- Radical-capturing reaction of 5,7,3′,4′-tetramethylquercetin with the AIBN radical initiator
-
In order to clarify the mechanism for the radical-capturing reaction which is initiated at the C3-hydroxyl group of flavonols, 5,7,3′,4′-tetramethylquercetin (TMQ) was reacted with the 2,2′-azobis-isobutyronitrile (AIBN) radical initiator in benzene. Six products, one depside and its two hydrolytic products, one nitrite adduct, and two others, were isolated from the reaction mixture, and their structures were determined by instrumental analyses. The quantitative change to the four main products against the reaction time was measured by an HPLC method. The radical-capturing reaction pathway for TMQ with AIBN is proposed from these products and their quantitative changes. The pathway dividing into two clearly reveals that one subpath formed the depside and its hydrolytic products, while the other formed the nitrite adduct. The reactivity of each two sub-path was nearly the same, different from the case of TMQ and the 2,2′-azobis-2,4-dimethylvaleronitrile (AMVN) radical initiator.
- Ishikawa, Takahiro,Takagi, Michiyo,Kanou, Mamiko,Kawai, Shingo,Ohashi, Hideo
-
-
Read Online
- Synthesis, Antiproliferative and Antioxidant Activity of 3-Mercapto-1,2,4-Triazole Derivatives as Combretastatin A-4 Analogues
-
Two series of 3-mercapto-1,2,4-triazole derivatives containing alkoxy substituents different in size and position were synthesized and their structures were characterized by FT-IR, 1H NMR, 13C NMR spectroscopy and elemental analysis. The synthesized compounds were assessed for their antiproliferative activity against colon cancer cell line (SW480). The results indicated that the size and position of the alkoxy group significantly influenced the antiproliferative activity. The highest cancer cell growth inhibition values were observed for the compounds containing 3,4,5-trimethoxyphenyl groups in their structures (57.74, 54.14 and 60.70% at 50 μM for compounds 5a, 12b and 14, respectively). The synthesized compounds were also subjected to DPPH protocol for evaluating the antioxidant activity. The results showed that all compounds had moderate to high levels of antioxidant capacity as compared to ascorbic acid as standard, the highest free radical scavenging capacity of 75% was observed for compound 4a at 50 μM.
- Al-Mansury, Sadiq,Balakit, Asim A.,Alkazazz, Fatin Fadhel,Ghaleb, Rana A.
-
p. 556 - 565
(2021/09/28)
-
- Synthesis of acyclic and cyclic phosphonates based on substituted 2-hydroxybenzylic alcohols
-
A convenient synthesis of benzylic phosphonates and 2,3-dihydrobenzo[d][1,2]oxaphosphole 2-oxides substituted at the aromatic ring, as well as their precursors, 2-hydroxybenzylic alcohols, from the derivatives of salicylic aldehyde, salicylic acid, and 2-hydroxyacetophenone bearing an additional hydroxy or methoxy group at the para position of the aromatic ring was developed. For the first time, the possibility of selective demethylation of the methoxy group positioned ortho to the methylene phosphonate fragment with retention of the methoxy group at the para position was shown.
- Brel, V. K.,Mikulenkova, E. A.,Mironov, V. F.,Tatarinov, D. A.,Terekhova, N. V.
-
p. 2147 - 2152
(2020/12/09)
-
- Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
-
Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive-Cl,-Br, and free-NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.
- Cao, Ya-Fang,Li, Ling-Jun,Liu, Min,Xu, Hui,Dai, Hui-Xiong
-
p. 4475 - 4481
(2020/04/10)
-
- Phosphite-catalyzed alkoxycarbonylation of aryl diazonium salts
-
In this communication, an interesting phosphite-catalyzed alkoxycarbonylation of aryl diazonium salts has been reported. At room temperature and under CO pressure, moderate to good yields of the desired esters can be produced in the absence of bases or an
- Xu, Jian-Xing,Franke, Robert,Wu, Xiao-Feng
-
supporting information
p. 6180 - 6182
(2018/09/10)
-
- Methylation of Aliphatic and Aromatic Carboxylic Acids with Dimethyl Carbonate under the Influence of Manganese and Iron Carbonyls
-
The synthesis of methyl esters has been carried out via the reaction of aliphatic and aromatic carboxylic acids with dimethyl carbonate in the presence of manganese and iron carbonyls. The optimal ratio of catalyst and reagents and other conditions for the synthesis of methyl esters of carboxylic acids with high yield have been found.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
-
-
- Electrochemical C-H cyanation of electron-rich (Hetero)arenes
-
A straightforward method for the electrochemical C-H cyanation of arenes and heteroarenes that proceeds at room temperature in MeOH, with NaCN as the reagent in a simple, open, undivided electrochemical cell is reported. The platinum electrodes are passivated by ad-sorbed cyanide, which allows conversion of an exceptionally broad range of electron-rich substrates all the way down to dialkyl arenes. The cyanide electrolyte can be replenished with HCN, opening opportunities for salt-free industrial C-H cyanation.
