan,Li, Wenhua,Lin, Yuan,Liu, Wanli,Ma, Yuling,Sheng, Yuwen,Suksamrarn, Apichart,Wang, Fei,Wang, Jing,Wei, Xiao,Wisanwattana, Wisanee,Wu, Wenbi,Zeng, Zhongqiu,Zhang, Guolin,Zhang, Jichao,Zhu, Qiyu
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- Practical Synthesis of Polymethylated Flavones: Nobiletin and Its Desmethyl Derivatives
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We present a practical synthesis of the polymethoxylated citrus flavone nobiletin that is suitable for use on a hundred gram scale. Ready availability of this compound and its derivatives will aid detailed chemical-biological investigations of their biological activities, including activation of signaling via the cAMP-dependent protein kinase A/extracellular signal-related protein kinase/cAMP response element-binding protein pathway.
- Asakawa, Tomohiro,Sagara, Hiroto,Kanakogi, Masaki,Hiza, Aiki,Tsukaguchi, Yuta,Ogawa, Takahiro,Nakayama, Miho,Ouchi, Hitoshi,Inai, Makoto,Kan, Toshiyuki
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p. 595 - 602
(2019/04/01)
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- Rational design, synthesis and biological evaluation of ubiquinone derivatives as IDO1 inhibitors
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Indoleamine 2,3-dioxygenase 1 (IDO1) is an attractive therapeutic target for the treatment of cancer, chronic viral infections and neurological disorders characterized by pathological immune stimulation. Herein, a series of known metal-chelating ubiquinone derivatives were designed, synthesized and evaluated for the IDO1 inhibiting activities. The docking studies showed that the compounds 11, 16, 18 and coenzyme-Q1 exhibited different binding modes to IDO1 protein. Among these compounds, the most active compound is 16d with an IC50 of 0.13 μM in enzymatic assay. The results reveal that a possible halogen bonding interaction between the bromine atom (3-Br) and Cys129 significantly enhances the inhibition activity against IDO1. This study provides structural insights of the interactions between ubiquinone analogues and IDO1 protein for the further modification and optimization.
- Ding, Yuyang,Tang, Fei,Xue, Xiaoqian,Luo, Jinfeng,Hussain, Muzammal,Huang, Yanhui,Wang, Zhen,Jiang, Hao,Tu, Zhengchao,Zhang, Jiancun
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supporting information
(2019/05/21)
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- Polygala tenuifolia-Acori tatarinowii herbal pair as an inspiration for substituted cinnamic α-asaronol esters: Design, synthesis, anticonvulsant activity, and inhibition of lactate dehydrogenase study
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Inspired by the traditional Chinese herbal pair of Polygala tenuifolia-Acori Tatarinowii for treating epilepsy, 33 novel substituted cinnamic α-asaronol esters and analogues were designed by Combination of Traditional Chinese Medicine Molecular Chemistry (CTCMMC) strategy, synthesized and tested systematically not only for anticonvulsant activity in three mouse models but also for LDH inhibitory activity. Thereinto, 68–70 and 75 displayed excellent and broad spectra of anticonvulsant activities with modest ability in preventing neuropathic pain, as well as low neurotoxicity. The protective indices of these four compounds compared favorably with stiripentol, lacosamide, carbamazepine and valproic acid. 68–70 exhibited good LDH1 and LDH5 inhibitory activities with noncompetitive inhibition type, and were more potent than stiripentol. Notably, 70, as a representative agent, was also shown as a moderately positive allosteric modulator at human α1β2γ2 GABAA receptors (EC50 46.3 ± 7.3 μM). Thus, 68–70 were promising candidates for developing into anti-epileptic drugs, especially for treatment of refractory epilepsies such as Dravet syndrome.
