- Decarboxylative Generation of 2-Azaallyl Anions: 2-Iminoalcohols via a Decarboxylative Erlenmeyer Reaction
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Condensation between the tetrabutylammonium salt of 2,2-diphenylglycine and aldehydes results in a decarboxylative Erlenmeyer reaction, affording 1,2-diaryl-2-iminoalcohols as a mixture of diastereomers in good yields. The diastereomeric ratio shifts over time, with the anti diastereomer and the syn oxazolidine tautomer serving as the kinetic and thermodynamic products, respectively. Addition of Lewis acids can catalyze the rates of reaction and product equilibration. The results highlight the stereochemical promiscuity of 1,2-diaryl-2-iminoalcohols in the presence of Lewis acids and Bronsted bases. (Chemical Presented).
- Tang, Shaojian,Park, Jong Yeun,Yeagley, Andrew A.,Sabat, Michal,Chruma, Jason J.
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Read Online
- Aggregation-induced emission enhancement in halochalcones
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A family of push-pull fluorophores, consisting of a chalcone core decorated with electron-donating substituents and halogen atoms, was designed and synthesized. Luminescence studies were performed in solution, aggregate form and in the solid state. Although some compounds are only weakly fluorescent in solution, all are emissive in the solid state showing aggregation-induced emission enhancement. In the crystalline state, the halogen atoms are not involved in halogen bonds but their presence strongly influences the aggregation-induced emission properties of the fluorophores.
- Vaz, Patricia A. A. M.,Rocha, Jo?o,Silva, Artur M.S.,Guieu, Samuel
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Read Online
- Electricity Driven 1,3-Oxohydroxylation of Donor-Acceptor Cyclopropanes: a Mild and Straightforward Access to β-Hydroxy Ketones
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An unprecedented external oxidant-free electrochemical protocol for 1, 3-oxohydroxylation of donor-acceptor cyclopropane is disclosed. The strategy encompasses the activation of the labile π-electron cloud of the aryl ring to cleave the strained Csp3?Csp3 bond of cyclopropane to afford the β-hydroxy ketones via insertion of molecular oxygen. More significantly, based on the detailed mechanistic investigations and cyclic voltammetry experiments, a plausible mechanism is proposed.
- Banerjee, Prabal,Maajid Taily, Irshad,Saha, Debarshi
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supporting information
p. 5053 - 5057
(2021/09/30)
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- THERAPY
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The invention addresses radioresistance in cancer treatment involving radiotherapy and, in particular, limitations associated with the use of the drug sulfasalazine. Specifically, it provides a series of compounds for use as radiosensitizers in the treatment of cancers such as glioblastomas which are lethal and inherently resistant to radiotherapy, in one embodiment, the invention provides compounds of general formula (I), their stereoisomers and pharmaceutically acceptable salts for use as radiosensitizers in the treatment of cancer wherein ring A is selected from optionally substituted phenyl, biphenyl and fluorenyl; each X is independently selected from: -C1-6 alkyl (preferably C1-3 alkyl, e.g. -CH3), -O-C1-6 alkyl (preferably -O-C1-3 alkyl, e.g, -OCH3), -S-C1-6 alkyl (preferably -S-C1-3 alkyl, e.g, -SCH3), -OH, -SH, -CO2R1 (where R1 is H or C1-6 alkyl, preferably C1-3 alkyl, e.g. -CH3), -SO2-C1-6 alkyl (preferably -SO2-C1-3 alkyl, e.g. -SO2-CH3), -SO2-NR2R3 (where R2 is H and R3 is optionally substituted phenyl), -NR4R5 (wherein R4 and R5 are independently selected from H, C1-6 alkyl (preferably C1-3 alkyl, e.g. -CH3), and -CO-C1-6 alkyl (preferably -CO-C1-3 alkyl, e.g. -CO-CH3), halogen (e.g. F, Cl or Br), and optionally substituted tetrazolyl; n is an integer from 0 to 5, preferably 0 to 2, e.g. 1 or 2; and denotes an E or Z double bond.