- Hayrapetyan, Davit,Rit, Raja K.,Kratz, Markus,Tschulik, Kristina,Goo?en, Lukas J.
-
supporting information
p. 11288 - 11291
(2018/10/20)
-
- Rational Design of Rod-Like Liquid Crystals Exhibiting Two Nematic Phases
-
Recently, a polar, rod-like liquid-crystalline material was reported to exhibit two distinct nematic mesophases (termed N and NX) separated by a weakly first-order transition. Herein, we present our initial studies into the structure–property relationships that underpin the occurrence of the lower-temperature nematic phase, and report several new materials that exhibit this same transformation. We have prepared material with significantly enhanced temperature ranges, allowing us to perform a detailed study of both the upper- and lower-temperature nematic phases by using small-angle X-ray scattering. We observed a continuous change in d spacing rather than a sharp change at the phase transition, a result consistent with a transition between two nematic phases, structures of which are presumably degenerate.
- Mandle, Richard J.,Cowling, Stephen J.,Goodby, John W.
-
supporting information
p. 14554 - 14562
(2017/10/23)
-
- Microwave-assisted methylation of dihydroxybenzene derivatives with dimethyl carbonate
-
Using a focused microwave reactor, methylation with dimethyl carbonate (DMC) of 1,2- and 1,4-dihydroxybenzene derivatives, found in the product spectrum of lignin depolymerisation, leads to the respective aromatic bis-methyl ethers with excellent isolated yields. Stoichiometric as well as catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are effective for the bis-methylation of these dihydroxybenzenes at relatively mild temperatures (160-190 °C). Conversion of resorcinol (1,3-dihydroxybenzene) under similar conditions leads to a mixture of 1,3-dimethoxybenzene and methyl 2,4-dimethoxybenzoate. The unusual reactivity of resorcinol's phenyl ring towards DMC can be explained by the synergic effect of its two strongly activating ortho/para directing groups.
- Lui, Matthew Y.,Lokare, Kapil S.,Hemming, Ellen,Stanley, Jessica N.G.,Perosa, Alvise,Selva, Maurizio,Masters, Anthony F.,Maschmeyer, Thomas
-
p. 58443 - 58451
(2016/07/06)
-
- Nitrogen enriched mesoporous organic polymer anchored copper(ii) material: An efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems
-
A new copper-grafted mesoporous poly-melamine-formaldehyde (Cu-mPMF) has been synthesized from melamine and paraformaldehyde in DMSO medium, followed by grafting of Cu(ii) at its surface. Cu-mPMF has been characterized by elemental analysis, powder XRD, HR TEM, FE-SEM, N2 adsorption study, FT-IR, UV-vis DRS, TGA-DTA, EPR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The Cu-grafted mesoporous material showed very good catalytic activity in methyl esterification of benzylic alcohols and amidation of nitriles. Moreover, the catalyst is easily recoverable and can be reused seven times without appreciable loss of catalytic activity in the above reactions. The highly dispersed and strongly bound Cu(ii) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-mPMF catalyst. Due to strong binding with the functional groups of the polymer, no evidence of leached copper from the catalyst during the course of reaction emerged, suggesting true heterogeneity in the catalytic process. This journal is
- Molla, Rostam Ali,Iqubal, Md. Asif,Ghosh, Kajari,Kamaluddin,Islam, Sk. Manirul
-
p. 6546 - 6559
(2015/04/14)
-
- Identification of a new series of potent diphenol HSP90 inhibitors by fragment merging and structure-based optimization
-
Heat shock protein 90 (HSP90) is a molecular chaperone to fold and maintain the proper conformation of many signaling proteins, especially some oncogenic proteins and mutated unstable proteins. Inhibition of HSP90 was recognized as an effective approach to simultaneously suppress several aberrant signaling pathways, and therefore it was considered as a novel target for cancer therapy. Here, by integrating several techniques including the fragment-based drug discovery method, fragment merging, computer aided inhibitor optimization, and structure-based drug design, we were able to identify a series of HSP90 inhibitors. Among them, inhibitors 13, 32, 36 and 40 can inhibit HSP90 with IC50 about 20-40 nM, which is at least 200-fold more potent than initial fragments in the protein binding assay. These new HSP90 inhibitors not only explore interactions with an under-studied subpocket, also offer new chemotypes for the development of novel HSP90 inhibitors as anticancer drugs.