- Bai, Yajun,He, Xirui,Bai, Yujun,Sun, Ying,Zhao, Zefeng,Chen, Xufei,Li, Bin,Xie, Jing,Li, Yang,Jia, Pu,Meng, Xue,Zhao, Ye,Ding, Yanrui,Xiao, Chaoni,Wang, Shixiang,Yu, Jie,Liao, Sha,Zhang, Yajun,Zhu, Zhiling,Zhang, Qiang,Zhao, Yuhui,Qin, Fanggang,Zhang, Yi,Wei, Xiaoyang,Zeng, Min,Liang, Jing,Cuan, Ye,Shan, Guangzhi,Fan, Tai-Ping,Wu, Biao,Zheng, Xiaohui
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- Synthesis of isoflavones by tandem demethylation and ring-opening/cyclization of methoxybenzoylbenzofurans
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The unexpected conversion of benzoylbenzofurans into isoflavones through an intramolecular cascade that involves deprotection and ring-opening/cyclization is described. This was discovered in an investigation of the possible transformation of benzoylbenzofurans into coumaronochromones. This route affords isoflavones in two major steps from acetophenones and benzoquinones. The transformation was validated by synthesizing differently substituted isoflavone derivatives and further applied to a concise synthesis of a potential anticancer lead compound, glaziovianin A (1).
- Kunyane, Phaladi,Sonopo, Molahlehi S.,Selepe, Mamoalosi A.
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supporting information
p. 3074 - 3082
(2019/11/19)
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- Antimicrobial agent isolated from Coptidis rhizome extract incubated with Rhodococcus sp. strain BD7100
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Coptidis rhizome (CR) is a widely used herbal medicine that contains protoberberine-type alkaloids. CR extract exhibits various pharmacologic activities. A previous study reported the isolation of Rhodococcus sp. strain BD7100 as a berberine (BBR)-utilizing bacterium, and the BBR-degradation pathway has been investigated. When we incubated strain BD7100 cells with CR extract, the number of viable cells declined with the degradation of components in the CR extract, and the culture broth exhibited antibacterial activity against strain BD7100. These results suggest that CR extract cultured in the presence of strain BD7100 contains one or more antibacterial agents. In this study, we isolated coptirhoquinone A (1) from CR extract incubated with strain BD7100 in Luria–Bertani (LB) medium, and the structure was elucidated using NMR and MS analysis. We also report the total synthesis and antimicrobial activities of 1 against bacteria, fungi, and Pythium sp.
- Ishikawa, Kazuki,Takahashi, Kazunori,Hosoi, Syun,Takeda, Hisashi,Yoshida, Hinaka,Wakana, Daigo,Tsubuki, Masayoshi,Sato, Fumihiko,Tojo, Motoaki,Hosoe, Tomoo
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- NOVEL SMALL MOLECULE DRUG CONJUGATES OF GEMCITABINE DERIVATIVES
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Disclosed are compounds having formula (I) or a pharmaceutically acceptable salt, ester, amide, solvate, or stereoisomer thereof, wherein L, Y1, Y2, Y3, Y4, Y5, Z1, Z2, Z3, Z4, Z5, Z6, and Effector are each as defined in the specification; compositions thereof; uses thereof; and methods of use thereof.
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Page/Page column 69; 70
(2019/08/26)
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- SMALL MOLECULE DRUG CONJUGATES OF GEMCITABINE MONOPHOSPHATE
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Disclosed are compounds having formula (I): or a pharmaceutically acceptable salt, ester, amide, solvate, or stereoisomer thereof, wherein L, Y1, Y2, Y3, Y4, Y5, Z1, Z2, Z3, Z4, Z5, Z6 are each as defined in the specification; compositions thereof; uses thereof; and methods of use thereof.
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(2019/08/26)
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- Bioinspired Total Synthesis of Bussealin e
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The first total synthesis of bussealin E, a natural product with a unique cycloheptadibenzofuran scaffold, is reported. A strategy inspired by a proposed biosynthesis was employed whereby a diphenylpropane derivative underwent an oxidative phenolic coupling to forge the tetracyclic ring system. The synthesis of the diphenylpropane featured a key sp2-sp3 Hiyama coupling between a vinyldisiloxane and a benzylic bromide.
