- Cicindeloine from Stenus cicindeloides-isolation, structure elucidation, and total synthesis
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The new piperideine alkaloid cicindeloine (3) was isolated from the pygidial glands of the beetles Stenus cicindeloides and Stenus solutus. The structure and absolute configuration of 3 were elucidated by NMR spectroscopy and asymmetric synthesis, respect
- Mueller, Tobias,Goehl, Matthias,Lusebrink, Inka,Dettner, Konrad,Seifert, Karlheinz
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Read Online
- Tandem Conjugate addition of Silylcuprate and Benzenesulfenyl Chloride to Unsaturated Esters: Stereoselective Preparation of anti-3-Dimethylphenylsilyl-2-phenylthio Aldehydes
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Conjugate addition of dimethylphenylsilylcuprate is successful even to a 2,3-disubstituted acrylate ester and when followed by α-sulfenylation of the trapped silyl enol ether intermediate, reduction and re-oxidation gives, for example, (2SR,3RS)-(anti)-2,
- Villa, Maria-Jesus,Warren, Stuart
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Read Online
- Synthesis of lignin model compound containing a β-O-4 linkage
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Development of catalysts for efficient conversion of lignin polymer to value-added materials requires appropriately-functionalized lignin model compounds. The predominant structural feature of lignin biopolymer is an extensive network of β-O-4 linkages. A
- Mukhtar, Asma,Zaheer, Muhammad,Saeed, Muhammad,Voelter, Wolfgang
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Read Online
- Organocatalyzed [2+2] Cycloaddition Reactions between Quinone Imine Ketals and Allenoates
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A new cycloaddition reaction of quinone imine ketals (QIKs), which could be utilized to the construction of functionalized azaspirocyclics under mild conditions, is described. This transformation involved a [2+2] cycloaddition reaction between QIKs and allenoates catalyzed by DABCO, and then treatment with 1 N HCl in one-pot. The strategy could provide a practical route to access azetidine-fused spirohexadienones in good to excellent yields and with high E -selectivity.
- Liu, Teng,He, Chixian,Wang, Fan,Shen, Xiang,Li, Yongqin,Lang, Man,Li, Guijun,Huang, Chao,Cheng, Feixiang
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p. 518 - 526
(2020/10/12)
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- Catalytic asymmetric [3+2] cycloaddition of isomünchnones with methyleneindolinones
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An efficient enantioselective [3+2] cycloaddition of isomünchnones with methyleneindolinones that are generated by anin situintramolecular addition of the carbonyl group to rhodium carbenes is realized with a chiralN,N′-dioxide/Zn(ii) complex as a Lewis acid. A series of chiral oxa-bridged 3-spiropiperidines are obtained in high yields with excellent dr and excellent ee values.
- Feng, Xiaoming,Hu, Xinyue,Lin, Lili,Wang, Kaixuan,Xu, Chaoran,Zhou, Yuqiao
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supporting information
p. 8917 - 8920
(2021/09/10)
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- Substituted dienes prepared from betulinic acid – Synthesis, cytotoxicity, mechanism of action, and pharmacological parameters
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A set of new substituted dienes were synthesized from betulinic acid by its oxidation to 30-oxobetulinic acid followed by the Wittig reaction. Cytotoxicity of all compounds was tested in vitro in eight cancer cell lines and two noncancer fibroblasts. Almost all dienes were more cytotoxic than betulinic acid. Compounds 4.22, 4.30, 4.33, 4.39 had IC50 below 5 μmol/L; 4.22 and 4.39 were selected for studies of the mechanism of action. Cell cycle analysis revealed an increase in the number of apoptotic cells at 5 × IC50 concentration, where activation of irreversible changes leading to cell death can be expected. Both 4.22 and 4.39 led to the accumulation of cells in the G0/G1 phase with partial inhibition of DNA/RNA synthesis at 1 × IC50 and almost complete inhibition at 5 × IC50. Interestingly, compound 4.39 at 5 × IC50 caused the accumulation of cells in the S phase. Higher concentrations of tested drugs probably inhibit more off-targets than lower concentrations. Mechanisms disrupting cellular metabolism can induce the accumulation of cells in the S phase. Both compounds 4.22 and 4.39 trigger selective apoptosis in cancer cells via intrinsic pathway, which we have demonstrated by changes in the expression of the crucial apoptosis-related protein. Pharmacological parameters of derivative 4.22 were superior to 4.39, therefore 4.22 was the finally selected candidate for the development of anticancer drug.
