- Total Synthesis of the Ambigols: A Cyanobacterial Class of Polyhalogenated Natural Products
-
The first total synthesis of all members of the cyanobacterial natural product class of the ambigols is described. Key steps of the synthetic strategy are the formation of sterically demanding mono- and bis-iodonium salts to install the required biaryl ether structural elements and Suzuki cross-coupling giving straightforward access to the biaryl bonds. The synthetic methods are also utilized to construct unnatural or hypothetical ambigols that are still awaiting discovery from Nature.
- Milzarek, Tobias M.,Gulder, Tobias A. M.
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supporting information
p. 102 - 106
(2021/01/09)
-
- Synthesis of a TNF inhibitor, flurbiprofen and an: I -Pr analogue in enantioenriched forms by copper-catalyzed propargylic substitution with Grignard reagents
-
The copper-catalyzed substitution reaction of diethyl phosphate derived from TMSCCCH(OH)CH2CH2OTBDPS with 3-c-C5H9-4-MeOC6H3MgBr, followed by several transformations, afforded a tumor necrosis factor inhibitor possessing a Ph-acetylene moiety. The inhibitor was also synthesized from phenylacetylene phosphate PhCCCH(OP(O)(OEt)2)CH2CH2OTBDPS. Furthermore, the substitution of phosphates derived from TMSCCCH(OH)CH3 and TMSCCCH(OH)-i-Pr with 3-F-4-PhC6H3MgBr gave the corresponding substitution products, which were transformed to flurbiprofen and its i-Pr analogue, respectively. The copper-catalyzed substitutions in these syntheses proceeded in a regio- and stereoselective manner. This journal is
- Isogawa, Yukari,Kobayashi, Yuichi,Ogawa, Narihito,Takashima, Yuji,Tsuboi, Atsuki
-
supporting information
p. 9906 - 9909
(2021/12/07)
-
- Methods for preparation of apremilast
-
The present invention discloses a method for preparation of Apremilast. β-phthalimino vinylsulfones are reacted through the asymmetric addition reaction to form an addition product, and the drug of Apremilast can be obtained from the addition product through simple reactions. The method is a process for synthesizing Apremilast in a more efficient way.
- -
-
Page/Page column 20-21
(2021/05/19)
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- Preparation method of plant growth regulation compound sodium nitrophenolate
-
The invention relates to the field of preparation of agricultural auxiliaries, in particular to a preparation method of plant growth regulation compound sodium nitrophenolate. According to the invention, acetyl chloride is adopted to replace acetic anhydride which is a precursor to serve as a protecting group for hydroxyl acetylation, so that the acquisition difficulty of process raw materials is reduced, and the production cost of 5-nitroguaiacol sodium salt is controlled; and besides, a phase transfer catalyst is applied to the hydrolysis reaction of 5-nitroacetyl guaiacol, so that the hydrolysis of the product can be effectively promoted, the yield of the hydrolysis reaction is greatly improved, and the overall yield of the 5-nitroguaiacol sodium salt is further improved. The prepared 5-nitroguaiacol sodium salt has the advantage of low cost, and as a main effective component of the compound sodium nitrophenolate, the 5-nitroguaiacol sodium salt can improve the market competitiveness of the compound sodium nitrophenolate product, avoid the behavior that the drug effect of the compound sodium nitrophenolate product is reduced due to the fact that the cost of the 5-nitroguaiacol sodium salt is high and the ratio is reduced by bad manufacturers, and make contribution for promoting the benign development of the market.
- -
-
Paragraph 0025-0087
(2021/08/06)
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- Direct Acetoxylation of Arenes
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Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
- Hong Nguyen, Thi Anh,Hou, Duen-Ren
-
supporting information
p. 8127 - 8131
(2021/08/23)
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- Method for promoting acylation of amine or alcohol by carbon dioxide
-
The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
- -
-
Paragraph 0034-0035
(2021/05/29)
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- Method for preparing acetovanillone and application of acetovanillone
-
The invention provides a method for preparing acetovanillone and an application of acetovanillone. Specifically, guaiacol is used as a raw material to react with acetyl chloride to generate ester, andthen the ester reacts with lewis acid such as AlCl3 under the catalysis of the lewis acid to generate acetovanillone. The method has the advantages of mild reaction conditions, high raw material conversion rate and simple process flow, and is suitable for large-scale industrial production.
- -
-
Paragraph 0040-0047
(2020/04/02)
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- Preparation method and application of apocynin and derivatives of apocynin
-
The invention belongs to the technical field of chemical biology, and particularly relates to a preparation method of apocynin and derivatives of the apocynin and an application of the apocynin and the derivatives of the apocynin in skin care products. The apocynin and the derivatives of the apocynin provided by the invention can promote collagen synthesis, help skin damage repair, and can be usedin the skin care products.