- Twigg, David G.,Baldassarre, Leonardo,Frye, Elizabeth C.,Galloway, Warren R. J. D.,Spring, David R.
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supporting information
p. 1597 - 1599
(2018/03/23)
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- Efficient cross-coupling of aryl/alkenyl triflates with acyclic secondary alkylboronic acids
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Aryl-secondary alkyl cross-coupling with aryl sulfonate esters as coupling partners remains a significant challenge. Efficient cross-coupling between aryl/alkenyl triflates and acyclic secondary alkylboronic acids is realized for the first time to provide a series of sterically congested acyclic secondary alkyl arenes/olefins in good to excellent yields. The employment of sterically bulky P,PO ligand L1/L2 is crucial for the high yields and selectivities. The method has enabled a concise and 4-step synthesis of a key intermediate of male contraceptive agent and PAF antagonist gossypol.
- Si, Tengda,Li, Bowen,Xiong, Wenrui,Xu, Bin,Tang, Wenjun
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supporting information
p. 9903 - 9909
(2017/12/12)
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- COMPOSITIONS AND METHODS FOR THE PREPARATION OF 4-OXY-2-CYCLOHEXENONE AND 6-OXY-2-CYCLOHEXENONE COMPOUNDS
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The present invention relates to a new synthetic route to 4-oxy-2-cyclohexenone and 6-oxy-2- cyclohexenone compounds useful for treatment of cancers and/or diseases, and the intermediates thereto. Examples of these cyclohexenone compounds include, but not limited to, A. cinnamomea active medicinal substances such as antroquinonol, antroquinonol B, antroquinonol C, and antroquinonol D. The intermediates include the compounds of formulae (I), (II) and (III), and the cyclohexenone compounds have the structures of formulae (IV), (V), (VI) and (VII).
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Paragraph 00228
(2016/02/05)
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- Selective Claisen rearrangement and iodination for the synthesis of polyoxygenated allyl phenol derivatives
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Allyl aryl ethers and allyl phenol derivatives were prepared starting from commercial or synthetized phenols. Either Williamson reaction or Et2AlCl catalyzed Claisen rearrangement was performed to obtain the polyoxygenated molecules. The pivotal allyl phenols were then modified by methylation, iodocyclization or electrophilic aromatic iodination to afford the polyoxygenated derivatives in good to excellent yields. Additionally, their antibacterial properties were also investigated against Gram-positive and Gram-negative bacteria.
- Bochicchio, Antonella,Cefola, Rossella,Choppin, Sabine,Colobert, Fran?oise,Di Noia, Maria Antonietta,Funicello, Maria,Hanquet, Gilles,Pisano, Isabella,Todisco, Simona,Chiummiento, Lucia
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supporting information
p. 4053 - 4055
(2016/08/18)
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- Divergent Total Syntheses of Flavonoid Natural Products Isolated from Rosa rugosa and Citrus unshiu
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The concise and step-economical total syntheses of three hydroxyaurones and one polymethoxyflavone from readily available starting materials is described. A divergent synthetic strategy is employed, which centres on a common chalcone scaffold from which both the aurone and flavone frameworks can be accessed through the use of different oxidative cyclisation methods. These are the first reported total syntheses of these biologically interesting compounds.
- Sum, Tze Jing,Sum, Tze Han,Galloway, Warren R. J. D.,Spring, David R.
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supporting information
p. 1725 - 1727
(2016/07/06)
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- TUBULIN BINDING AGENTS
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The invention provides combretastatin A-4 like compounds that are modified to have enhanced tubulin binding activity and in some embodiments the ability to promote accumulation in the vasculature undergoing angiogenesis (homing activity). The compounds are based on the combretastatin A-4 skeletal structure having a tubulin-binding pharmacophore comprising two fused rings (A and B rings) in which the B ring is substituted with (a) an aromatic ring structure (C ring) and (b) a second substituent/functional group that comes off the B ring. The aromatic ring structure is typically a six membered ring phenolic or aniline structure, or may also be a fused ring structure such as a substituted or unsubstituted naphthalene. The second substituent on the B ring may for example be a substituent which has been found to provide enhanced tubulin binding activity (for example a carbonyl group), or may be a substituent that facilitates functionalisation of the B ring (for example an hydroxyl or amine group), or it may be a binding agent for a target that is preferentially expressed on vasculature undergoing angiogenesis, and not expressed on quiescent vasculature.