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Page/Page column 25
(2021/04/02)
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- Structure-Activity-Relationship-Aided Design and Synthesis of xCT Antiporter Inhibitors
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The xCT antiporter is a cell membrane protein involved in active counter-transportation of glutamate (outflux) with cystine (influx) over the human cell membrane. This feature makes the xCT antiporter a crucial element of the biosynthesis of the vital free radical scavenger glutathione. The prodrug sulfasalazine, a medication for the treatment of ulcerative colitis, was previously proven to inhibit the xCT antiporter. Starting from sulfasalazine, a molecular scaffold jumping followed by SAR-assisted design and synthesis provided a series of styryl hydroxy-benzoic acid analogues that were biologically tested in vitro for their ability to decrease intracellular glutathione levels using four different cancer cell lines: A172 (glioma), A375 (melanoma), U87 (glioma) and MCF7 (breast carcinoma). Depletion of glutathione levels varied among the compounds as well as among the cell lines. Flow cytometry using propidium iodide and the annexin V marker demonstrated minimal toxicity in normal human astrocytes for a promising candidate molecule (E)-5-(2-([1,1′-biphenyl]-4-yl)vinyl)-2-hydroxybenzoic acid.
- Cirillo, Davide,Sarowar, Shahin,?yvind Enger, Per,Bj?rsvik, Hans-René
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p. 2650 - 2668
(2021/06/01)
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- Linear diarylheptanoids as potential anticancer therapeutics: synthesis, biological evaluation, and structure–activity relationship studies
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In efforts to develop effective anticancer therapeutics with greater selectivity toward cancerous cell and reduced side-effects, such as emetic effects due to detrimental action of the drug toward the intestinal flora, a series of linear diarylheptanoids (LDHs) were designed and synthesized in 7 steps with good-to-moderate yields. All synthesized compounds were evaluated for their antibacterial, antiproliferative, and topoisomerase-I and -IIα inhibitory activity. Overall, all compounds showed little to no activity against the bacterial strains tested. Most of the synthesized compounds showed good antiproliferative activity against human breast cancer cell lines (T47D); specifically, the IC50 values of compounds 6a, 6d, 7j, and 7e were 0.09, 0.64, 0.67, and 0.99 μM, respectively. Among the tested compounds, 7b inhibited topo-I by 9.3% (camptothecin 68.8%), 7e and 7h inhibited topo-IIα by 38.4 and 47.4% (etoposide 76.9%), respectively, at the concentration of 100 μM. These results suggest that a set of promising anticancer agents can be obtained by reducing inhibitory actions on different microbes to provide enhanced selectivity against cancerous cells.
- Motiur Rahman,Lu, Yang,Lee, Hwa-Jong,Jo, Hyunji,Yin, Wencui,Alam, Mohammad Sayed,Cha, Hyochang,Kadi, Adnan A.,Kwon, Youngjoo,Jahng, Yurngdong
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- Dehydroxymethyl Bromination of Alkoxybenzyl Alcohols by Using a Hypervalent Iodine Reagent and Lithium Bromide
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We describe the dehydroxymethylbromination of alkoxybenzyl alcohol by using a hypervalent iodine reagent and lithium bromide in F 3 CCH 2 OH at room temperature. Selective monobromination or dibromination was possible by adjusting the molar ratios of hypervalent iodine reagent and lithium bromide.
- Shibata, Ayako,Kitamoto, Sara,Fujimura, Kazuma,Hirose, Yuuka,Hamamoto, Hiromi,Nakamura, Akira,Miki, Yasuyoshi,Maegawa, Tomohiro
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supporting information
p. 2275 - 2278
(2018/10/20)
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- Novel synthetic process of isovanillin
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The invention discloses a novel synthetic process of isovanillin, and relates to the field of organic synthesis technology. The method comprises: reacting 4-hydroxybenzaldehyde as a raw material with bromine to obtain 3-bromo 4-hydroxybenzaldehyde, reacting with methyl iodide to obtain 3-bromo-4-methoxy benzaldehyde, and then performing hydrolysis to obtain the isovanillin under the action of sodium hydroxide and cuprous chloride. The method adopts cheap and easily obtained 4-hydroxybenzaldehyde as the starting material, the isovanillin is obtained under mild reaction conditions, and the economic efficiency of a process is improved while the cost is reduced. The total yield of the product, isovanillin, obtained by using the optimum process is up to 64.1%, the conversion rates of the raw materials in each step are significantly increased, and the method is suitable for industrial production.