- Ren, Jing,Li, Jian,Wang, Yueqin,Chen, Wuyan,Shen, Aijun,Liu, Hongchun,Chen, Danqi,Cao, Danyan,Li, Yanlian,Zhang, Naixia,Xu, Yechun,Geng, Meiyu,He, Jianhua,Xiong, Bing,Shen, Jingkang
-
supporting information
p. 2525 - 2529
(2014/05/20)
-
- Physiological activity of Chinese Lichen (Gyrophora esculenta) component, methyl 2,4-dihydroxy-6-methylbenzoate and the related compounds
-
It was confirmed that there was a higher expression of antioxidant potential in methyl 2,4-dihydroxy-6-methylbenzoate (orsellinic acid methyl ester) (2), which was isolated from methanol extract oil of Chinese lichen Gyrophora esculenta rather than from commercialized ascorbic acid. Taking this into account, 4 types of compounds-(4-7) which are known to be related to compound (2)-have been synthesized by using 2,4-dihydroxy benzoic acid (3) as starting material. After that, some physiological activity tests on these compounds have been conducted in the following aspects: antioxidant potential, cytotoxicity, cytokine suppressant effect and histamine liberation inhibition and the effects have been evaluated, respectively. The result shows that (2) and methyl 2,4-dihydroxybenzoate (4) showed high radical expression in both antioxidant potential and histamine liberation inhibition. It was also found that none of these compounds expresses cytotoxicity.
- Wu, Shuhsien,Zhao, Zhendong,Okada, Yoshiharu,Watanabe, Yoshiyuki,Takahata, Toshiyuki,Inoue, Toshio,Otsubo, Eiji,Wang, Jing,Lu, Yanju,Nomura, Masato
-
p. 702 - 708
(2014/06/09)
-
- NMR methodology for complex mixture 'separation'
-
Mixture 'separation' by NMR is demonstrated through the development of a pseudo 4D NMR experiment, 3D IPAP INEPT-INADEQUATE-HSQC, designed for the structural elucidation of 13C tagged compounds.
- Bell, Nicholle G. A.,Murray, Lorna,Graham, Margaret C.,Uhrin, Dusan
-
supporting information
p. 1694 - 1697
(2014/02/14)
-
- Copper-catalyzed methyl esterification reactions via C-C bond cleavage
-
The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
- Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
-
p. 9898 - 9905
(2013/10/22)
-
- Alkylation of substituted benzoic acids in a continuous flow microfluidic microreactor: Kinetics and linear free energy relationships
-
Alkylation of para-substituted benzoic acids by iodomethane using an organic superbase, 1,8-bis(tetramethylguanidino)naphthalene (TMGN) in DMF was chosen as a model reaction to test the quality of the control of experimental parameters in a continuous flow microfluidic reactor as it is expected to follow a perfect second order kinetics with a large dynamics by varying the substituents. These conditions may be directly used for the synthesis of natural product esters. Because TMGN reacts slowly with iodomethane, the three different mixing strategies between substrate, base and alkylating reagent were compared. The rate constants were determined for the reaction with a set of alkylating agents and in different solvents. In order to test the quality of the obtained data, temperature effect and free energy relationships, which are expected to follow predictable laws, were investigated. The kinetics vary over 6 orders of magnitude and follows a perfect Arrhenius law, allowing the determination of the energies, enthalpies, and entropies of activation. Finally, we established a Hammett linear relationship for a series of 16 substituted benzoic acids, leading to a reaction constant ρ of -0.65 for this reaction. The quality of the obtained kinetics allowed us to discuss the outliers. All kinetics were obtained with less than 0.5 mmol of substrate.