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Paragraph 0413; 0414; 0415
(2015/02/18)
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- Efficient synthesis of sterically hindered arenes bearing acyclic secondary alkyl groups by suzuki-miyaura cross-couplings
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Bulky P,P-O ligands were designed to inhibit isomerization and reduction side reactions during the cross coupling between sterically hindered aryl halides and alkylboronic acids. Suzuki-Miyaura cross-couplings between di-ortho-substituted aryl bromides and acyclic secondary alkylboronic acids have been achieved with high yields. The method has also enabled the preparation of ortho-alkoxy di-ortho-substituted arenes bearing isopropyl groups in excellent yields. The utility of the synthetic method has been demonstrated in a late-stage modification of estrone and in the application to a new synthetic route toward gossypol. No side reaction: The shown bulky P,P-O ligands (right) successfully inhibit isomerization and reduction side reactions of the cross-coupling of sterically hindered substrates such as di-ortho-substituted aryl bromides with acyclic secondary alkylboronic acids. The method also allows the preparation of ortho-alkoxy di-ortho-substituted isopropyl arenes in excellent yields.
- Li, Chengxi,Chen, Tianyu,Li, Bowen,Xiao, Guolan,Tang, Wenjun
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supporting information
p. 3792 - 3796
(2015/03/18)
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- Antimitotic and antivascular activity of heteroaroyl-2-hydroxy-3,4,5-trimethoxybenzenes
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This study reports the synthesis of a series of heteroaroyl-2-hydroxy-3,4,5-trimethoxybenzenes, which are potent antitubulin agents. Compound 13, (2-hydroxy-3,4,5-trimethoxyphenyl)-(6-methoxy-1H-indol-3-yl)-methanone exhibits marked antiproliferative activity against KB and MKN45 cells with IC50 values of 8.8 and 10.5 nM, respectively, binds strongly to the colchicine binding site and leads to inhibition of tubulin polymerization. It also behaves as a vascular disrupting agent which suppresses the formation of capillaries. The C2-OH group in the A-ring of this compound not only retains the biological activity but has valuable physicochemical properties.
- Lee, Hsueh-Yun,Chang, Chih-Yi,Lai, Mei-Jung,Chuang, Hsun-Yueh,Kuo, Ching-Chuan,Chang, Chi-Yen,Chang, Jang-Yang,Liou, Jing-Ping
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p. 4230 - 4236
(2015/08/03)
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- Antimitotic and vascular disrupting agents: 2-Hydroxy-3,4,5- trimethoxybenzophenones
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2-Hydroxy-3,4,5-trimethoxybenzophenones (8-16) manifest pseudo-ring formation involving intramolecular hydrogen bonding of the 2-OH and the carbonyl group. Among the synthetic products described in this report, (3-hydroxy-4-methoxyphenyl)(2-hydroxy-3,4,5-trimethoxyphenyl)-methanone (14) and (3-amino-4-methoxyphenyl)(2-hydroxy-3,4,5-trimethoxy-phenyl)methanone (16) exhibit significant antiproliferative activity against KB cells with IC 50 values of 11.1 and 11.3 nM, respectively. These two compounds also displayed tubulin affinity comparable to that of combretastatin A-4. In studies with human umbilical vein endothelial cells, compounds 14 and 16 revealed concentration-dependent vascular-disrupting properties. The results support the rationale of the pseudo-ring concept and suggest further investigation of A-ring modification in these benzophenones.