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Paragraph 0015; 0031; 0035; 0039; 0043; 0047
(2017/09/18)
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- Conversion of thiols into sulfonyl halogenides under aerobic and metal-free conditions
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An environmentally benign, metal-free synthesis of sulfonyl chlorides and bromides from thiols in the presence of ammonium nitrate, an aqueous solution of HCl and HBr and oxygen as a terminal oxidant was developed. The reactivity of various substituted thiophenols, benzylic-, aliphatic- and heteroaromatic thiols was examined. Ammonium nitrate served as a source of nitrogen oxides (NO/NO2), which are the crucial players in a redox-catalytic cycle. Sulfonyl chlorides and bromides were isolated without extraction and "filtered" over a short pad of silica gel; the use of solvents was greatly reduced in comparison with traditional isolation and purification. A "one-pot" protocol for the conversion of thiol into sulfonamide is also demonstrated. Scale-up experiments on the preparation of sulfonyl chloride and bromide are shown. A possible reaction pathway is discussed.
- Jereb, Marjan,Hribernik, Luka
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supporting information
p. 2286 - 2295
(2017/07/24)
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- Mechanistic study on iodine-catalyzed aromatic bromination of aryl ethers by N-Bromosuccinimide
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Although iodine-catalyzed reaction has rapid advances in recent years, examples on iodine-catalyzed bromination are rare and the mechanism of these reactions remains unclear. Herein, we reported an I2-catalyzed aromatic bromination of aryl ethers by NBS and presented the details of the mechanistic study including kinetic study and the study of kinetic isotope effects. The study revealed that the reaction was actually catalyzed by IBr formed in the induction period, and the rate-determining step was the HBr-elimination of the Wheland intermediate assisted by IBr.
- Pramanick, Pranab Kumar,Hou, Zhen-Lin,Yao, Bo
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p. 7105 - 7114
(2017/11/27)
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- Regioselective monobromination of aromatics via a halogen bond acceptor-donor interaction of catalytic thioamide and N-bromosuccinimide
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Regioselective monobromination of various aromatics was achieved at room temperature using N-bromosuccinimide and 5 mol% of thioamides in acetonitrile. With thiourea as catalyst, activated aromatics, such as anisole, acetanilide, benzamide and phenol analogues containing electron donating or withdrawing groups, were brominated with high regioselectivity. Room temperature brominations of weakly activated aromatics and deactivated 9-fluorenone were accomplished by 5 mol% thioacetamide, higher substrates concentrations and longer reaction times. A backbonding of the bromine lone pairs with the π*of C[dbnd]S group and a halogen bond between the halogen bond donor bromine and the halogen bond acceptor sulfur of the thioamide are thought to be the principal interactions and cause of N-bromosuccinimide activation.
- Bovonsombat, Pakorn,Teecomegaet, Pattaradra,Kulvaranon, Panisanun,Pandey, Aditi,Chobtumskul, Kittithorn,Tungsirisurp, Sireethorn,Sophanpanichkul, Punyanuch,Losuwanakul, Satreerat,Soimaneewan, Dechathon,Kanjanwongpaisan, Patcharida,Siricharoensang, Pornpawit,Choosakoonkriang, Sirirat
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p. 6564 - 6572
(2017/10/17)
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- Synthesis and evaluation of 1-hydroxy/methoxy-4-methyl-2-phenyl-1 H-imidazole-5-carboxylic acid derivatives as non-purine xanthine oxidase inhibitors
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Xanthine oxidase is a key enzyme that catalyses hypoxanthine and xanthine to uric acid, whose overproduction leads to the gout-causing hyperuricemia. In this study, a series of 1-hydroxy/methoxy-4-methyl-2-phenyl-1H-imidazole-5-carboxylic acid derivatives (4ae4k and 6ae6k) was synthesized and evaluated for their inhibitory potency against xanthine oxidase. The 1-hydroxyl substituted derivatives 4ae4k showed excellent inhibitory potency with IC50 values ranging from 0.003 μM to 1.2 μM, with compounds 4d (IC50= 0.003 μM), 4e (IC50 = 0.003 μM), and 4f (IC50 = 0.006 μM) manifesting the most potent xanthine oxidase inhibitory potency that were comparable with that of Febuxostat (IC50 = 0.01 μM). LineweavereBurk plot analysis revealed that representative compound 4f acted as a mixed-type inhibitor for xanthine oxidase. The basis of significant inhibition of xanthine oxidase by 4f was rationalized by its molecular docking into the active site of xanthine dehydrogenase.