- -
-
Paragraph 0041; 0049-0052
(2020/01/12)
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- Highly ordered columnar superlattice nanostructures with improved charge carrier mobility by thermotropic self-assembly of triphenylene-based discotics
-
A series of triphenylene esters with two ester groups at 2,3-, 2,7-, 2,6- and 3,6- substituent positions was successfully synthesized and fully investigated. Their self-assembly properties were exhaustively examined by DSC, POM, 1DXRD, 2DXRD, SAXS, TEM methods together with EDM and ESP calculations. It was unexpected that the 3,6-substituted triphenylene ester T5E36 formed an uncommonly helical hexagonal columnar superlattice structure made up of 91 right-handed helixes with a pitch of 60.3 ?. This helical superlattice structure was further studied by using transmission electron microscopy and the diameter of the T5E36 particles was found to be at the nanometer scale. Ultimately, the bipolar charge carrier mobility was measured by the time-of-flight method to be in the order of 10-1 cm2 V-1 s-1. The formation of this helical superlattice nanostructure no doubt improved their electronic properties and made them more attractive in organic electronics.
- Bi, Jingze,Wu, Hao,Zhang, Zhenhu,Zhang, Ao,Yang, Huanzhi,Feng, Yuwen,Fang, Yi,Zhang, Lina,Wang, Zhengran,Qu, Wentao,Liu, Feng,Zhang, Chunxiu
-
supporting information
p. 12463 - 12469
(2019/10/28)
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- Asymmetric Synthesis of β-Aryl β-Imido Sulfones Using Rhodium Catalysts with Chiral Diene Ligands: Synthesis of Apremilast
-
A chiral rhodium(I)-diene catalyst enabled the one-step synthesis of β-aryl β-imido sulfones under mild reaction conditions. By selection of the chiral diene ligand L1a or L2, each enantiomer of the chiral β-aryl β-imido sulfone target can be accessed with high stereoselectivity. Demonstration of the scope of the reaction, which includes the synthesis of an N-protected chiral β-amino β-phenyl sulfone, culminated with the efficient synthesis of the heteroatom-rich active pharmaceutical ingredient apremilast.
- Syu, Jin-Fong,Gopula, Balraj,Jian, Jia-Hong,Li, Wei-Sian,Kuo, Ting-Shen,Wu, Ping-Yu,Henschke, Julian P.,Hsieh, Meng-Chi,Tsai, Ming-Kang,Wu, Hsyueh-Liang
-
supporting information
p. 4614 - 4618
(2019/06/27)
-
- Efficient preparation method of 2'-hydroxyacetophenone compounds
-
The invention discloses an efficient preparation method of 2'-hydroxyacetophenone compounds. The method comprises the following steps: substituted phenol and acetic anhydride in a molar ratio of 1:(1-1.1) is subjected to a reaction at 130-150 DEG C in the absent of a solvent, acetic acid substituted phenyl ester as shown in the formula is generated, and acetic acid and acetic acid substituted phenyl ester are separated by rectification; prepared acetic acid substituted phenyl ester is subjected to a transposition reaction under the action of a catalyst in an organic solvent at the temperatureof 50-120 DEG C, and 2'-hydroxyacetophenone compounds as shown in the formula are generated; filtering is performed to remove the catalyst after the reaction is finished, the solvent is removed by evaporation, and the 2'-hydroxyacetophenone compounds are prepared by rectification under vacuum, wherein the catalyst is phosphomolybdic acid, phosphotungstic acid, silicotungstic acid or a mixture of the acid. The preparation method has mild conditions and simple flow, and is environmentally friendly and suitable for industrial production, selectivity is high, and ortho-position selectivity is as high as 99.5%.
- -
-
Paragraph 0034-0036
(2019/05/08)
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- Na 2 CO 3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
-
Inorganic base-catalyzed O-acylation of phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using ?-Na 2 CO 3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.
- Zhou, Xiao-Yu,Chen, Xia
-
supporting information
p. 2321 - 2325
(2018/10/20)
-
- Synthesis and anti-inflammatory activity of isoquebecol
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We report here the synthesis of isoquebecol, an unprecedented constitutional isomer of quebecol, a polyphenolic compound discovered in maple syrup. The methodology used to prepare isoquebecol involves, as key steps, the formation of a dibromoalkene from an α-ketoester precursor, followed by a double Suzuki-Miyaura reaction. The anti-inflammatory activity of isoquebecol was studied on macrophage cells by monitoring its ability to inhibit LPS-induced IL-6 secretion. Results show that this new compound has an improved bioactivity over that of its natural isomer. Precursors and derivatives of quebecol, isoquebecol and model analog 2,3,3-triphenylpropanol were also prepared and tested in this study. Comparison between the three series of compounds led to establishing new SARs concerning the aryl ring substitution pattern on the triarylpropanol scaffold and substructure functionalization.