- Chang, Chih-Yi,Chuang, Hsun-Yueh,Lee, Hsueh-Yun,Yeh, Teng-Kuang,Kuo, Ching-Chuan,Chang, Chi-Yen,Chang, Jang-Yang,Liou, Jing-Ping
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p. 306 - 314
(2014/04/03)
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- Synthesis, in vitro cytotoxicity and apoptosis inducing study of 2-aryl-3-nitro-2 H -chromene derivatives as potent anti-breast cancer agents
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A series of 2-aryl-3-nitro-2H-chromenes 4a-u were designed as hybrid analogs of flavanone, β-nitrostyrene and nitrovinylstilbene scaffolds. They were synthesized from the reaction of appropriate β-nitrostyrenes and salicylaldehydes in good yields. In vitro cytotoxic activities of compounds 4a-u were tested against breast cancer cell lines including MCF-7, T-47D and MDA-MB-231. Most compounds exhibited good cytotoxic activity against selected cell lines, being more potent than standard drug etoposide. Representatively, 8-methoxy-3-nitro-2-(4-chlorophenyl)-2H-chromene (4l) with IC50 Combining double low line 0.2 μ4M against MCF-7 cells, was 36-times more potent than etoposide. Apoptosis as a mechanism of cell death for selected compounds 4h and 4l was confirmed morphologically by acridine orange/ethidium bromide double staining and TUNEL analysis, as well as caspase-3 activation assay.
- Rahmani-Nezhad, Samira,Safavi, Maliheh,Pordeli, Mahboobeh,Ardestani, Sussan Kabudanian,Khosravani, Leila,Pourshojaei, Yaghoub,Mahdavi, Mohammad,Emami, Saeed,Foroumadi, Alireza,Shafiee, Abbas
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p. 562 - 569
(2015/01/09)
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- PET imaging of nobiletin based on a practical total synthesis
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A practical synthesis of nobiletin, a polymethoxylated citrus flavone, was accomplished by utilizing our novel flavone synthesis. Synthetic nobiletin was labelled by selective demethylation and rapid incorporation of 11C atom. Positron emission tomography images successfully visualized the brain distribution, which may provide therapeutic benefits in the treatment of Alzheimer's disease. The Royal Society of Chemistry.
- Asakawa, Tomohiro,Hiza, Aiki,Nakayama, Miho,Inai, Makoto,Oyama, Dai,Koide, Hiroyuki,Shimizu, Kosuke,Wakimoto, Toshiyuki,Harada, Norihiro,Tsukada, Hideo,Oku, Naoto,Kan, Toshiyuki
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p. 2868 - 2870
(2011/04/22)
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- Design and synthesis of novel quinone inhibitors targeted to the redox function of apurinic/apyrimidinic endonuclease 1/redox enhancing factor-1 (Ape1/Ref-1)
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The multifunctional enzyme apurinic endonuclease 1/redox enhancing factor 1 (Ape1/ref-1) maintains genetic fidelity through the repair of apurinic sites and regulates transcription through redox-dependent activation of transcription factors. Ape1 can therefore serve as a therapeutic target in either a DNA repair or transcriptional context. Inhibitors of the redox function can be used as either therapeutics or novel tools for separating the two functions for in vitro study. Presently there exist only a few compounds that have been reported to inhibit Ape1 redox activity; here we describe a series of quinones that exhibit micromolar inhibition of the redox function of Ape1. Benzoquinone and naphthoquinone analogues of the Ape1-inhibitor E3330 were designed and synthesized to explore structural effects on redox function and inhibition of cell growth. Most of the naphthoquinones were low micromolar inhibitors of Ape1 redox activity, and the most potent analogues inhibited tumor cell growth with IC50 values in the 10-20 μM range.
- Nyland II, Rodney L.,Luo, Meihua,Kelley, Mark R.,Borch, Richard F.
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scheme or table
p. 1200 - 1210
(2010/07/18)
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- PRODRUGS OF OXAZOLIDINONE CETP INHIBITORS
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The compounds of Formula I are prodrugs of CETP inhibitors having a central oxazolidinone ring. The compounds cyclize by the elimination of HX to form an oxazolidinone ring after administration to a patient.
