- Regioselective synthesis of gentisyl alcohol-type marine natural products
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Gentisyl alcohol-type natural products, possessing various important biological properties, have been synthesized from 4-methoxyphenol by using a selective phenol monohydroxymethylation/monochlorination, a CAN oxidation and a sodium dithionite reduction as the key steps. The natural product synthesis is efficient, atom- and step-economical, and requires no protecting groups.
- Wang, Hong-Shuang,Li, Hui-Jing,Wang, Long-Fei,Shen, Zhi-Lun,Wu, Yan-Chao
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supporting information
p. 1891 - 1896
(2018/05/29)
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- A supple red alkone epirubicin than star-intermediates of the synthesis method (by machine translation)
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The invention belongs to the field of medical synthesis, in particular relates to a supple red alkone epirubicin than star intermediate chemical synthesis method. The invention relates to 2, 5 - dihydroxy benzyl alcohol as the raw material synthetic suppl
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Paragraph 0034-0036
(2019/10/17)
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- Daunomycinone intermediate compound
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The invention belongs to the field of medicine synthesis and particularly provides a daunomycinone intermediate compound. Daunomycinone can be purely chemically synthesized by adoption of the intermediate compound. By adoption of 2,5-dyhydroxylbenzyl alco
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Paragraph 0128-0130
(2019/10/17)
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- Daunomycinone intermediate compound
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The invention belongs to the field of medicine synthesis and particularly provides a daunomycinone intermediate compound. Daunomycinone can be purely chemically synthesized by adoption of the intermediate compound. By adoption of 2,5-dyhydroxylbenzyl alco
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Paragraph 0039-0041
(2019/10/17)
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- Daunomycinone intermediate compound
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The invention belongs to the field of medicine synthesis and particularly provides a daunomycinone intermediate compound. By adoption of 2,5-dyhydroxylbenzyl alcohol as a raw material for daunomycinone synthesis, low cost of raw materials, mild reaction c
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Paragraph 0039-0040
(2019/10/17)
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- Daunomycinone intermediate compound
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The invention belongs to the field of medicine synthesis and particularly provides a daunomycinone intermediate compound. Daunomycinone can be purely chemically synthesized by adoption of the intermediate compound. By adoption of 2,5-dyhydroxylbenzyl alco
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Paragraph 0039-0041
(2019/10/17)
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- Daunomycinone intermediate compound
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The invention belongs to the field of medicine synthesis and particularly provides a daunomycinone intermediate compound. Daunomycinone can be purely chemically synthesized by adoption of the intermediate compound. By adoption of 2,5-dyhydroxylbenzyl alco
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Paragraph 0039-0040
(2019/10/17)
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- Daunomycinone intermediate compound
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The invention belongs to the field of medicine synthesis and particularly provides a daunomycinone intermediate compound. Daunomycinone can be purely chemically synthesized by adoption of the intermediate compound. By adoption of 2,5-dyhydroxylbenzyl alco
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Paragraph 0039-0041
(2019/10/17)
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- Lewis Base Catalyzed Intramolecular Reduction of Salicylaldehydes by Pinacol-Derived Chlorohydrosilane
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A newly developed stable chlorohydrosilane derived from pinacol is herein described. This was successfully used in the reduction of salicylaldehydes in reasonable to excellent yields (51–97 %). The ability of the hydrosilane to react as a reducing agent is increased upon the in situ formation of a trialkoxyhydrosilane and activation with a Lewis base, as further indicated by density functional theory studies. 1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU) was identified to be a suitable catalyst for this metal-free reduction, promoting the regio- and chemoselective reduction of aldehydes in ortho-position to phenols, despite the presence of vicinal ketones. The performance of pinacol-derived chlorohydrosilane in the reduction of salicylaldehydes was further observed to be superior to that of well-established commercially available chlorohydrosilanes.
- Assoah, Benedicta,Vale, Jo?o R.,Kalenius, Elina,Veiros, Luis F.,Candeias, Nuno R.