- Chen, Shaolei,Zhang, Tingjian,Wang, Jian,Wang, Fangyang,Niu, Handong,Wu, Chunfu,Wang, Shaojie
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p. 343 - 353
(2015/09/22)
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- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
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We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
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supporting information
p. 2154 - 2156
(2015/03/18)
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- Concise total synthesis of aplysinellamides A and B
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Concise and efficient total syntheses of bromotyrosine-derived metabolites aplysinellamides A and B, isolated from Australian marine sponge Aplysinella sp., have been accomplished in seven steps. A condensation between cinnamic acid and Boc-D-lysine methyl ester was applied to form the amide skeleton as a key step.
- Gan, Haifeng,Huang, Yu,Feng, Weiyang,Zhu, Wentong,Guo, Kai
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p. 336 - 339
(2015/08/11)
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- Selective and efficient oxidation of benzylic alcohols to benzaldehydes and methyl benzoates by dibromo-5,5-dimethylhydantoin
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A selective and efficient method of oxidizing benzyl alcohols to benzaldehydes and methyl benzoates by using 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) as oxidant is developed. One-step conversion of benzyl alcohols to methyl benzoates in methanol at room temperature for 12 hours is achieved without any catalysts. Moreover, para-substituted benzyl alcohols are obtained in 86-98% yield. When dichloromethane is used as solvent, further oxidation of benzaldehydes to esters is well controlled, selectively affording benzaldehydes in 89-99% yield within 30 minutes.
- Li, Zhongzhou,Zhu, Wei,Bao, Jinlong,Zou, Xinzhuo
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supporting information
p. 1155 - 1164
(2014/04/03)
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- Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
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We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
- Bose, Anima,Mal, Prasenjit
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supporting information
p. 2154 - 2156
(2014/04/03)
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- Bromination of arenes using I2O5-KBr in water
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An efficient and environmentally benign bromination of various aromatic compounds using aN aqueous I2O5-KBr system at room temperature has been developed in this work. A series of aromatic compounds such as acetophenones, benzaldehydes, benzoic acids, anilines, amides, and aminopyridine have been successfully brominated in excellent regioselectivities and good yields under the typical reaction conditions. The features of KBr as brominating reagent, water as solvent, and mild conditions make this system an attractive synthetic procedure. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Hou, Jieping,Li, Zejiang,Jia, Xiao-Dong,Liu, Zhong-Quan
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supporting information
p. 181 - 187
(2013/12/04)
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- SPIRO-SUBSTITUTED OXINDOLE DERIVATIVES HAVING AMPK ACTIVITY
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The present invention relates to compounds of formula (I), which have valuable pharmacological properties, in particular are activators of AMPK and which are therefore useful in the treatment of certain disorders that can be prevented or treated by activation of this receptor. The compounds are suitable for treatment and prevention of diseases which can be influenced by this receptor, such as metabolic diseases, in particular diabetes type 2.
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Page/Page column 82
(2015/01/07)
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- OLEFIN SUBSTITUTED OXINDOLES HAVING AMPK ACTIVITY
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The present invention relates to compounds of formula (I), which have valuable pharmacological properties, in particular are activators of AMPK and which are therefore useful in the treatment of certain disorders that can be prevented or treated by activation of this receptor. The compounds are suitable for treatment and prevention of diseases which can be influenced by this receptor, such as metabolic diseases, in particular diabetes type 2.
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Page/Page column 69
(2015/01/07)
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- Phosphonium salts and aldehydes from the convenient, anhydrous reaction of aryl acetals and triphenylphosphine hydrobromide
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The reactions of aryl acetals/ketals and triphenylphosphine hydrobromide gave the corresponding aldehydes/ketones and alkyl phosphonium bromides. This reaction was applied to convert acetals/ketals to the corresponding aldehydes/ketones under an anhydrous
- Ramanathan, Mani,Hou, Duen-Ren
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- Total synthesis of acerogenins E, G and K, and centrolobol
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The first total synthesis of the diarylheptanoid acerogenins E and K, isolated from Acer nikoense MAXIM., is described. Formation of the 13-membered m,m-cyclophane skeleton was successfully achieved on the basis of a domino process involving a Miyaura arylborylation-intramolecular Suzuki reaction. The cyclization precursor was prepared via a Wittig reaction and Claisen-Schmidt condensation, which proceeded in moderate yields. The total synthesis of acerogenin G and centrolobol was also achieved from a common synthetic intermediate.