- ?arek, Jan,Benická, Sandra,D?ubák, Petr,Frydrych, Ivo,Gurská, Soňa,Hajdúch, Marián,Kotulová, Jana,Li?ková, Barbora,Olejníková, Denisa,Pokorny, Jan,Urban, Milan
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- Enantioselective Rauhut–Currier Reaction with β-Substituted Acrylamides Catalyzed by N-Heterocyclic Carbenes
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β-Substituted acrylamides have low electrophilicity and are yet to be exploited in the enantioselective Rauhut–Currier reaction. By exploiting electron-withdrawing protection of the amide and moderate nucleophilicity N-heterocyclic carbenes, such substrates have been converted to enantioenriched quinolones. The reaction proceeds with complete diastereoselectivity, good yield, and modest enantioselectivity. Derivatizations are reported, as are computational studies, supporting decreased amide bond character with electron-withdrawing protection of the nitrogen.
- Pitchumani, Venkatachalam,Breugst, Martin,Lupton, David W.
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supporting information
p. 9413 - 9418
(2021/12/09)
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- Enantioselective Allenoate-Claisen Rearrangement Using Chiral Phosphate Catalysts
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Herein we report the first highly enantioselective allenoate-Claisen rearrangement using doubly axially chiral phosphate sodium salts as catalysts. This synthetic method provides access to β-amino acid derivatives with vicinal stereocenters in up to 95percent ee. We also investigated the mechanism of enantioinduction by transition state (TS) computations with DFT as well as statistical modeling of the relationship between selectivity and the molecular features of both the catalyst and substrate. The mutual interactions of charge-separated regions in both the zwitterionic intermediate generated by reaction of an amine to the allenoate and the Na+-salt of the chiral phosphate leads to an orientation of the TS in the catalytic pocket that maximizes favorable noncovalent interactions. Crucial arene-arene interactions at the periphery of the catalyst lead to a differentiation of the TS diastereomers. These interactions were interrogated using DFT calculations and validated through statistical modeling of parameters describing noncovalent interactions.
- Ellwart, Mario,Gensch, Tobias,Han, Seo-Jung,Lin, Hsin-Hui,Miró, Javier,Sigman, Matthew S.,Toste, F. Dean
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supporting information
p. 6390 - 6399
(2020/04/27)
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- Phosphine-catalyzed dearomative [3+2] annulation of 3-nitroindoles and allenoates
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The efficient phosphine-catalyzed dearomative [3+2] annulation of 3-nitroindoles with allenoates has been successfully developed, providing a facile access to cyclopenta[b]indolines with good to excellent yields and high diastereoselectivities. This strategy features mild reaction conditions, high functional group tolerance, and scalability. Additionally, the 2-nitrobenzofuran and 2-nitrobenzothiophene were good dearomative [3+2] annulation partners.
- Liu, Kui,Wang, Gang,Cheng, Shao-Jie,Jiang, Wen-Feng,He, Cheng,Ye, Zhi-Shi
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supporting information
p. 1885 - 1890
(2019/06/21)
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- Intermolecular Dehydrative Coupling and Intramolecular Cyclization of Ruthenium Vinylidene Complexes Formed from Aromatic Propynes Containing Carbonyl Functionalities
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A remarkable intermolecular dehydrative coupling reaction with the formation of a C?C bond was found for the vinylidene complex 2 a, yielding the dinuclear bisvinylidene complex 4 a. Complex 2 a containing 1-hydroxyindan moiety was first formed from the reaction of o-propynyl benzaldehyde 1 a with [Ru]–Cl ([Ru]=Cp(PPh3)2Ru) by a cyclization process. For analogous aldehyde 1 b containing an additional 1,3-dioxolane group on the aryl ring, similar intermolecular coupling yields the dinuclear bisvinylidene complex 4 b. However, the fluoro group on the aryl ring in aldehyde 1 c inhibits the coupling reaction, giving only the vinylidene complex 2 c. For the reactions of [Ru]–Cl in MeOH with compounds 1 f, 1 g and 1 h, each with a ketone functionality, cyclization gives vinylidene complexes 2 f, 2 g and 2 h, respectively. However, no similar intermolecular coupling was observed, instead, the intramolecular dehydration yields 8 f, 8 g and 8 h, respectively. In CDCl3, catalytic cyclization is observed for the o-propynylphenyl ketone 1 h with [Ru]–Cl at 50 °C giving the isochromene products 14 h. Furthermore, treatment of the o-propynylaryl α,β-unsaturated ketones 1 k–m and 1 n with [Ru]–Cl in MeOH affords the corresponding vinylidene complexes 10 k–m and 11 n each with 1-benzosuberone moiety in the presence of NH4PF6. These intramolecular cyclization products were formed by the addition of Cβ onto the terminal carbon of the alkene moiety. All these reaction products were characterized by spectroscopic methods. In addition, structures of complexes 4 a, and 10 l were confirmed by single crystal X-ray diffraction analysis.