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(2010/04/27)
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- Total synthesis of polemannones B and C
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The first total synthesis of polemannones B and C, higly oxygenated benzoxanthenones derivatives from Polemannia montana, is reported employing our new catalytic Cu(II)/sparteine system for β,β-phenolic couplings and tandem inverse-electron demand Diels-Alder reaction cascade in 75-90% yield.
- Fadeyi, Olugbeminiyi O.,Nathan Daniels,DeGuire, Sean M.,Lindsley, Craig W.
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body text
p. 3084 - 3087
(2009/10/04)
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- Nucleophilic substitution of nitro groups by [18F]fluoride in methoxy-substituted ortho-nitrobenzaldehydes-A systematic study
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As model reactions for the introduction of [18F]fluorine into aromatic amino acids, the replacement of NO2 by [18F]fluoride ion in mono- to tetra-methoxy-substituted ortho-nitrobenzaldehydes was systematically investigated. Unexpectedly, the highly methoxylated precursors 2,3,4-trimethoxy-6-nitrobenzaldehyde and 2,3,4,5-tetramethoxy-6-nitrobenzaldehyde showed high maximum radiochemical yields (82% and 48% respectively). When the electrophilicity of the leaving group substituted carbon atom is expressed by its 13C NMR chemical shift a good correlation with the reaction rate at the beginning of the reaction (first min) was found (R2 = 0.89), whereas the maximum radiochemical yields correlated much poorer with this electrophilicity parameter. This may be caused by side reactions becoming influencial in the further reaction course. As possible side reactions the demethylation of methoxy groups and intramolecular redox reactions could be detected by HPLC/MS.
- Shen, Bin,L?ffler, Dirk,Reischl, Gerald,Machulla, Hans-Jürgen,Zeller, Klaus-Peter
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experimental part
p. 216 - 224
(2009/07/25)
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- Quinol fatty alcohols as promoters of axonal growth
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The synthesis of three series of quinol fatty alcohols (QFAs) and their biological activities on the promotion of axonal growth are described. Interestingly, the 15-(2,5-dimethoxyphenyl)pentadecan-1-ol, the QFA bearing 15 carbon atoms on the side chain (n = 15), shows the most potent promotion of axonal growth in the presence of both permissive and non-permissive naturally occurring substrates such as Sema3A and myelin proteins.
- Hanbali, Mazen,Vela-Ruiz, Marta,Bagnard, Dominique,Luu, Bang
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p. 2637 - 2640
(2007/10/03)
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- An efficient synthesis of benzofurans and their application in the preparation of natural products of the genus Calea
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The intramolecular cyclization of the β-substituted olefins methyl 2-aryloxy-3-dimethylaminopropenoates 3a-3f catalyzed by Lewis acids leads to a short and novel synthesis of benzofurans 2a-2f. When the olefins 4-dimethylamino-3-aryloxy-3-buten-2-ones 4a-4f were used, the cyclization process was faster and provided the corresponding substituted 2-acetylbenzofurans 1a-1f. Among the latter, naturally occurring compounds calebertin (1a), caleprunin A (1b), and caleprunin B (1c) were prepared in good overall yields. These benzofurans were also obtained by direct treatment under MW irradiation of the precursors 1-aryloxypropan-2-ones 7a-7c with DMFDMA, followed by addition of the catalyst, resulting in a route that was one step shorter.
- Del Carmen Cruz, María,Tamariz, Joaquín
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p. 10061 - 10072
(2007/10/03)
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- A new fluorogenic transformation: Development of an optical probe for coenzyme Q
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(Chemical Equation Presented) A new fluorogenic transformation based on a quinone reduction/lactonization sequence has been developed and evaluated as a tool for probing redox phenomena in a biochemical context. The probe presented herein is an irreversible redox probe and is reduced selectively by biologically relevant quinols such as ubiquinol but is inert to reduced nicotinamides (e.g., NADH). The ensuing cyclization is fast and quantitative and provides a measurable optical response.