- Cardinal, Sébastien,Paquet-C?té, Pierre-Alexandre,Azelmat, Jabrane,Bouchard, Corinne,Grenier, Daniel,Voyer, Normand
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p. 2043 - 2056
(2017/03/23)
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- Regioselective Baeyer-Villiger oxidation of lignin model compounds with tin beta zeolite catalyst and hydrogen peroxide
-
Lignin depolymerization represents a promising approach to the sustainable production of aromatic molecules. One potential approach to the stepwise depolymerization of lignin involves oxidation of the benzylic alcohol group in β-O-4 and β-1 linkages, followed by Baeyer-Villiger oxidation (BVO) of the resulting ketones and subsequent ester hydrolysis. Towards this goal, BVO reactions were performed on 2-adamantanone, a series of acetophenone derivatives, and lignin model compounds using a tin beta zeolite/hydrogen peroxide biphasic system. XRD, 119Sn MAS NMR spectroscopy, DRUVS and XPS were used to determine tin speciation in the catalyst, the presence of both framework Sn and extra framework SnO2 being inferred. Conversion of ketones to BVO products was affected by electron donation as well as steric hindrance, 4′-methoxyacetophenone affording the highest yield of ester (81%). As the size and complexity of the ketone increased, excess hydrogen peroxide was typically needed for successful BVO. Yields of ester products derived from β-O-4 and β-1 lignin models were modest due to the formation of polymeric material stemming from direct ring hydroxylation.
- Jennings, John A.,Parkin, Sean,Munson, Eric,Delaney, Sean P.,Calahan, Julie L.,Isaacs, Mark,Hong, Kunlun,Crocker, Mark
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p. 25987 - 25997
(2017/07/07)
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- Ligand-Promoted Palladium-Catalyzed C?H Acetoxylation of Simple Arenes
-
The palladium-catalyzed C?H oxidation of simple arenes is an attractive strategy to obtain phenols, which have many applications in the fine chemicals industry. Although some advances have been made in this research area, low reactivity and selectivity are, in general, observed. This report describes a new catalytic system for the efficient C?H acetoxylation of simple arenes based on Pd(OAc)2 and a pyridinecarboxylic acid ligand.
- Valderas, Carolina,Naksomboon, Kananat,Fernández-Ibá?ez, M. ángeles
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p. 3213 - 3217
(2016/10/24)
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- Synthesis and biological evaluation of phenoxyacetic acid derivatives as novel free fatty acid receptor 1 agonists
-
Free fatty acid receptor 1 (FFA1) is a new potential drug target for the treatment of type 2 diabetes because of its role in amplifying glucose-stimulated insulin secretion in pancreatic β-cell. In the present studies, we identified phenoxyacetic acid derivative (18b) as a potent FFA1 agonist (EC50 = 62.3 nM) based on the structure of phenylpropanoic acid derivative 4p. Moreover, compound 18b could significantly improve oral glucose tolerance in ICR mice and dose-dependently reduced glucose levels in type 2 diabetic C57BL/6 mice without observation of hypoglycemic side effect. Additionally, compound 18b exhibited acceptable PK profiles. In summary, compound 18b with ideal PK profiles exhibited good activity in vitro and in vivo, and might be a promising drug candidate for the treatment of diabetes mellitus.
- Wang, Xuekun,Zhao, Tianxiao,Yang, Baowei,Li, Zheng,Cui, Jian,Dai, Yuxuan,Qiu, Qianqian,Qiang, Hao,Huang, Wenlong,Qian, Hai
-
p. 132 - 140
(2015/02/18)
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- Hydrogenolysis of a γ-Acetylated Lignin Model Compound with a Ruthenium-Xantphos Catalyst
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Catalytic hydrogenolysis of a γ-acetylated dimer lignin model compound is effected using a Ru-xantphos catalyst. Mechanistic investigations show mono-aryl degradation products are generated from the β-O-4 substrate as well as a terminal alkene ketone dimer (bis-aryl) that further dimerizes to a tetra-aryl product. Preliminary results using an acetylated kraft lignin as a substrate are also discussed. Graphical Abstract: [Figure not available: see fulltext.]
- Wu, Adam,Lauzon, Jean Michel,James, Brian R.
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p. 511 - 518
(2015/08/04)
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- Chelating Bis-N-heterocyclic Carbene-Palladium(II) Complexes for Oxidative Arene C-H Functionalization
-
Bis-N-heterocyclic carbene (NHC)-chelated palladium(II) complexes have been synthesized, characterized fully including single-crystal X-ray structural analyses, and utilized for the first time toward catalytic oxidative C-H functionalization of arenes with PhI(OAc)2 and N-bromosuccinimide. (Figure Presented).