- Chia, Pi-Yeh,Kuo, Cheng-Chen,Huang, Shou-Ling,Liu, Yi-Hong,Liu, Ling-Kang,Lin, Ying-Chih
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supporting information
p. 3885 - 3894
(2018/11/10)
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- Fluoroquinolone-methyl thiazolyl tetrazolium heterozygous derivative, preparation method and application thereof
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The invention discloses a fluoroquinolone-methyl thiazolyl tetrazolium heterozygous derivative as shown in formula I. The derivate is characterized in that pharmacophores of fluoroquinolone and methylthiazolyl tetrazolium type medicines are interconnected
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Paragraph 0093; 0095; 0096
(2019/01/16)
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- Electrochemical Dimerization of Phenylpropenoids and the Surprising Antioxidant Activity of the Resultant Quinone Methide Dimers
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A simple method for the dimerization of phenylpropenoid derivatives is reported. It leverages electrochemical oxidation of p-unsaturated phenols to access the dimeric materials in a biomimetic fashion. The mild nature of the transformation provides excellent functional group tolerance, resulting in a unified approach for the synthesis of a range of natural products and related analogues with excellent regiocontrol. The operational simplicity of the method allows for greater efficiency in the synthesis of complex natural products. Interestingly, the quinone methide dimer intermediates are potent radical-trapping antioxidants; more so than the phenols from which they are derived—or transformed to—despite the fact that they do not possess a labile H-atom for transfer to the peroxyl radicals that propagate autoxidation.
- Romero, Kevin J.,Galliher, Matthew S.,Raycroft, Mark A. R.,Chauvin, Jean-Philippe R.,Bosque, Irene,Pratt, Derek A.,Stephenson, Corey R. J.
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supporting information
p. 17125 - 17129
(2018/12/04)
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- Preparation method of 2-hydroxymethyl methyl acrylate
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The invention discloses a preparation method of 2-hydroxymethyl methyl acrylate. The method includes the steps of firstly, mixing triphenyl phosphine, a catalyst and solvent, and dropwise adding 2-methyl bromoacetate to mixed liquid for temperature raising reaction; secondly, after reaction ends, being standing still and separating phases to separate out a methylbenzene phase; thirdly, dropwise adding a sodium hydroxide aqueous solution for cooling and crystallizing; fourthly, conducting suction filtration, and rinsing a filter cake with n-heptane to prepare methoxycarbonyl methylene triphenyl phosphoric chloride, namely a Wittig reagent; fifthly, adding the Wittig reagent to water, adding a formaldehyde aqueous solution, and dropwise adding a potassium carbonate aqueous solution for reaction; sixthly, filtering out triphenyl phosphine; seventhly, adding the solvent to filtrate for extraction; eighthly, concentrating an organic phase, and conducting reduced pressure distillation after removing the solvent to obtain 2-hydroxymethyl methyl acrylate. The raw materials are easy to obtain, production cost is low, and the method is suitable for industrial production and high in product yield.
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Paragraph 0031-0033
(2017/06/02)
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- Leukotriene A4 hydrolase and cyclooxygense double target inhibitors and use thereof
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The invention discloses a double-target inhibitor for leukotriene A4 hydrolase and cyclooxygenase as well as a purpose of the double-target inhibitor. The double-target inhibitor is a compound shown in a general formula (I), wherein X1 and X2 are respectively and independently separated into hydrogen, halogen, alkyl or alkoxy; Y represents hydrogen, hydroxyl, halogen or alkyl; Z represents substituent groups at the fourth position and/or the fifth position of a benzoyl core benzene ring, and respectively represents hydrogen, halogen, amino, alkyl acylamino, alkyl substituted amino, trifluoromethyl or carboxyl alkyl acylamino; n is 2 to 4. The compound can be used for preparing medicine for treating, preventing or inhibiting inflammation such as arthritis and rheumatoid arthritis.