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supporting information
p. 2910 - 2917
(2018/06/27)
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- Synthesis of 2,5-(4-alkoxybenzoyloxy)benzyl acrylates and cinnamates, monomers for side chain liquid crystal polymers
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Abstract: A variety of 2,5-(4-alkoxybenzoyloxy)benzyl acrylates and cinnamates, which can serve as monomers for side chain liquid crystal polymers, were readily synthesized from hydroquinone. Instead of the rare and expensive 2,5-dihydroxybenzaldehyde, ch
- Li, Yong,Yuan, Yao,Yang, Yu-Guo,Li, Zhi
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- Preparation method of sateripol compounds
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The invention relates to a preparation method of sateripol compounds, and belongs to the field of chemical synthesis. 4-alkoxy saligenol compounds are prepared by carrying out a reaction of 4-alkoxy phenol compounds and aldehyde ketone compounds, the gent
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Paragraph 0010; 0013
(2017/03/18)
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- Substituent effects on oxidation-induced formation of quinone methides from arylboronic ester precursors
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A series of arylboronic esters containing different aromatic substituents and various benzylic leaving groups (Br or N+Me3Br -) have been synthesized. The substituent effects on their reactivity with H2O2 and formation of quinone methide (QM) have been investigated. NMR spectroscopy and ethyl vinyl ether (EVE) trapping experiments were used to determine the reaction mechanism and QM formation, respectively. QMs were not generated during oxidative cleavage of the boronic esters but by subsequent transformation of the phenol products under physiological conditions. The oxidative deboronation is facilitated by electron-withdrawing substituents, such as aromatic F, NO2, or benzylic N+Me 3Br-, whereas electron-donating substituents or a better leaving group favor QM generation. Compounds containing an aromatic CH 3 or OMe group, or a good leaving group (Br), efficiently generate QMs under physiological conditions. Finally, a quantitative relationship between the structure and activity has been established for the arylboronic esters by using a Hammett plot. The reactivity of the arylboronic acids/esters and the inhibition or facilitation of QM formation can now be predictably adjusted. This adjustment is important as some applications may benefit and others may be limited by QM generation. Tunable quinone methide formation: Aromatic substituents and the benzylic leaving group strongly affect the H 2O2-induced formation of quinone methides (QMs) from arylboronic esters (see scheme). The reactivity of arylboronic esters can be predictably adjusted by varying substituents. Copyright
- Cao, Sheng,Christiansen, Robin,Peng, Xiaohua
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p. 9050 - 9058
(2013/07/26)
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- Dual reactivity of hydroxy- and methoxy- substituted o-Quinone methides in aqueous solutions: Hydration versus tautomerization.
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4-Hydroxy-6-methylene-2,4-cyclohexadien-1-one (1) and 4-methoxy-6- methylene-2,4-cyclohexadien-1-one (2) were generated by efficient (Φ = 0.3) photodehydration of 2-(hydroxymethyl)benzene-1,4-diol (3a) and 2-(hydroxymethyl)-4-methoxyphenol (4a), respectively. o-Quinone methides 1 and 2 can be quantitatively trapped as Diels-Alder adducts with ethyl vinyl ether or intercepted by good nucleophiles, such as azide ion (kN3(1) = 3.15 × 104 M-1 s-1 and kN3(2) = 3.30 × 104 M-1 s-1). In aqueous solution, o-quinone methide 2 rapidly adds water to regenerate starting material (τH2O(2) = 7.8 ms at 25 °C). This reaction is catalyzed by specific acid (kH+(2) = 8.37 × 10 3 s-1 M-1) and specific base (k OH-(2) = 1.08 × 104 s-1 M -1) but shows no significant general acid/base catalysis. In sharp contrast, o-quinone methide 1 decays (τH2O(1) = 3.3 ms at 25 °C) via two competing pathways: nucleophilic hydration to form starting material 3a and tautomerization to produce methyl-p-benzoquinone. The disappearance of 1 shows not only specific acid (kH+(1) = 3.30 × 104 s-1 M-1) and specific base catalysis (kOH-(1) = 3.51 × 104 s -1 M-1) but pronounced catalysis by general acids and bases as well. The o-quinone methides 1 and 2 were also generated by the photolysis of 2-(ethoxymethyl)benzene-1,4-diol (3b) and 2-(ethoxymethyl)-4- methoxyphenol (4b), as well as from (2,5-dihydroxy-1-phenyl)methyl- (3c) and (2-hydroxy-5-methoxy-1-phenyl)methyltrimethylammonium iodides (4c). Short-lived (τ25°C ≈ 20 μs) precursors of o-quinone methides 1 and 2 were detected in the laser flash photolysis of 3a,b and 4a,b. On the basis of their reactivity, benzoxete structures have been assigned to these intermediates.
- Arumugam, Selvanathan,Popik, Vladimir V.
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scheme or table
p. 7338 - 7346
(2011/01/12)
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- Simple, mild, and efficient method for the reduction of 1,4-benzoquinones to hydroquinones by the action of NaN3
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A simple, mild, and efficient method is presented for the reduction of 1,4-benzoquinones to hydroquinones by the action of NaN3 under neutral conditions in the presence of water. Copyright Taylor & Francis Group, LLC.
- Algi, Fatih,Balci, Metin
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p. 2293 - 2297
(2007/10/03)
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