- A Cascade Strategy Enables a Total Synthesis of (±)-Morphine
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Morphine has been a target for synthetic chemists since Robinson proposed its correct structure in 1925, resulting in a large number of total syntheses of morphine alkaloids. Here we report a total synthesis of (±)-morphine that employs two key strategic cyclizations: 1) a diastereoselective light-mediated cyclization of an O-arylated butyrolactone to form a tricyclic cis-fused benzofuran and 2) a cascade ene–yne–ene ring closing metathesis to forge the tetracyclic morphine core. This approach enables a short and stereoselective synthesis of morphine in an overall yield of 6.6 %.
- Chu, Shuyu,Münster, Niels,Balan, Tudor,Smith, Martin D.
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- Structure–Activity Relationship of Anti-malarial Allylpyrocatechol Isolated from Piper betle
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Malaria disease remains a serious worldwide health problem. In South-East Asia, one of the malaria infection “hot-spots,” medicinal plants such as Piper betle have traditionally been used for the treatment of malaria, and allylpyrocatechol (1), a constituent of P. betle, has been shown to exhibit anti-malarial activities. In this study, we verified that 1 showed in vivo anti-malarial activity through not only intraperitoneal (i.p.) but also peroral (p.o.) administration. Additionally, some analogs of 1 were synthesized and the structure–activity relationship was analyzed to disclose the crucial sub-structures for the potent activity.
- Horii, Toshihiro,Itagaki, Sawako,Kawano, Tomikazu,Miyoshi, Akihito,Murakami, Nobutoshi,Tamura, Satoru
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p. 784 - 790
(2020/09/18)
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- Degradation of lignin with aqueous ammonium-based ionic liquid solutions under milder conditions
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This study investigates the performance of two aqueous ionic liquids (ILs), dimethylbutylammonium acetate ([DMBA][Ac]) and dimethylbutylammonium butanoate ([DMBA][B]), solutions for depolymerizing alkali lignin into valuable phenolic compounds. The favorable operation conditions, including reaction temperature and reaction time, are explored. The extent of depolymerization of the lignin is evaluated by analysis with gel permeation chromatography (GPC). The results show that the average molecular weights of the depolymerized lignin samples can be reduced by as high as 93.8% and 86.8% after treating with the aqueous [DMBA][Ac] and [DMBA][B], respectively. Moreover, the aromatic chemical species in the depolymerized solutions are identified by using gas chromatography?mass spectrophotometry (GC-MS). The confirmation of the chemical species is further made by using a series of spectroscopic techniques, such as FT-IR, and 1H NMR and 13C NMR spectroscopy. Promising results have been achieved for the depolymerization of the lignin into valuable chemicals by using the proposed green media, aqueous solutions of ionic liquids [DMBA][Ac] and [DMBA][B], under milder conditions.
- Gupta, Bhupender S.,Lee, Ming-Jer,Tolesa, Leta Deressa
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p. 3357 - 3365
(2019/02/25)
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- Structure–activity relationships and docking studies of hydroxychavicol and its analogs as xanthine oxidase inhibitors
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Hydroxychavicol (HC), which is obtained from the leaves of Piper betle LINN. (Piperaceae), inhibits xanthine oxidase (XO) with an IC50 value of 16.7μM, making it more potent than the clinically used allopurinol (IC50=30.7μM). Herein, a structure–activity relationship analysis of the polar part analogs of HC was conducted and an inhibitor was discovered with a potency 13 times that of HC. Kinetic studies have revealed that HC and its active analog inhibit XO in an uncompetitive manner. The binding structure prediction of these inhibitor molecules to the XO complex with xanthine suggested that both compounds (HC and its analog) could simultaneously form hydrogen bonds with xanthine and XO.
- Nishiwaki, Keiji,Ohigashi, Kanae,Deguchi, Takahiro,Murata, Kazuya,Nakamura, Shinya,Matsuda, Hideaki,Nakanishi, Isao
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p. 741 - 747
(2018/07/05)
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- A protocol to generate phthaloyl peroxide in flow for the hydroxylation of arenes
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A flow protocol for the generation of phthaloyl peroxide has been developed. This process directly yields phthaloyl peroxide in high purity (>95%) and can be used to bypass the need to isolate and recrystallize phthaloyl peroxide, improving upon earlier batch procedures. The flow protocol for the formation of phthaloyl peroxide can be combined with arene hydroxylation reactions and provides a method for the consumption of peroxide as it is generated to minimize the accumulation of large quantities of peroxide.
- Eliasen, Anders M.,Thedford, Randal P.,Claussen, Karin R.,Yuan, Changxia,Siegel, Dionicio
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supporting information
p. 3628 - 3631
(2014/08/05)
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- Palladium-catalyzed allylic arylation of allylic ethers with arylboronic acids using hydrazone ligands
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Unsymmetrical 1,3-diarylpropenes were synthesized in good to high yields by the palladium-catalyzed allylic arylation of allylic ethers, such as a cinnamyl phenyl ether, with a variety of arylboronic acids using a hydrazone 1a-Pd(OAc)2 system in DMAc/H2O. Using this catalyst, eugenol was also synthesized from allyl phenyl ether with (4-hydroxy-3- methoxyphenyl)boronic acid pinacol ester. A palladium-catalyzed allylic arylation of cinnamyl phenyl ether derivatives with a variety of arylboronic acids using 5 mol-% of a hydrazone 1a-Pd(OAc)2 system in DMAc/H 2O at 50 °C gave 1,3-diarylpropenes in good yields. We also succeeded with the synthesis of eugenol by a palladium-catalyzed allylic arylation. Copyright
- Mino, Takashi,Kogure, Taketo,Abe, Taichi,Koizumi, Tomoko,Fujita, Tsutomu,Sakamoto, Masami
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p. 1501 - 1505
(2013/05/09)
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- Expeditious synthesis of bioactive allylphenol constituents of the genus Piper through a metal-free photoallylation procedure
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Nine bioactive allylphenol (anisole) derivatives (e.g. eugenol, safrole and asaricin) present in several plants of the genus Piper have been synthesized in medium to high yield via aryl cation intermediates. This expeditious metal-free procedure involves the irradiation of the corresponding chlorophenols or chloroanisoles in a polar solvent (MeCN or, better, TFE or aqueous acetonitrile) in the presence of allyltrimethylsilane. Estragole has also been synthesized starting from the corresponding fluoroderivative and diazonium salt, though in a lower yield. The Royal Society of Chemistry 2005.
- Protti, Stefano,Fagnoni, Maurizio,Albini, Angelo
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p. 2868 - 2871
(2007/10/03)
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- STRUCTURE-ACTIVITY RELATIONSHIPS OF PHENYLPROPANOIDS AS GROWTH INHIBITORS OF THE GREEN ALGA SELENASTRUM CAPRICORNUTUM
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Twenty-seven commercial or synthetic phenylpropanoids have been tested in broth against the unicellular alga Selenastrum capricornutum.The antialgal activity seems to be linked to the number as well as to the position of the methoxyl group in the molecule.A slight effect of the side chain substitution was also observed. Key Word Index - Selenastrum capricornutum; allelochemicals; phenylpropanoids.
- Greca, Marina Della,Monaco, Pietro,Pollio, Antonino,Previtera, Lucio
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p. 4119 - 4124
(2007/10/02)
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