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Paragraph 0108; 0109; 0110
(2016/10/07)
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- DABCO-catalyzed synthesis of trifluoromethylated furans from propargyl alcohols and methyl 2-perfluoroalkynoate
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The DABCO-catalyzed reaction of propargyl alcohols with methyl 2-perfluoroalkynoate to give trifluoromethylated furans in up to 98% yield under mild conditions has been developed. The established allene-enol and control experiments indicate that the react
- Chong, Qinglei,Xin, Xiaoyi,Wang, Chunxiang,Wu, Fan,Wang, Haolong,Shi, Ji-Cheng,Wan, Boshun
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p. 2105 - 2110
(2014/04/03)
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- Titania-promoted carboxylic acid alkylations of alkenes and cascade addition-cyclizations
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Photochemical reactions employing TiO2 and carboxylic acids under dry anaerobic conditions led to several types of C-C bond-forming processes with electron-deficient alkenes. The efficiency of alkylation varied appreciably with substituents in the carboxylic acids. The reactions of aryloxyacetic acids with maleimides resulted in a cascade process in which a pyrrolochromene derivative accompanied the alkylated succinimide. The selectivity for one or other of these products could be tuned to some extent by employing the photoredox catalyst under different conditions. Aryloxyacetic acids adapted for intramolecular ring closures by inclusion of 2-alkenyl, 2-aryl, or 2-oximinyl functionality reacted rather poorly. Profiles of reactant consumption and product formation for these systems were obtained by an in situ NMR monitoring technique. An array of different catalyst forms were tested for efficiency and ease of use. The proposed mechanism, involving hole capture at the TiO2 surface by the carboxylates followed by CO2 loss, was supported by EPR spectroscopic evidence of the intermediates. Deuterium labeling indicated that the titania likely donates protons from surface hydroxyl groups as well as supplying electrons and holes, thus acting as both a catalyst and a reaction partner.
- Manley, David W.,McBurney, Roy T.,Miller, Phillip,Walton, John C.,Mills, Andrew,O'Rourke, Christopher
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p. 1386 - 1398
(2014/03/21)
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- Synthesis of labdane diterpenes galanal A and B from (+)-sclareolide
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The first chemical synthesis of galanal A and B was achieved by a concise and highly efficient pathway starting from commercially available (+)-sclareolide and features a Wittig reaction and a titanocene-mediated radical cyclization as the key steps.
- Kumar, Chebolu Naga Sesha Sai Pavan,Chein, Rong-Jie
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supporting information
p. 2990 - 2992
(2014/06/23)
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- Selective synthesis and comparative activity of olefinic isomers of 1,2-benzothiazine-1,1-dioxide carboxylates as aldose reductase inhibitors
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α,β- and β,γ-unsaturated carboxylate isomers of 1,2-benzothiazine-1,1-dioxide were selectively synthesized via the Wittig olefination reaction under various temperature conditions. At 40 °C, α,β-unsaturated esters with high Z-stereoselectivity (83-87%) we
- Parveen, Shagufta,Hussain, Saghir,Zhu, Shaojuan,Qin, Xiangyu,Hao, Xin,Zhang, Shuzhen,Lu, Jianglu,Zhu, Changjin
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p. 21134 - 21140
(2014/06/09)
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- Synthesis of 1,4-enamino ketones by [3,3]-rearrangements of dialkenylhydroxylamines
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The synthesis of 1,4-enamino ketones has been achieved through the [3,3]-rearrangement of dialkenylhydroxylamines generated from the addition of N-alkenylnitrones to electron-deficient allenes. The mild conditions required for this reaction, and the simultaneous installation of a fluorenyl imine N-protecting group as a consequence of the rearrangement, avoid spontaneous cyclization of the 1,4-enamino ketones to form the corresponding pyrroles and allow for the isolation and controlled divergent functionalization of these reactive intermediates. The optimization, scope, and tolerance of the new method are discussed with demonstrations of the utility of the products for the synthesis of pyrroles, 1,4-diones, and furans.