- Tremblay, Matthew S.,Sames, Dalibor
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p. 2417 - 2420
(2007/10/03)
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- Desmethylubiquinone Q2 from the Far-Eastern ascidian Aplidium glabrum: Structure and synthesis
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Two new diprenylquinones, glabruquinone A (desmethylubiquinone Q 2) having cancer preventive properties and its minor isomer Glabruquinone B were isolated from the ascidian Aplidium glabrum. Their structures have been elucidated by NMR and mass spectra and confirmed by synthesis.
- Shubina, Larisa K.,Fedorov, Sergey N.,Radchenko, Oleg S.,Balaneva, Nadezhda N.,Kolesnikova, Sophia A.,Dmitrenok, Pavel S.,Bode, Ann,Dong, Zigang,Stonik, Valentin A.
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p. 559 - 562
(2007/10/03)
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- The total synthesis of an aurone isolated from Uvaria hamiltonii: Aurones and flavones as anticancer agents
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The naturally occurring aurone 1, isolated from Uvaria hamiltonii, and a series of aurones analogues based structurally on known tubulin binding agents were prepared and evaluated for anticancer activity. Aurone 20 was the most active (IC50 K562 50 nM) and caused significant G2/M cell-cycle arrest.
- Lawrence, Nicholas J.,Rennison, David,McGown, Alan T.,Hadfield, John A.
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p. 3759 - 3763
(2007/10/03)
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- Method for the production of alkoxy- and aryloxy-phenols
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Alkoxybenzaldehydes and aryloxybenzaldehydes are converted to the corresponding phenols by reacting the benzaldehydes in an organic solvent phase with formic acid and hydrogen peroxide in an aqueous solvent phase to produce the corresponding formate ester. The formate ester is then saponified to produce the corresponding phenol.
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- Oxidation of Benzaldehydes Catalyzed by Methyltrioxorhenium with Hydrogen Peroxide
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Methyltrioxorhenium-catalyzed oxidation of benzaldehydes with hydrogen peroxide gives corresponding phenols in good yield.Benzaldehydes substituted with methoxy or hydroxyl groups at 2- and/or 4-position are good substrates for this reaction.
- Yamazaki, Shigekazu
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p. 127 - 128
(2007/10/02)
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- Preparation of methoxyphenols by oxidation of methoxybenzaldehydes with hydrogen peroxide in presence of p-toluenesulphonic acid
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Methoxyphenols have been prepared efficiently from the corresponding methoxybenzaldehydes by oxidation with hydrogen peroxide at room temperature in the presence of p-toluenesulphonic acid in methanol.
- Baruah, Robindra N.
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p. 1103 - 1104
(2007/10/02)
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- The Baeyer-Villiger Oxidation of Aromatic Aldehydes and Ketones with Hydrogen Peroxide Catalyzed by Selenium Compounds
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A series of organoselenium compounds was investigated as activators of hydrogen peroxide in the Baeyer-Villiger oxidation.As a result, a convenient and cheap method for transformation of aromatic aldehydes, having polycondensed ring systems or electron-donating substituents, and polymethoxy derivatives of acetophenone, into phenols was elaborated.This method utilizes hydrogen peroxide activated by areneseleninic acids, as oxidizing agent.
- Syper, Ludwik
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p. 167 - 172
(2007/10/02)
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- The Structure and Synthesis of Nepenthone-A, a Naphthoquinone from Nepenthes rafflesiana
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The structure of a naphthoquinone, nepenthone-A, isolated from Nepenthes rafflesiana Jack, is shown to be 4,7-dihydroxy-9-methoxy-6-methylnaphto-1,3-dioxole-5,9-dione (6), firs by the synthesis of its di-O-methyl derivative (7), and then by synthesis of the natural product.
- Rizzacasa, Mark A.,Sargent, Melvyn V.