- Gholamipour-Shirazi, Azarmidokht,Rolando, Christian
-
experimental part
p. 811 - 818
(2012/08/07)
-
- Reduction of carboxylic acids using esters of benzotriazole as high-reactivity intermediates
-
Herein, we describe a simple and practical protocol for the reduction of carboxylic acids via the in situ formation of hydroxybenzotriazole esters followed by reaction with sodium borohydride to give the corresponding alcohols. The reaction proceeds with excellent yields in the presence of water. Georg Thieme Verlag Stuttgart - New York.
- Morales-Serna, Jose Antonio,Garcia-Rios, Erendira,Bernal, Jorge,Paleo, Ehecatl,Gavino, Ruben,Cardenas, Jorge
-
scheme or table
p. 1375 - 1382
(2011/06/19)
-
- Ortho-selectivity in SNAr substitutions of 2,4-dihaloaromatic compounds. Reactions with anionic nucleophiles
-
The nucleophilic addition of organic anions to aromatic compounds with halogens positioned both ortho and para to activating groups was studied in a variety of solvents. Substrates showed strong preferences for ortho substitution in most cases. Evidence is presented for activating group-dependent coordination, which contributes to very high ortho-selectivity in nonpolar solvents. This also drives the overall reaction rate in these solvents, and is of close to the same magnitude of rate increase derived from polar solvents. para-Products are maximized by using crown ethers in protic solvents. Solvent effects overall are very different from corresponding reactions with amine nucleophiles due primarily to the different charges present in the transition states, and to solvation of the nucleophile.
- Wendt, Michael D.,Kunzer, Aaron R.
-
scheme or table
p. 3041 - 3044
(2010/07/18)
-
- TRIAZOLE DERIVATIVES II
-
Novel triazole derivatives of the formula (I) in which R1—R6 and Y have the meanings indicated in Claim 1, are HSP90 inhibitors and can be used for the preparation of a medicament for the treatment of diseases in which the inhibition, regulation and/or modulation of HSP90 plays a role.
- -
-
Page/Page column 30
(2010/02/17)
-
- Identification of a potent new chemotype for the selective inhibition of PDE4
-
A series of substituted 3,6-diphenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines were prepared and analyzed as inhibitors of phosphodiesterase 4 (PDE4). Synthesis, structure-activity relationships, and the selectivity of a highly potent analogue against related phosphodiesterase isoforms are presented.
- Skoumbourdis, Amanda P.,Huang, Ruili,Southall, Noel,Leister, William,Guo, Vicky,Cho, Ming-Hsuang,Inglese, James,Nirenberg, Marshall,Austin, Christopher P.,Xia, Menghang,Thomas, Craig J.
-
p. 1297 - 1303
(2008/09/20)
-
- Alternatives to N,N-diethyl-2,4-dimethoxybenzamide as a precursor for the synthesis of 6,8-dimethoxy-3-methyl-3,4-dihydro-1H-isochromen-1-one
-
Although the amide group of N,N-diethyl-2,4-dimethoxybenzamide facilitates directed ortho-metallation and subsequent allylation of the aromatic ring, it is not readily hydrolyzed prior to conversion into the title isochromenone. This article describes the use of 1-(2-allyl-4,5-dimethoxybenzoyl)-4-methylpiperazine and N,N-diethyl-2-(2-hydroxypropyl)-4,6-dimethoxybenzamide as alternative substrates for conversion into 6,8-dimethoxy-3-methyl-3,4-dihydro-1H-isochromen- 1-one. Copyright Taylor & Francis Group, LLC.
- Van Otterlo, Willem A. L.,Michael, Joseph P.,De Koning, Charles B.
-
p. 3611 - 3621
(2008/03/14)
-
- TRIAZOLE DERIVATIVES
-
The invention relates to novel triazole derivatives of formula (I) wherein R1 - R6 and Y have the designations cited in patent claim 1. Said derivatives are HSP90 inhibitors, and can be used to produce a medicament for treating diseases wherefore the inhibition, regulation and/or modulation of HSP90 plays an important role.