- Pecak, Wiktoria H.,Son, Jongwoo,Burnstine, Amy J.,Anderson, Laura L.
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supporting information
p. 3440 - 3443
(2014/07/21)
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- Catalytic asymmetric cross-dehydrogenative coupling: Activation of C-H bonds by a cooperative bimetallic catalyst system
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A cooperative bimetallic catalyst system was applied in the catalytic asymmetric cross-dehydrogenative coupling of β-ketoesters and xanthene. Various optically active xanthene derivatives bearing a quaternary stereogenic carbon center were obtained in moderate to good yields (up to 90%) with excellent enantioselectivities (up to 99% ee). Meanwhile, a transition-state model was proposed to explain the origin of the asymmetric induction.
- Cao, Weidi,Liu, Xiaohua,Peng, Ruixue,He, Peng,Lin, Lili,Feng, Xiaoming
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supporting information
p. 3470 - 3472
(2013/05/23)
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- An approach to the carbon backbone of bielschowskysin, part 1: Photocyclization strategy
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Several macrocyclization reaction attempts of highly advanced precursors toward a total synthesis of marine diterpene bielschowskysin are disclosed. Biomimetic [2+2]-photocyclization reactions were applied to construct the cyclobutane core in these intermediates, which could be accessed along scalable high-yielding reaction sequences from cheap enantiopure starting-materials. Asymmetric syntheses of various highly functionalized intermediates toward the total synthesis of bielschowskysin (1) are described. In particular a biomimetic [2+2]-photocycloaddition reaction strategy, forming the cyclobutane core, was followed by various macrocyclization reactions attempts. Copyright
- Himmelbauer, Martin,Farcet, Jean-Baptiste,Gagnepain, Julien,Mulzer, Johann
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p. 8214 - 8244
(2014/01/06)
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- NSAID-derived γ-secretase modulation requires an acidic moiety on the carbazole scaffold
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Modulation of γ-secretase activity holds potential for the treatment of Alzheimer's disease. Most NSAID-derived γ-secretase modulators feature a carboxylic acid, which may impair blood-brain barrier permeation. The structure activity relationship of 33 ca
- Zall, Andrea,Kieser, Daniel,Hoettecke, Nicole,Naumann, Eva C.,Thomaszewski, Binia,Schneider, Katrin,Steinbacher, Dirk T.,Schubenel, Robert,Masur, Stefan,Baumann, Karlheinz,Schmidt, Boris
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supporting information; experimental part
p. 4903 - 4909
(2011/10/04)
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- METHOD FOR OBTAINING CINATRINS C3 AND C1
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The present invention relates to a process for obtaining cinatrins C1 and C3 and derivatives thereof which comprises the hydroxylation of a compound of formula (III). The invention also relates to the intermediates of said synthesis
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Page/Page column 15-16
(2011/04/14)
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- 1,2-Benzothiazine 1,1-dioxide carboxylate derivatives as novel potent inhibitors of aldose reductase
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Due to the importance of aldose reductase (ALR2) as a potential drug target in the treatment of diabetic complications, there are increasing interests in design and synthesis of ALR2 inhibitors. Here, we prepared 1,2-benzothiazine 1,1-dioxide acetic acid derivatives and investigated their inhibition activity. Most of these derivatives were found to be active with IC50 values ranging from 0.11 μM to 10.42 μM, and compound 8d, 2-[2-(4-bromo-2- fluorobenzyl)-1,1-dioxido-2H-1,2-benzothiazin-4(3H)-ylidene]acetic acid, showed the most potent inhibition activity. Further, SAR and docking studies suggest that in comparison with the α,β-unsaturated derivatives, the saturated carboxylic acid derivatives had a greater binding affinity with the enzyme and thus an enhanced inhibition activity. Therefore, development of more powerful ARIs based on benzothiazine 1,1-dioxide by stereo-controlled synthesis could be expected.