- Desai, Sai Puneet,Mondal, Moumita,Choudhury, Joyanta
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p. 2731 - 2736
(2015/06/30)
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- The first vinyl acetate mediated organocatalytic transesterification of phenols: A step towards sustainability
-
The present report outlines our efforts toward a simple yet elegant protocol for O-acylation of a wide variety of phenols. This highly enabling and solventless method relies on vinyl acetate as an innocuous acyl donor and DABCO as an organocatalyst. Operational simplicity, excellent yields, higher and faster conversion rates without excess reagents, a simple workup and essentially no need of columns are some of the salient features of the reported protocol.
- Kumar, Manoj,Bagchi, Sourav,Sharma, Anuj
-
supporting information
p. 8329 - 8336
(2015/11/10)
-
- Copper-catalyzed Z-selective semihydrogenation of alkynes with hydrosilane: A convenient approach to cis-alkenes
-
A copper catalyst generated in situ from widely available copper salt and imidazolium salt in the presence of t-BuOK showed high efficiency for the semihydrogenation of a wide range of internal and terminal alkynes to their corresponding alkenes without obvious over-reduction. Functional groups, such as hydroxyl, nitro, halides, and amino, etc. were tolerated. The Z/E ratios of the obtained alkenes were generally >99%. Finally, semireduction of bulky alkynes also went smoothly.
- Wang, Guang-Hui,Bin, Huai-Yu,Sun, Miao,Chen, Shu-Wei,Liu, Ji-Hong,Zhong, Chong-Min
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p. 2175 - 2179
(2014/03/21)
-
- Negishi cross-coupling reaction as a route to isocombretastatins
-
A series of isocombretastatins A has been synthesized by a new method based on the Negishi cross-coupling reaction in 19-84% yields. Five of the synthesized compounds exhibit high cytotoxic activity in nanomolar concentrations (IC50 = 1-100 n) towards Jurkat, K562, Colo357, and A549 cell lines. Georg Thieme Verlag Stuttgart · New York.
- Malysheva, Yulia B.,Buchvalova, Svetlana Y.,Svirshchevskaya, Elena V.,Fokin, Valery V.,Fedorov, Alexey Y.
-
supporting information
p. 1772 - 1776
(2013/09/12)
-
- Steric control of site selectivity in the Pd-catalyzed C-H acetoxylation of simple arenes
-
This report describes the use of an oxidant and a ligand to control site selectivity in the Pd(OAc)2-catalyzed C-H acetoxylation of simple arenes. The use of MesI(OAc)2 as the terminal oxidant in combination with acridine as the ligand results in primarily sterically controlled selectivity. In contrast, with Pd(OAc)2 as the catalyst and PhI(OAc)2 as the oxidant, electronic effects dominate the selectivity of arene C-H acetoxylation.
- Cook, Amanda K.,Emmert, Marion H.,Sanford, Melanie S.
-
supporting information
p. 5428 - 5431
(2013/11/19)
-
- Palladium-catalyzed acetoxylation of arenes by novel sulfinyl n-heterocyclic carbene ligand complexes
-
A series of novel ligands based on N-heterocyclic carbene and sulfoxide functionalities have been prepared and characterized. Pd(II) complexes have been synthesized by transmetalation from the corresponding NHC-Ag derivatives, and their behavior as catalysts has been studied in arene C-H bond oxidative activation. Studies conducted toward the elucidation of the reaction mechanism of the acetoxylation suggest a C-H activation step at Pd(IV) rather than Pd(II) intermediates.
- Tato, Francisco,Garcia-Dominguez, Andres,Cardenas, Diego J.
-
supporting information
p. 7487 - 7494
(2014/04/03)
-
- Asymmetric synthesis of enantiomerically pure zingerols by lipase-catalyzed transesterification and efficient synthesis of their analogues
-
The achiral zingerone 1, readily available from ginger, can be easily transformed into chiral derivatives. Zingerol 2, a reduced product of zingerone 1 is expected to be an important new medicinal lead compound. We have achieved a concise synthesis of optically active zingerol (R)-2 and (S)-2 by the lipase-catalyzed stereoselective transesterification of racemic 2. Under the optimized conditions, a lipase from Alcaligenes sp. (Meito QLM) and vinyl acetate in i-Pr2O or hexane at 35 C within 1 h gave the alcohol (S)-2 and the acetate (R)-9 with high enantioselectivity without producing acetylated by-products. Since optically active (S)-2 and (R)-9 were obtained through lipase-catalyzed transesterification, other enantiomerically pure novel compounds could all be synthesized.
- Kitayama, Takashi,Isomori, Sachiko,Nakamura, Kaoru
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p. 621 - 627
(2013/07/19)
-
- New method of synthesis and biological evaluation of some combretastatin A-4 analogues
-
A series of novel combretastatin A-4 analogues was synthesized in 36-64% yields by Negishi cross-coupling reaction under mild conditions. The prepared compounds exhibit good cytotoxicity against HBL100 epithelial cell lines (IC50=0.022-10.31 ). Georg Thieme Verlag Stuttgart · New York.