- Ogura, Tetsuhiro,Usuki, Toyonobu
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p. 2807 - 2815
(2013/03/28)
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- A facile and convenient synthesis of new substituted heteroarylchalcones and flavones by microwave irradiated suzuki-miyaura cross coupling reaction in aqueous medium
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Chalcones 6a-g and corresponding flavones 7a-g having various heteroaryl substituents have been synthesized. The starting compound 5-formyl-2- methoxyboronic acid 3 was prepared by a series of reactions; Bromination of 4-methoxybenzaldehyde (4-CH3O-C8H4-CHO) with catalyst, anhyd AICI3 in DCE (1,2-dichloroethane) gave 3-bromo-4-methoxybenzaldehyde 1. The aldehydic group from 3-bromo-4- methoxybenzaldehyde 1 was protected by acetalization with 1,3-propane-diol and ethyl orthoformate with phase transfer catalyst tetrabutylammonium tribromide (TBATB) producing the corresponding 2-(3-bromo-4-methoxyphenyl)-1,3-dioxan 2 which on treatment with trimethyl borate [(MeO)3B] in presence of n-butyllithium at 70° gave 5-formyl-2-methoxyboronic acid 3. Suzuki-Miyaura coupling of 3 with different heteroaryl bromides 4a-g in presence of [(C 6H5)3P]4Pd (0) catalyst, aq.Na 2CO3 (2N) as base and aq DMF (N,N-dimethylformamide) as solvent and micro-wave irradiation for 1 to 2.5 min. in a Panasonic microwave set at 1000 Watts and 80% microwave power, yielded 3-heteroaryl-4- methoxybenzaldehydes 5a-g. Claisen-Schmidt condensation of 5a-g with 2-hydroxyacetophenone in presence of ethanolic KOH produced 3-heteroaryl- 2′-hydroxy-4-methoxychalcones 6a-g. On cyclizing with a mixture of l 2 and DMSO, chalcones 6a-g gave 3'-heteroaryl-4′- methoxyflavones 7a-g.
- Joshi, Vidya,Hatim, Jaywant Govind
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p. 281 - 288
(2013/09/24)
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- Design, synthesis and biological evaluation of novel 4-hydroxybenzene acrylic acid derivatives
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A series of 4-hydroxybenzene acrylic acid derivatives were designed and synthesized based on the ferulic acid of natural active ingredients. The tested compound 5a, 5f and 6a have significant anti-inflammatory activity with suppression rates of 45.29%, 44.75% and 24.11%, respectively, compared with that of indomethacin, and their cardiac toxicity was not observed. The structure-function relationship shows that the p-hydroxyl group on the α-position benzene ring, particularly if acetylated, contributes to the considerable anti-inflammatory activity; that the carboxyl group on the double bond, if esterified, also contributes to the anti-inflammatory activity; that the p-methylsulfonyl group on the other benzene ring, whose introduction is due to the COX-2 selectivity, also contributes to anti-inflammatory activity surprisingly.
- Mao, Jin-Long,Ran, Xiang-Kai,Tian, Jing-Zhen,Jiao, Bo,Zhou, Hong-Lei,Chen, Li,Wang, Zhen-Guo
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scheme or table
p. 1549 - 1553
(2011/04/22)
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- Aromatic bromination of aldehydes and ketones using 1,3-di-n- butylimidazolium
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An environmentally benign and efficient process for the preparation of monobromo derivatives of aryl aldehydes and ketones was developed by simple and practical reactions of aryl aldehydes or ketones with 1,3-di-n-butylimidazolium tribromide ([BBIm]Br3), as a brominating reagent under solvent-free conditions in very high yields. The process has several advantages: high conversions, short reaction time, mild reaction conditions, simple workup with good to quantitative yields and re-usable ionic liquid.
- Borikar,Daniel
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experimental part
p. 531 - 536
(2012/07/01)
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- Total synthesis, antiprotozoal and cytotoxicity activities of rhuschalcone VI and analogs
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The total synthesis of a potent antiplasmodial natural bichalcone, rhuschalcone VI, is described starting from simple and available resorcinol and 4-hydroxybenzaldehyde. Key steps include the solvent-free Aldol syntheses of chalcones, and the successful application of the Suzuki-Miyaura coupling reaction in the synthesis of bichalcones. The present work constitutes a general method for the rapid syntheses of a number of bichalcones related to rhuschalcone VI. Some of the bichalcones showed moderate antiprotozoal activities against Bodo caudatus, a preliminary screening system for antitrypanosomal activities, most of them with little or no cytotoxicity.