- Chen, Xin,Zhang, Shuzhen,Yang, Yanchun,Hussain, Saghir,He, Minlan,Gui, Dequan,Ma, Bing,Jing, Chaojun,Qiao, Zhixin,Zhu, Changjin,Yu, Qun
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experimental part
p. 7262 - 7269
(2012/01/03)
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- Antifungal 3,5-disubstituted furanones: From 5-acyloxymethyl to 5-alkylidene derivatives
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5-Acetoxymethyl-3-(4-bromophenyl)-2,5-dihydrofuran-2-one previously described as highly antifungally active was found to provide the corresponding 5-methylene derivative via an unusual DMSO-promoted elimination of the ester group at C5 under antifungal assay conditions. Since the latter possessed nearly the same antifungal effect as that originally reported for the former, the 5-acetoxymethyl furanone just served as a precursor of the actual antifungally active species. A few series of compounds with alkyloxy, aryloxy and alkylidene substituents at C5 of the parent furanone structure were therefore prepared and evaluated. In line with the ease of elimination of the substituent from C5, low activities of the 5-alkoxy compounds were observed. On the other hand, their 5-aryloxymethyl congeners were found to be capable of liberating the antifungally active 5-methylene furanone into the testing medium. The antifungal effect of the 5-alkylidene derivatives was highly sensitive to substitution of the alkylidene moiety; a substituent in the allylic position was necessary for a compound to retain high activity. Parallel evaluation of cytostatic activity showed moderate activities of the antifungally active derivatives against HeLa S3 and CCRF-CEM lines. Cell cycle analysis of CCRF-CEM cells following the treatment with 5-methylene-3-(4-bromophenyl)-2,5-dihydrofuran-2-one revealed that this compound is a necrotic agent.
- ?enel, Petr,Tichotová, Lucie,Votruba, Ivan,Buchta, Vladimír,?pulák, Marcel,Kune?, Ji?í,Nobilis, Milan,Krenk, Ond?ej,Pour, Milan
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experimental part
p. 1988 - 2000
(2010/05/18)
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- Thermal decomposition of triphenylphosphonium alkyl ester salts
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In thermolyses of molten triphenylphosphonium alkyl ester bromides and chlorides, alkyl = methyl, ethyl, isopropyl, at 130 and 225°C, initial attack of the halide ion on the methyl group gives the methyl halide and ylid 1, Ph3P = CH2, which can be methylated, or is protonated by the phosphonium salt with transylidation giving Ph3P+-CH3X-, X = Br, Cl. The initial reactions of the ethyl or isopropyl esters are with the halide ion, X-, as a base giving ylid, 1, which can be protonated by HX or by transylidation. The t-butyl ester generates Ph3P+-CH3X-but no products of transylidation. The first-formed ylid1, can be trapped by reactive alkyl and acyl halides, and the transient ylidic esters decompose thermally to triphenyl phosphine oxide, Ph3P = O, react further with unreacted phosphonium ester, or are trapped by added aldehyde in a Wittig reaction. The final product compositions are affected by a decrease in pressure, due to escape of volatile intermediates, and by replacement of the X- halide ion by the less nucleophilic and basic tosylate ion. Reactions under reflux, in solution in chloroform, or in suspension in benzene, are similar to those of the molten salts, but yields are generally lower at the lower temperatures. Copyright Taylor & Francis Group, LLC.
- Castaneda, Fernando,Aliaga, Christian,Acuna, Cristina,Silva, Paul,Bunton, Clifford A.
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experimental part
p. 1188 - 1208
(2009/04/16)
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- Alcohol-assisted phosphine catalysis: One-step syntheses of dihydropyrones from aldehydes and allenoates
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This paper describes the phosphine-catalyzed annulation of methyl allenoate with various aromatic aldehydes to form 6-aryl-4-methoxy-5,6dihydro-2-pyrones. In this reaction, the addition of an alcohol was necessary to induce dihydropyrone formation, with the optimal agent being methanol. Moreover, the addition of n-butyllithium suppressed the formation of the noncyclized product, leading to the exclusive isolation of the dihydropyrone. This method provides an efficient, one-step route toward disubstituted dihydropyrones from simple, stable starting materials.
- Creech, Gardner S.,Kwon, Ohyun
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p. 429 - 432
(2008/09/19)
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- Rapid and efficient access to meso-2,5-cis-disubstituted pyrrolidines by double aza-Michael reactions of chiral primary amines
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The double aza-Michael reaction of enantiopure primary amines on bis α,β-unsaturated diesters has been studied under various activating conditions. High pressure allowed a rapid and efficient access to meso-2,5-disubstituted pyrrolidines.