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p. 2017 - 2022
(2007/10/02)
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- Syntheses of Agehoustins-A and B
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Agehoustins-A and B formulated as 5,6,7,8,2',3',4',5'-octamethoxyflavone (I) and 5,6,7,2',3',4',5'-heptamethoxyflavone (II) respectively, have been synthesised by the cyclodehydrogenations of the corresponding 2'-hydroxy-3',4',5',6',2,3,4,5-octamethoxychalkone (III) and 2'-hydroxy-4',5',6',2,3,4,5-heptamethoxychalkone (IV).
- Bhardwaj, D. K.,Chand, Gyan,Jain, Anita,Srivastava, Nagesh,Sharma, A. K.
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p. 1163 - 1164
(2007/10/02)
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- Acid-Catalyzed Oxidation of Benzaldehydes to Phenols by Hydrogen Peroxide
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A wide variety of benzaldehydes were oxidized to phenols by hydrogen peroxide in acidic methanol.
- Matsumoto, Masakatsu,Kobayashi, Hisako,Hotta, Yasushi
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p. 4740 - 4741
(2007/10/02)
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- SYNTHESIS OF WEBERINE AND NORWEBERINE AND THEIR 1-METHYL CONGENERS
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The synthesis of 2-methyl-5,6,7,8-tetramethoxy-1,2,3,4-tetrahydroisoquinoline (weberine) 5 from 2,3,4,5-tetramethoxy-β-phenylethylamine via norweberine 4 is described.The synthesis of their 1-methyl homologs was also accomplished.
- Takahashi, Kimio,Brossi, Arnold,Diseases, Kidney
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p. 691 - 695
(2007/10/02)
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- SYNTHESIS OF UBIQUINONE AND MENAQUINONE ANALOGUES BY OXIDATIVE DEMETHYLATION OF ALKENYLHYDROQUINONE ETHERS WITH ARGENTIC OXIDE OR CERIC AMMONIUM NITRATE IN THE PRESENCE OF 2,4,6-PYRIDINE-TRICARBOXYLIC ACID
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It was found that alkenylhydroquinone ethers demethylated with argentic oxide or ceric ammonium nitrate in the presence of 2,4,6-pyridinetricarboxylic acid as a catalyst and afforded ubiquinone-2, menaquinone-2 and their analogs in yields of 53 to 89 percent.The new approach to the synthesis of starting alkenylhydroquinone ethers as well as 2,4,6-pyridinetricarboxylic acid and its derivatives has been reported.
- Syper, L.,Kloc, K.,Mlochowski, J.
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p. 123 - 129
(2007/10/02)
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- A Novel Synthesis of 2,3-Dimethoxy-5-methyl-p-benzoquinone
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2,3-Dimethoxy-5-methyl-p-benzoquinone (3), an important intermediate in the synthesis of ubiquinones (1), was synthesized from 3,4,5-trimethoxysalicylic acid (6) or 2,3,4-trimethoxybenzaldehyde (9). 6 was reduced via the ethoxycarbonyl derivative (7) to 6-methyl-2,3,4-trimethoxyphenol (8) with sodium borohydride, and then 8 was oxidized to 3 in high yield with ferric chloride.On the other hand, 2,3,4-trimethoxyphenol (10) was obtained from 9 by the Baeyer-Villiger reaction or treatment with hydrogen peroxide under acidic or basic conditions, and then converted into 8 by reductive methylation.Sodium borohydride reduction of the Mannich base (11) of 10 also gave 8.Keywords - 2,3-dimethoxy-5-methyl-p-benzoquinone; ubiquinones; 3,4,5-trimethoxysalicylic acid; 2,3,4-trimethoxybenzaldehyde; 6-methyl-2,3,4-trimethoxyphenol; 2,3,4-trimethoxyphenol; 6-(N,N-dimethylamino)methyl-2,3,4-trimethoxyphenol; sodium borohydride reduction; reductive methylation
- Minami, Norio,Kijima, Shizumasa
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p. 1648 - 1650
(2007/10/02)
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