- Mihigo, Shetonde O.,Mammo, Wendimagegn,Bezabih, Merhatibeb,Andrae-Marobela, Kerstin,Abegaz, Berhanu M.
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experimental part
p. 2464 - 2473
(2010/07/02)
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- The first total synthesis of aplysamine 6, an inhibitor of isoprenylcysteine carboxy methyltransferase
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The first total synthesis of aplysamine 6, an inhibitor of isoprenylcysteine carboxy methyltransferase (Icmt), was accomplished in an overall high yielding reaction sequence.
- Ullah, Nisar,Arafeh, Khaled M.
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scheme or table
p. 158 - 160
(2009/04/14)
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- A novel simple and efficient bromination protocol for activated arenes
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An efficient, high yielding, and environmentally benign bromination using an alkali metal bromide as the bromine source is disclosed. Investigation of the protocol revealed that the method operates for activated arenes producing the corresponding monobrominated products in good to excellent yields.
- Tsoukala, Anna,Liguori, Lucia,Occhipinti, Giovanni,Bj?rsvik, Hans-Rene?
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supporting information; experimental part
p. 831 - 833
(2009/05/07)
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- Direct oxidation of N-benzylamides to aldehydes or ketones by N-bromosuccinimide
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A simple and efficient approach for the one-pot transformation of N-benzylamides to aldehydes or ketones under mild conditions was reported. All the 20 substrates gave moderate to excellent oxidative yields under the optimized conditions. Our study may provide a new approach for the one-pot synthesis of aldehydes or ketones from the corresponding amides. Copyright Taylor & Francis Group, LLC.
- Wang, Guangjun,Li, Zhengwei,Ha, Chengyong,Ding, Ke
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p. 1629 - 1637
(2008/09/21)
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- A mild and efficient method for the oxidation of benzylic alcohols by two-phase electrolysis
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Electrochemical oxidation of benzylic and substituted benzylic alcohols by two-phase electrolysis yields the corresponding aldehydes as products. The reaction was carried out in a single compartment cell with platinum electrodes at room temperature in chloroform using an aqueous sodium bromide solution (25%) containing a catalytic amount of HBr. The two-phase electrolysis resulted in high yields (74-96%) of benzaldehyde from primary alcohols and secondary alcohols were oxidized to the corresponding ketone but only in low yields under these conditions.
- Raju, Thasan,Manivasagan, Sankar,Revathy, Balachandran,Kulangiappar, Kumarasamy,Muthukumaran, Arunachalam
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p. 3681 - 3684
(2008/02/03)
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- Syntheses and radical scavenging activities of resveratrol derivatives
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Nine new resveratrol derivatives, having bromo, iodo, and fluoroethyl groups, were designed and synthesized. All compounds having free phenol groups showed good free radical scavenging activity. Among them, 2-bromoresveratrol 19 has a similar free radical scavenging activity to (+)-catechin.
- Lee, Hyun Jung,Seo, Jai Woong,Lee, Bong Ho,Chung, Kyoo-Hyun,Chi, Dae Yoon
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p. 463 - 466
(2007/10/03)
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- A highly efficient procedure for regeneration of carbonyl groups from their corresponding oxathioacetals and dithioacetals using sodium nitrite and acetyl chloride in dichloromethane
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A wide variety of oxathioacetals 1 as well as dithioacetals 2 can be chemoselectively deprotected to the corresponding carbonyl compounds 3 in good yields by employing NaNO2-AcCl and H2O in CH2Cl2 at 0°C to room temperature. Some of the major advantages of this procedure are: mild conditions, easy to handle, highly chemoselective and efficient, high yields and inexpensive reagents. In addition, no acetylation occurs at the hydroxyl group nor chlorination takes place at the double bond.
- Khan, Abu T.,Mondal, Ejabul,Sahu, Priti R.
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p. 377 - 381
(2007/10/03)
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- Bicyclic aromatic compounds and pharmaceutical/cosmetic compositions comprised thereof
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Novel pharmaceutically/cosmetically-active bicyclic aromatic compounds have the structural formula (I): in which Ar1 is a radical having one of the structural formulae (a)-(c): Ar2 is a radical having one of the following formulae (d)-(h): and X is a radical having one of the following formulae (i)-(l): and are useful for the treatment of a wide variety of disease states, whether human or veterinary, for example dermatological, rheumatic, respiratory, cardiovascular and ophthalmological disorders, as well as for the treatment of mammalian skin and hair conditions/disorders.