- Cabral dos Santos, Leila,Bahlaouan, Zineb,El Kassimi, Khadija,Troufflard, Claire,Hendra, Frederic,Delarue-Cochin, Sandrine,Zahouily, Mohamed,Cave, Christian,Joseph, Delphine
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experimental part
p. 751 - 768
(2009/09/25)
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- Second generation of 5-ethenylbenzofuroxan derivatives as inhibitors of Trypanosoma cruzi growth: Synthesis, biological evaluation, and structure-activity relationships
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In vitro growth inhibitory activity of 21 new 5-ethenylbenzofuroxan derivatives against the protozoan parasite Trypanosoma cruzi, the causative agent of American trypanosomiasis, was studied. The designed compounds possess the previously described exigencies for optimal anti-parasite activity, the 5-ethenylbenzofuroxanyl moiety with different substituents. The synthetic key for preparing the derivatives was the Wittig procedure, that when 5-formylbenzofuroxan was used as the electrophile the corresponding deoxygenated products were marginally generated. Four of the new derivatives displayed remarkable in vitro activities against the epimastigote form of three strains of T. cruzi, Tulahuen 2, CL Brener, and Y. While the three deoxygenated analogues biologically assayed resulted inactives. Unspecific cytotoxicity was evaluated using human macrophages and active derivatives were not toxic at a concentration at least 13 times that of its IC50 against T. cruzi (CL Brener strain). From the preliminary structure-activity relationship studies lipophilicity and electronic requirements were found relevant to anti-T. cruzi activity. Active compounds are more lipophilic than inactive ones and it was also identified that an optimum value of R Swain-Lupton's descriptor is required for optimal activity.
- Porcal, Williams,Hernandez, Paola,Aguirre, Gabriela,Boiani, Lucia,Boiani, Mariana,Merlino, Alicia,Ferreira, Ana,Maio, Rossanna Di,Castro, Ana,Gonzalez, Mercedes,Cerecetto, Hugo
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p. 2768 - 2781
(2008/02/08)
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- Cytotoxic agents and methods of use
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Disclosed are compounds that inhibit proteasomic activity in cells. Also disclosed are pharmaceutical compositions comprising such compounds as well as methods to treat conditions, particularly cell proliferative conditions, such as cancer and inflammator
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Page/Page column 19
(2010/02/14)
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- The syntheses of cyclic spermine alkaloids: Analogues of buchnerine and budmunchiamine C
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The syntheses of two macrocyclic spermine alkaloids, analogues 1 and 2 of budmunchiamine C and buchnerine, in which N,N′-bis(2-aminoethyl)hexane-1,6-diamine (PA 262; 4) replaces spermine as polyamine backbone, were accomplished by two different methods. The first synthetic approach was based on a metal-template intramolecular amidation of tetraamino esters prepared from a Michael addition of protected PA 262 10 to ethyl hexadec-2-ynoate (12) and ethyl prop-2-ynoate 17. respectively (see Schemes 4 and 5. resp.). The consecutive Michael addition of ethane-1,2-diamine to unsaturated esters and aminolysis was employed in the second synthetic approach to prepare the precursors 23 and 24 (Scheme 6). The macrocyclic lactams were then constructed by macrocyclization of sulfonamido derivatives 25 and 26 in DMF with Cs2CO3 as catalyst.
- Li, Yi,Hesse, Manfred
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p. 310 - 323
(2007/10/03)
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- Synthesis and spectroscopic characterization of 1-13C- and 4-13C-plastoquinone-9
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This paper presents the synthesis of 1-13C- and 4-13C-plastoquinone-9 and their characterization with NMR spectroscopy and mass spectrometry. The synthetic scheme has been further adapted to introduce 13C-labeled plastoquinones on all individual and on each combination of positions in the quinone ring. Also a two-step scheme is disclosed to prepare unlabeled plastoquinone-9. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Boers, Rutger B.,Randulfe, Yolanda Pazos,Van Der Haas, Hendrikus N. S.,Van Rossum-Baan, Marleen,Lugtenburg, Johan
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p. 2094 - 2108
(2007/10/03)
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- Specific isotope enrichment of methyl methacrylate
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A synthetic scheme has been developed to prepare methyl methacrylate specifically 13C-labelled at all different positions and in any combination of positions, from simple, commercially available starting materials. According to this scheme methyl (1-13C) and methyl (2-13C)methacrylate (1a and 1b) have been prepared with high label incorporation (99%).