- Malysheva, Yulia B.,Combes, Sebastien,Fedorov, Alexey Yu.,Knochel, Paul,Gavryushin, Andrei E.
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supporting information; experimental part
p. 1205 - 1208
(2012/06/29)
-
- Iron-doped single-walled carbon nanotubes as new heterogeneous and highly efficient catalyst for acylation of alcohols, phenols, carboxylic acids and amines under solvent-free conditions
-
Iron-doped single-walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent-free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi
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experimental part
p. 426 - 442
(2011/04/15)
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- Highly efficient and versatile acetylation of alcohols, phenols and amines catalyzed by methylenediphosphonic acid (MDP) under solvent-free conditions
-
Methylenediphosphonic Acid (MDP) was found to be a simple, cheap and reusable heterogeneous catalyst for the acetylation of structurally diverse alcohols, phenols and amines with acetic anhydride under solvent-free conditions at room temperature. This method showed preferential selectivity for the acetylation of the amino group in the presence of hydroxyl group. The method is very mild and the yields were in excellent.
- Xie, Minhao,Wang, Hongyong,Wu, Jun,He, Yongjun,Liu, Yaling,Zou, Pei
-
experimental part
p. 884 - 886
(2012/04/23)
-
- Synthesis of 1-[3-(Cyclopentyloxy)-4-methoxyphenyl]cyclopentanol as potential phosphodiesterase-4 inhibitor
-
The enzyme phosphodiesterase-4 (PDE4) plays a key role in many physiological or pathological processes in mammalian organs, where its inhibition increases cyclic adenosine monophosphate (cAMP) causing benefits in many diseases or conditions. The aim of this study is to synthesize 1-(3-(cyclopentyloxy)-4-methoxyphenyl)cyclopentanol (6) as potential phosphodiesterase-4 inhibitor. Starting from 2- methoxy phenol (1), 4-bromo-2-(cyclopentyloxy)-1-methoxybenzene (5) was synthesized in good yields. 1-[3-(Cyclopentyloxy)-4- methoxyphenyl]cyclopentanol (6) was prepared from 5 using two different methods.
- Yahya-Meymandi,Mohammadi Ziarani,Shafiee,Foroumadi
-
experimental part
p. 4008 - 4010
(2012/01/13)
-
- Alkoxyl- and carbon-centered radicals as primary agents for degrading non-phenolic lignin-substructure model compounds
-
Lignin degradation by white-rot fungi proceeds via free radical reaction catalyzed by oxidative enzymes and metabolites. Basidiomycetes called selective white-rot fungi degrade both phenolic and non-phenolic lignin substructures without penetration of extracellular enzymes into the cell wall. Extracellular lipid peroxidation has been proposed as a possible ligninolytic mechanism, and radical species degrading the recalcitrant non-phenolic lignin substructures have been discussed. Reactions between the non-phenolic lignin model compounds and radicals produced from azo compounds in air have previously been analysed, and peroxyl radical (PR) is postulated to be responsible for lignin degradation (Kapich et al., FEBS Lett., 1999, 461, 115-119). However, because the thermolysis of azo compounds in air generates both a carbon-centred radical (CR) and a peroxyl radical (PR), we re-examined the reactivity of the three radicals alkoxyl radical (AR), CR and PR towards non-phenolic monomeric and dimeric lignin model compounds. The dimeric lignin model compound is degraded by CR produced by reaction of 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH), which under N2 atmosphere cleaves the α-β bond in 1-(4-ethoxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol to yield 4-ethoxy-3-methoxybenzaldehyde. However, it is not degraded by the PR produced by reaction of Ce4+/tert-BuOOH. In addition, it is degraded by AR produced by reaction of Ti3+/tert-BuOOH. PR and AR are generated in the presence and absence of veratryl alcohol, respectively. Rapid-flow ESR analysis of the radical species demonstrates that AR but not PR reacts with the lignin model compound. Thus, AR and CR are primary agents for the degradation of non-phenolic lignin substructures.
- Ohashi, Yasunori,Uno, Yukiko,Amirta, Rudianto,Watanebe, Takahito,Honda, Yoichi,Watanabe, Takashi
-
experimental part
p. 2481 - 2491
(2011/05/14)
-
- Total synthesis of "Aliskiren": The first renin inhibitor in clinical practice for hypertension
-
We report a "macrocycle route" toward aliskiren, a drug presently marketed for the treatment of hypertension, using a highly stereocontrolled approach starting from a common "isopropyl chiron". Highlights of the synthesis include a challenging RCM reaction to produce a nine-membered unsaturated lactone, a highly stereoselective catalytic Du Bois aziridination, and a regio- and diastereoselective aziridine ring-opening to a vicinal amino alcohol.