- -
-
Page/Page column 84
(2008/06/13)
-
- NOVEL BENSOPHENONE DERIVATIVES OR SALTS THEREOF
-
A benzophenone derivative represented by the following formula: whereinR1 represents, for example, an optionally substituted heterocyclic group, or a substituted phenyl group; Z represents, for example, an alkylene group; R2 represents, for example, a carboxyl group optionally protected with alkyl;R3 represents, for example, an optionally protected hydroxyl group; R4 represents, for example, an optionally substituted cycloalkyloxy group; and R5 represents, for example, a hydrogen atom, ???or a salt thereof has anti-arthritic activity, inhibits bone destruction caused by arthritis, and provides high safety and excellent pharmacokinetics and thus is useful as therapeutic agent for arthritis. These compounds have inhibitory effect on AP-1 activity and are useful as preventive or therapeutic agent for diseases in which excessive expression of AP-1 is involved.
- -
-
-
- Synthesis and modeling studies with monocyclic analogues of mycophenolic acid
-
Two stepwise procedures, developed for the introduction of the (E)-4- methyl-4-hexenoic acid side chain of mycophenolic acid, were used in the synthesis of monocyclic mycophenolic acid analogues 2a-i. The derivatives with a methyl group or hydrogen at C-4 and lacking the lactone moiety were much less cytotoxic than mycophenolic acid. The menocyclic analogues with a C-4 chloro group did show some activity, albeit much less than mycophenolic acid. The observed differences in potency are rationalized by semiempirical calculations of intramolecular H-bonds.
- Anderson, Wayne K.,Boehm, Terri L.,Makara, Gergely M.,Swann, R. Thomas
-
-
- A new derivative of benzoic acid from Pluchea lanceolata
-
From the leaves of Pluchea lanceolata, a new derivative of benzoic acid, pluchoic acid has been isolated and its structure established as 2-methoxy-4-hydroxybenzoic acid by chemical and spectroscopic data.
- Chopra, Neeraj,Alam, M. Sarwar,Ali
-
p. 1352 - 1353
(2007/10/03)
-
- Manganese(III)-Mediated Formylation of Aromatic Compounds in the Presence of Malonic Acid
-
The reaction of naphthlenes with malonic acid in the presence of manganese(III) acetate gives naphthalenecarbaldehydes and naphthalenecarboxylic acids.Similar reactions of anthracene, pyrene, and methoxybenzenes also yield formylated and carboxylated products.It was found that the formyl group introduced to the aromatic ring was not derived from carboxymethyl radical generated directly by the thermolysis of manganese(III) acetate, but from a dicarboxymethyl radical formed by the interaction of malonic acid and manganese(III) acetate.In addition, it was also found that the dicarboxymethyl radicals attacked the position of the highest electron density on the aromatic ring and that this formylation was effective when the ionization potential of the aromatic copound was lower than 7.8 eV.
- Nishino, Hiroshi,Tsunoda, Katsunori,Kurosawa, Kazu
-
p. 545 - 550
(2007/10/02)
-
- Diels-Alder Reactions with 2H-Pyran-2-ones: Reactivity and Selectivity
-
2H-Pyran-2-ones 1 react with maleic anhydride (2) in a double Diels-Alder reaction to give bicyclooct-2-ene-5,6:7,8-tetracarboxylic dianhydrides 5; the syn/syn structure was established.As expected, the reactivity of 1 was increased by electron donor substituents (OR, alkyl) and diminished by electron withdrawing substituents (CO2R).The steric influence of substituents at C-6 also decrease the reactivity of 1. - Methyl propiolate (6) and phenylacetylene (9) react with 1 to form the Diels-Alder products 7 which suffer CO2 elimination to yield methyl benzoates 8 with low and biphenyls 10 with high regioselectivity, respectively.
- Effenberger, Franz,Ziegler, Thomas
-
p. 1339 - 1346
(2007/10/02)
-
- METALATION REACTIONS. VI. STERIC LIMITS IN THE PREPARATION OF 1,2,3-TRI-SUBSTITUTED BENZENE DERIVATIVES
-
Metalation of 1,3-dialkoxy-, 1-alkoxy-3-(alkylthio)- and 1,3-bis-(alkylthio)-benzenes with n-butyllithium has been examined to verify the possibility of preparing 1,2,3-tri-substituted benzene derivatives.The reaction is affected by steric hindrance.The yields of the metalation in the position ortho to both the substituents decrease as steric requirement increases becoming zero when the bulk of both the alkyl substituent and the hetero-atom is increased.It has been shown that synthesis of 1,2,3-tri-substituted derivatives by this route is feasible only with small substituents.
- Cabiddu, Salvatore,Maccioni, Antonio,Piras, Pier Paolo,Plumitallo, Antonio
-
p. 123 - 128
(2007/10/02)
-