- Werkhoven, Thekla M.,Van Nispen, Reinier,Lugtenburg, Johan
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p. 2909 - 2914
(2007/10/03)
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- Synthesis of α-tocopherol analogues
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A range of α-tocopherol analogues of varying side-chain length and structure has been prepared by the Wittig reaction of alkyltriphenylphosphonium bromides with either 6-benzyloxy-2,5,7,8-tetramethylchroman-2-carbaldehyde (8) or 6-acetoxy-2,5,7,8,-tetramethylchroman-2-carbaldehyde (14). These analogues include 2-hexyl-2,5,7,8-tetramethylchroman-6-ol (11), 2-heptyl-2,5,7,8-tetramethylchroman-6-ol (12) and 2,5,7,8-tetramethyl-2-(pent-l-enyl)chroman-6-ol (15). Methoxycarbonylmethyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (2) was formed by reaction of the triethylammonium salt of trolox (1) with methyl bromoacetate. Reaction of methoxycarbonylmethyltriphenylphosphonium bromide (16) with (8) did not produce the expected methyl 3-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)prop-2-enoate (17), but rather 4-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)but-3-en-2-one (22). A proposed mechanism for this unusual reaction is discussed.
- Suarna, Cacang,Dean, Roger T.,Southwell-Keely, Peter T.
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p. 1129 - 1135
(2007/10/03)
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- REACTION OF WITTIG REAGENTS WITH α,α-DIHALOKETONES. DIBENZOYLMETHANE DIBROMIDE AND 1,3-INDANDIONE DIBROMIDE
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Dibenzoylmethane dibromide (5) and 1,3-indandione dibromide (6) react with ylide-phosphoranes 1a-c to give the α,β-unsaturated esters 10 and 13, respectively.All intermediates are isolated and identified.Structures 10 and 13 as well as the intermediates were confirmed by compatible analytical and spectroscopic results.
- Abdou, Wafaa M.,Ganoub, Neven A. F.
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- Pesticides
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New insecticides are of formula: STR1 wherein R1 represents hydrogen or a methyl group; R2 represents hydrogen or a halogeno or lower alkyl group; R3 represents hydrogen or a halogeno or carbo(lower alkoxy) group which contains at least 2 carbon atoms in the lower alkoxy residue when R2 represents methyl; with the proviso that (a) R2 and R3 each represent hydrogen only when R1 represents methyl, (b) when R1 and R3 each represent hydrogen and R2 represents alkyl, that alkyl group contains at least 2 carbon atoms and (c) when R3 represents halogeno, R2 represents hydrogen or halogeno; and R represents a group which forms insecticidal esters with chrysanthemic acid e.g. 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, α-cyano-3-phenoxybenzyl. The esters are prepared by forming the ester linkage conventionally or by a Wittig reaction using a 3-formyl- or 3-acetyl-2,2-dimethyl cyclopropane carboxylic acid esterified with the desired residue or by an alkyl group which is subsequently converted to the desired residue.
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- Insecticides
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New insecticides are of formula: STR1 wherein R1 represents hydrogen or a methyl group; R2 represents hydrogen or a halogeno or lower alkyl group; R3 represents hydrogen or a halogeno, lower alkyl (which is different to R2 when R2 represents a lower alkyl group) or carbo(loweralkoxy) group which contains at least 2 carbon atoms in the lower alkoxy residue when R2 represents methyl or R2 and R3 together with the carbon atom to which they are attached represent a cycloalkylene ring having at least one endocyclic carbon to carbon double bond; with the proviso that (a) R2 and R3 each represent hydrogen only when R1 represents methyl and (b) R3 contains at least 2 carbon atoms when R1 and R2 each represent hydrogen; and R represents a group which form insecticidal esters with chrysanthemic acid e.g. 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, α-cyano-3-phenoxybenzyl. The esters are prepared by forming the ester linkage conventionally or by a Wittig reaction using a 3-formyl- or 3-acetyl-2,2-dimethyl cyclopropane carboxylic acid esterified with the desired residue or by an alkyl group which is subsequently converted to the desired residue.
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