- Hanessian, Stephen,Guesne, Sebastien,Chenard, Etienne
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supporting information; scheme or table
p. 1816 - 1819
(2010/09/16)
-
- Synthesis of amide group containing triphenylene derivatives as discotic liquid crystals and organic gelators
-
Intermolecular hydrogen bond is an efficient way to anchor columnar assembly of discotic liquid crystals, and would result in more ordered columnar mesphase and faster charged carrier mobility. In this report, a series of peripheral functionalized triphenylene derivatives, C18H 6(OC6H13)4(OCH2CONHR) 2, which contains amide groups at the 2,7-positions, have been synthesized. The polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results showed that these compounds exhibit hexagonal columnar mesophases. The triphenylene derivatives gelate in the solution of octane, petroleum ether, cyclohexane and p-xylene and form stable organic gels. The xerogels formed from organic solvents were analyzed by scanning electron microscope (SEM) and showed fiber-like or sponge-like morphology. It is demonstrated that intermolecular hydrogen bonds stabilize the columnar molecular organization and assembly in mesomorphic state and organic gel. Copyright Taylor & Francis Group, LLC.
- Bai,Zhao,Hu,Wang,Shimizu
-
experimental part
p. 60 - 76
(2011/08/07)
-
- Counterattack mode differential acetylative deprotection of phenylmethyl ethers: Applications to solid phase organic reactions
-
A counterattack protocol for differential acetylative cleavage of phenylmethyl ether has been developed. The phenylmethyl moiety is liberated as benzyl bromide that is isolated and reused providing advantages in terms of waste minimization/utilization and atom economy. The applicability of this methodology has been extended for solid phase organic reactions with the feasibility of reuse of the solid support.
- Chakraborti, Asit K.,Chankeshwara, Sunay V.
-
experimental part
p. 1367 - 1370
(2009/07/04)
-
- Electrophilic components in the electrochemical acetoxylation of substituted arenes
-
The mechanism of anodic acetoxylation of substituted arenes under conditions of undivided galvanostatic electrolysis in MeCN containing acetate is suggested and an important role of electrophilic components (AcOH or ZnCl2) catalyzing transformation of intermediate ipso-acetoxylated polysubstituted arenonium cations to corresponding ortho-acetoxylated arenonium cations, which give acetoxylation products after deprotonation, is experimentally proved.
- Burasov, Alexander V.,Petrosyan, Vladimir A.
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p. 196 - 197
(2008/12/22)
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- Kumada-Corriu cross coupling route to the anti-cancer agent combretastatin A-4
-
A short and efficient synthesis of the anticancer agent combretastatin A-4 was accomplished from inexpensive starting materials using the iron-catalyzed cross-coupling of a Grignard reagent and a bromostilbene as the key step. Copyright Taylor & Francis Group, LLC.
- Camacho-Davila, Alejandro A.
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p. 3823 - 3833
(2008/12/23)
-
- SO42-/SnO2: Efficient, chemoselective, and reusable catalyst for acylation of alcohols, phenols, and amines at room temperature
-
SO42-/SnO2 was employed for the acylation of a variety of alcohols, phenols, and amines under solvent-free conditions at room temperature. This method showed preferential selectivity for acetylation of the amino group in the presence of a hydroxyl group. The reported method is simple, mild, and environmentally viable, using several other acid anhydrides at room temperature. Copyright Taylor & Francis Group, LLC.
- Satam, Jitendra R.,Gawande, Manoj B.,Deshpande, Sameer S.,Jayaram, Radha V.
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p. 3011 - 3020
(2008/02/12)
-
- 4,5-Diaryl-1H-pyrrole-2-carboxylates as combretastatin A-4/lamellarin T hybrids: Synthesis and evaluation as anti-mitotic and cytotoxic agents
-
The 4,5-diarylated-1H-pyrrole-2-carboxylates 3-8 have each been prepared as hybrids of the potent anti-mitotic agent combretastatin A-4 (1) and the similarly active marine alkaloid lamellarin T (2). The key steps involved selective lithium-for-halogen exchange at C5 within the N-PMB protected 4,5-dibromopyrrole 22 and Negishi cross-coupling of the derived zincated species with the relevant aryl iodide. The ensuing 5-aryl-4-bromopyrrole then engaged in Suzuki-Miyaura cross-coupling with the appropriate arylboronic acid to give the 4,5-diarylated pyrroles 4, 6 and 8. TFA-promoted removal of the N-PMB group within these last compounds then gave the N-unsubstituted congeners 3, 5 and 7. Compounds 3-8 have all been evaluated for their anti-mitotic and cytotoxic properties and two of them, 3 and 5, display useful activities although they are less potent than combretastatin A-4. Crown Copyright
- Banwell, Martin G.,Hamel, Ernest,Hockless, David C.R.,Verdier-Pinard, Pascal,Willis, Anthony C.,Wong, David J.