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Page/Page column 22
(2010/01/31)
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- Bromodecarbonylation and bromodecarboxylation of electron-rich benzaldehydes and benzoic acids with oxone and sodium bromide
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Benzaldehydes and benzoic acids bearing ortho- and paraelectron donating substituents having unshared electron-pair have undergone bromodecarbonylation or bromodecarboxylation on treatment with sodium bromide in the presence of Oxone in aqueous methanol.
- Koo, Bon-Suk,Kim, Eun-Hoo,Lee, Kee-Jung
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p. 2275 - 2286
(2007/10/03)
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- SYNTHESES BASED ON β-PHENYLETHYLAMINES. VI. SYNTHESIS AND MASS-SPECTROMETRIC PROPERTIES OF BIS-β-PHENYLETHYLBENZYLAMINES AND THE PRODUCTS OF THEIR METHYLATION
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Fourteen previously undescribed bases of the bis-β-phenylethylbenzylamine series with a central diphenyl ether group differing by the relative positions of the oxygen bridge and the β-phenylethylbenzylamine substituent have been synthesized.The main directions of the fragmentation of these compounds under electron impact are competing or successive processes of cleavage of the benzyl bonds, accompanied by the structure-dependent transfer of hydrogen atoms.
- Baratov, N. U.,Mil'grom, E. G.,Vinogradova, V. I.,Rashkes, Ya. V.,Yunusov, M. S.
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p. 748 - 759
(2007/10/02)
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- REAGENTS ABD SYNTHETIC METHODS-40 HALOSILANES/CHROMIUM TRIOXIDE AS EFFICIENT OXIDIZING REAGENTS
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Synthetic utility of halosilanes-chromium trioxide reagents as excellent new oxidizing agents is described.They are highly efficient for the oxidation of alcohols to carbonyl compounds, for the oxidative coupling of mercaptans intodisulfides and for a mild cleavage of oximes to carbonyl compounds.Chlorotrimethylsilane-chromium trioxide has been shown to be an efficient oxidizing agent for the conversion of arylmethanes to benzaldehydes.The reagent is applied to the oxidative cleavage of some benzyl esters.A mild procedure for the iodination of organic compounds by means of in situ generated iodonium species from this reagent and molecular iodine is also described.
- Aizpurua, J. M.,Juaristi, M.,Lecea, B.,Palomo, C.
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p. 2903 - 2912
(2007/10/02)
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- Solvolytic Elimination and Hydrolysis promoted by an Aromatic Hydroxy-group. Part 2. The Hydrolysis of 2-Bromo-4-dibromomethylphenol in 95percent 1,4-Dioxane
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The reaction of 2-bromo-4-dibromomethylphenol with water in slightly aqueous (95percent) 1,4-dioxane has been examined kinetically by using u.v. spectroscopy, which provides evidence for the transient formation of the quinone methide, 2-bromo-4-bromomethylenecyclohexa-2,5-dienone, during the hydrolysis.The final product is 3-bromo-4-hydroxybenzaldehyde.The rate of disappearance of starting material is independent of acidity, but is reduced by added or developing bromide ion.The rate of the loss of bromide ion from the phenol is very much greater than that of the corresponding reaction of 2-bromo-4-dibromomethylanisole under the same conditions.An estimate of the value of ?p-OH+ (-1.36), made by using these relative rates, is larger than the value (-0.92) based on relative rates of aromatic electrophilic substitution.Solvent kinetic isotope effects on these reactions are reported; the theoretical implications of variation in the substituent parameter for the hydroxy-group is discussed in terms of solvent effects on H-O hyperconjugation.
- Mare, Peter B. D. de la,Newman, Paul A.
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p. 1797 - 1802
(2007/10/02)
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- ENHANCEMENT OF THE CONJUGATIVE ELECTRON-RELEASING POWER OF THE HYDROXY-GROUP SHOWN BY THE KINETICS OF SOLVOLYSIS OF 2-BROMO-4-DIBROMOMETHYLPHENOL AND OF 2-BROMO-4-DIBROMOMETHYLANISOLE
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The relative rates and kinetic forms for the solvolyses of 2-bromo-4-dibromomethylphenol and its methyl ether lead to a new estimate (?+=-1.6) of the electron-releasing power of the hydroxy-group.
- Mare, Peter B. D. de la,Newman, Paul A.
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p. 1305 - 1308
(2007/10/02)
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