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p. 4627 - 4638
(2007/10/03)
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- Facile and regioselective dealkylation of alkyl aryl ethers using niobium(V) pentachloride
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A simple and facile method for the cleavage of carbon-oxygen bonds promoted by niobium pentachloride(V) is described. Excellent yields and regioselectivities were observed with various alkyl aryl ethers to give the phenols. NMR studies revealed the formation of monoaryloxy niobium salt(V), and a neighboring-group effect may play a significant role in the regioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Sudo, Yukinori,Arai, Shigeru,Nishida, Atsushi
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p. 752 - 758
(2007/10/03)
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- Co-catalyzed reductive cyclization of azido and cyano substituted α,β-unsaturated esters with NaBH4: enantioselective synthesis of (R)-baclofen and (R)-rolipram
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Sodium borohydride in combination with a catalytic amount of CoCl2 has been found to be an excellent catalytic system in reductive cyclizations of suitably substituted azido and cyano groups of α,β-unsaturated esters to afford γ and δ-lactams in high yields. The process has been demonstrated for the enantioselective synthesis of (R)-baclofen, (R)-rolipram, and (R)-4-fluorophenylpiperidinone, a key intermediate for (-)-paroxetine.
- Paraskar, Abhimanyu S.,Sudalai, Arumugam
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p. 4907 - 4916
(2007/10/03)
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- Novel synthesis, reactivity, and stereochemistry of substituted 3-trifluoromethyl- and 3-perfluoroalkyl-3-phenoxyprop-2-enal
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Substituted 3-phenoxy-3-perfluoroalkylprop-2-enals 3a-s are synthesized in high yields starting from a gem-iodoacetoxy derivative 1 and phenoxides 2. Then efficient syntheses of push-pull derivatives 4, 5, 8a,b, and nonconjugated analogues 6 and 7 illustrate the synthetic potentialities of 3. Stereochemical studies of these perfluoroalkyl-containing trisubstituted olefinic derivatives 3-8b revealed that the 4JCF coupling constant observed in the 13C NMR spectra was crucial in the determination of their configurations and conformations in solution. The solvent polarity effect on the stereochemistry of push-pull compounds 3-5 and 8a,b was studied. Unusual significant medium polarity effect on the stereochemistry of imino enol ether derivative 4 was observed.
- El Kharrat, Salem,Laurent, Philippe,Blancou, Hubert
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p. 6742 - 6752
(2007/10/03)
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- Synthesis and biological activity of the tea catechin metabolites, M4 and M6 and their methoxy-derivatives
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Syntheses are reported for metabolites M4 (1) and M6 (2) of the green tea polyphenols epicatechin (EC) and epigallocatechin (EGC) and their gallate derivatives. Several methoxy-derivatives of 1 and 2 were also prepared. Compounds 1 and 2 were evaluated for growth inhibitory activity against a panel of immortalized and malignant human cell lines with 1 being the more active compound. The possible antiinflammatory activity of 1 and its trimethoxy derivative was also evaluated. Neither compound inhibited the release of arachidonic acid, although 1 inhibited NO production by 50% at 20 μM.
- Lambert, Joshua D.,Rice, Joseph E.,Hong, Jungil,Hou, Zhe,Yang, Chung S.
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p. 873 - 876
(2007/10/03)
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- Iodine as an extremely powerful catalyst for the acetylation of alcohols under solvent-free conditions
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Iodine was found to promote quantitative acetylation of alcohols in a very short time with an equimolar amount of acetic anhydride under solvent-free conditions at room temperature.
- Phukan, Prodeep
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p. 4785 - 4787
(2007/10/03)
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- Iodinated biaryls synthesized by the direct dehydrodimerization of iodoarenes using phenyliodine(III) bis(trifluoroacetate) (PIFA)
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Multiply iodinated biaryls can be prepared in yields up to 75% by direct oxidative coupling reaction of the iodinated arenes. The PIFA-mediated dehydrodimerization is superior to all other known methods. The developed protocol is reliable and easy to perform.
- Mirk, Daniela,Willner, Alexander,Froehlich, Roland,Waldvogel, Siegfried R.
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p. 675 - 681
(2007/10/03)
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- Mg(ClO4)2 as a powerful catalyst for the acylation of alcohols under solvent-free conditions
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A trace amount of magnesium perchlorate (from 0.1 mol% to 1 mol%) is able to promote quantitative acylation, with anhydrides, of a large variety of functionalized alcohols in short times, at room temperature and under solvent-free conditions.
- Bartoli, Giuseppe,Bosco, Marcella,Dalpozzo, Renato,Marcantoni, Enrico,Massaccesi, Massimo,Rinaldi, Samuele,Sambri, Letizia
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- Isopropoxy as a masked hydroxy group in aryl oxidative coupling reactions
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Mono- and dihydroxy substituted triphenylenes have been prepared in a one-pot biphenyl/phenyl oxidative coupling reaction, in which isopropoxy acts as a masking/protecting group.
- Bushby,Lu
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p. 763 - 767
(2007/10/03)
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- Cyclization pathways of a (Z)-stilbene-derived bis(orthoquinone monoketal)
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Lead tetraacetate mediated oxidation of a (Z)-bisphenolic stilbene derivative affords a bis(orthoquinone monoketal) product. Thermolysis studies of this highly unsaturated dione reveal that sigmatropic hydrogen shifts, followed by either of two distinct solvolytic ring closures, constitute the predominate reaction pathways under heating. No evidence for a desired 6π electron electrocyclization was forthcoming.
- Feldman, Ken S.
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p. 4983 - 4990
(2007/10/03)
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- Retention behavior of compounds with active hydrogen atoms and their acetylated derivatives in reversed-phase HPLC
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In view of poor interlaboratory reproducibility of retention indices I in reversed-phase high-performance liquid chromatography, not the indices themselves but their differences for reactants and products of interaction with various reagents can be used to identify compounds with active hydrogen atoms. For acetylated derivatives of phenols and aromatic amines, the quantity ?I = I(ArXH) -I(ArXCOCH3), where X = O or NH. has statistically significant distinguishable values of 126 ± 15 and 70 ± 20, respectively. The additivity of the parameters ?I is first revealed for the polyfunctional compounds of these classes that are incapable of intramolecular hydrogen bonding. Abnormal ?I values and deviations from the additivity rule are observed only for substances with intramolecular hydrogen bonding. This finding can be used to confirm the presence of relevant structural units in molecules.
- Zenkevich,Kosman
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p. 1173 - 1176
(2007/10/03)
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- Triphenylene-based discotic-liquid-crystalline polymers: A universal, rational synthesis
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A simple, regiospecific synthesis of main-chain, triphenylene-based discotic-liquid-crystalline polymers is described in which the key step is the assembly of the triphenylene nucleus through the oxidative coupling of phenyl and biphenyl residues. Hence, treatment of a mixture of 3,3′-bis(hexyloxy)-4,4′-dimethoxybiphenyl and 1,2-bis(hexyloxy)benzene with ferric chloride in dichloromethane followed by a reductive, methanol workup gives 2,7-dimethoxy-3,6,10,11-tetrakis(hexyloxy)triphenylene, 7. The 2,7-linked main-chain polymer 8 is produced by demethylation and condensation with 1,11-dibromoundecane, has average molecular weight 24 000, and Dh mesophase range of 98-118 °C. The 3,6- and 2,3-linked polymers were prepared in a similar manner.
- Boden, Neville,Bushby, Richard J.,Cammidge, Andrew N.
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p. 924 - 926
(2007/10/02)
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- Facile Formation of o- and p-Tropoquinone Mono- and Bisacetals by Anodic Oxidation of 2,3-, 2,5-, 2,7-, and 4,5-Dimethoxytropones
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o- and p-Tropoquinone mono- and bisacetals (tetramethoxycycloheptadienones) were prepared from 2,3-, 2,5-, 2,7-, and 4,5-dimethoxytropones by means of anodic oxidations in practical yields.Cerium(IV) salt oxidations of dimethoxytropones afforded a mixture of products i.e., a hydrolysis product and/or a methanol adduct of tropoquinone bisacetals.By treating with sulfuric acid in a mixture of acetic acid and acetic anhydride, 4,4,7,7- and 2,2,7,7-tetramethoxycycloheptadienones gave the Thiele-type reaction products with a high positional selectivity.Similarly, 2-bromo-7-methoxytropone was anodically oxidized to 4,4,7,7-tetramethoxycycloheptadienone and its 2-bromo derivative.The mechanism of the reaction is also discussed in detail.
- Mori, Akira,Kubota, Tadahiko,Takeshita, Hitoshi
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p. 3965 - 3972
(2007/10/02)
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- Direct Formations of o-Tropoquinone Bisacetals from 2,3- and 2,7-Dimethoxytropones and p-Tropoquinone Bisacetals from 2-Bromo-7-methoxytropone by the Anodic Oxidation
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Anodic oxidation of 2,7- and 2,3-dimethoxytropones gave the corresponding isomeric o-tropoquinone bisacetals, 2,2,7,7-tetramethoxycyclohepta-3,5-dienone and 2,2,3,3-tetramethoxycyclohepta-4,6-dienone in good yields.By H2SO4-treatment in AcOH-Ac2O, former afforded 4-acetoxy-2,7-dimethoxytropone, 2,5-diacetoxy-7-methoxytropone and 4,5-diacetoxy-3-methoxytropone, latter did no such product.Similar oxidation of 2-bromo-7-methoxytropone gave alternative p-tropoquinone bisacetal derivatives.
- Mori, Akira,Kubota, Tadahiko,Kasai, Seishi,Takeshita, Hitoshi
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p. 1931 - 1934
(2007/10/02)
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