- The [2+2] photocycloaddition of uracil derivatives with ethylene as a general route to cis-cyclobutane β-amino acids
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A three-step procedure, based on the [2+2]-photochemical reaction of uracils with ethylene followed by controlled degradation of the heterocyclic ring, has been developed for the synthesis of a range of C1 - and C2-substituted cis-cyclobutane β-amino acids, in good overall yield. Georg Thieme Verlag Stuttgart.
- Gauzy, Christine,Saby, Bertrand,Pereira, Elisabeth,Faure, Sophie,Aitken, David J.
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Read Online
- Ultrasound-promoted Friedel-Crafts acylation of arenes and cyclic anhydrides catalyzed by ionic liquid of [bmim]Br/AlCl3
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A simple and efficient method of Friedel-Crafts acylation of arenes with succinic anhydride, phthalic anhydride and glutaric anhydride under the action of 1-butyl-3-ethylimidazolium ([bmim]Br/AlCl3 ([bmim]+) cation (ionic liquid) and ultrasound irradiation is presented. Thy purity of products was tested by GC-MS and their structures evaluated by IR and 1H NMR spectroscopy.
- Fekri, Leila Zare,Nikpassand, Mohammad
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Read Online
- A general and versatile synthesis of 4- and 5-oxoacids
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The condensation of Grignard reagents with succinic or glutaric anhydrides in presence of a catalytic amount of CuI is a good way for the preparation of 4- or 5-oxoacids.
- Lhommet,Freville,Thuy,Petit,Celerier
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Read Online
- Three-component, one-pot synthesis of benzo[6,7]cyclohepta[1,2-b]pyridine derivatives under catalyst free conditions and evaluation of their anti-inflammatory activity
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An efficient three-component protocol is described for the synthesis of benzo[6,7]cyclohepta[1,2-b]pyridine derivatives using β-chloroacroleins, 1,3-dicarbonyls and ammonium acetate under catalyst free conditions by using ethanol as reaction media. The mild reaction conditions, operational simplicity and high yields are the advantages of this protocol and the broad scope of this one-pot reaction makes this procedure promising for practical usages. All the final compounds were screened for anti-inflammatory activity. Among the compounds tested, the compounds 5a, 5b, 5c, 5d, 5f, and 5k exhibited significant inhibition of IL-1β and MCP-1 secretion as a measure of anti-inflammatory activity.
- Sajja, Yasodakrishna,Vulupala, Hanmanth Reddy,Bantu, Rajashaker,Nagarapu, Lingaiah,Vasamsetti, Sathish Babu,Kotamraju, Srigiridhar,Nanubolu, Jagadeesh Babu
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Read Online
- Design, synthesis and in vitro anti-tuberculosis activity of benzo[6,7]cyclohepta[1,2-b]pyridine-1,2,3-triazole derivatives
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A series of novel benzo[6,7]cyclohepta[1,2-b]pyridine-1,2,3-triazole hybrids (7a–j & 8a–j) have been designed and synthesized in excellent yields by Huisgen's [3+2] cyclo addition reaction of 3-(azidomethyl)-2-methyl-6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-b]pyridine (5) with various alkynes 6 in presence of copper sulphate and sodium ascorbate and their structures were confirmed by IR, 1H NMR, 13C NMR and HRMS. The newly synthesized compounds 7a–j & 8a–j were evaluated for their in vitro anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv (ATCC 27294). Among the compounds tested, the compounds 7i and 8g displayed most potent activity with MIC value of 1.56 μg/mL with low cytotoxicity.
- Sajja, Yasodakrishna,Vanguru, Sowmya,Vulupala, Hanmanth Reddy,Bantu, Rajashaker,Yogeswari, Perumal,Sriram, Dharmarajan,Nagarapu, Lingaiah
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Read Online
- Visible Light-Driven, Copper-Catalyzed Aerobic Oxidative Cleavage of Cycloalkanones
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A visible light-driven, copper-catalyzed aerobic oxidative cleavage of cycloalkanones has been presented. A variety of cycloalkanones with varying ring sizes and various α-substituents reacted well to give the distal keto acids or dicarboxylic acids with moderate to good yields.
- Xin, Hong,Duan, Xin-Hua,Yang, Mingyu,Zhang, Yiwen,Guo, Li-Na
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p. 8263 - 8273
(2021/06/30)
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- Nitroxyl Catalysts for Six-Membered Ring Bromolactonization and Intermolecular Bromoesterification of Alkenes with Carboxylic Acids
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We developed a nitroxyl-catalyzed bromoesterification of alkenes with bromo reagents, which includes a six-membered ring bromolactonization of alkenyl carboxylic acids catalyzed by AZADO as the nitroxyl radical catalyst, and an intermolecular bromoesterification of alkenes with carboxylic acids using NMO as the N-oxide catalyst. We also accomplished a remote diastereoselective bromohydroxylation via an AZADO-catalyzed six-membered ring bromolactonization and a subsequent ring cleavage reaction with alkylamines to furnish ?-bromo-δ-hydroxy amides with high diastereoselectivity.
- Moriyama, Katsuhiko,Kuramochi, Masako,Tsuzuki, Seiji,Fujii, Kozo,Morita, Takeshi
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supporting information
p. 268 - 273
(2021/01/09)
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- Iridium-Catalyzed Asymmetric Hydrogenation of ?- A nd ?-Ketoacids for Enantioselective Synthesis of ?- A nd ?-Lactones
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A highly efficient asymmetric hydrogenation of ?- A nd ?-ketoacids was developed by using a chiral spiro iridium catalyst (S)-1a, affording the optically active ?- A nd ?-hydroxy acids/lactones in high yields with excellent enantioselectivities (up to >99% ee) and turnover numbers (TON up to 100000). This protocol provides an efficient and practical method for enantioselective synthesis of Ezetimibe.
- Hua, Yun-Yu,Bin, Huai-Yu,Wei, Tao,Cheng, Hou-An,Lin, Zu-Peng,Fu, Xing-Feng,Li, Yuan-Qiang,Xie, Jian-Hua,Yan, Pu-Cha,Zhou, Qi-Lin
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supporting information
p. 818 - 822
(2020/02/15)
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- Asymmetric hydrogenation reaction γ - or δ - ketonato compound (by machine translation)
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The invention relates to the field, of organic chemistry, specifically γ - or δ - keto acid compound asymmetric hydrogenation reaction, reaction formula as follows : Wherein R is H,C. 1 - C6 An alkyl or halogen, is R 1 - 5 in number of substituents . wherein n is 1 or 2;Cat. is a chiral spiro pyrimidyl phosphine ligand iridium complex . and γ - or δ - keto acid compound is subjected to an internal esterification reaction to further prepare a lactone compound. (by machine translation)
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Paragraph 0048-0050
(2020/03/06)
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- Design, synthesis, and evaluation of compounds capable of reducing Pseudomonas aeruginosa virulence
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Anti-virulence approaches in the treatment of Pseudomonas aeruginosa (PA)-induced infections have shown clinical potential in multiple in vitro and in vivo studies. However, development of these compounds is limited by several factors, including the lack of molecules capable of penetrating the membrane of gram-negative organisms. Here, we report the identification of novel structurally diverse compounds that inhibit PqsR and LasR-based signaling and diminish virulence factor production and biofilm growth in two clinically relevant strains of P. aeruginosa. It is the first report where potential anti-virulent agents were evaluated for inhibition of several virulence factors of PA. Finally, co-treatment with these inhibitors significantly reduced the production of virulence factors induced by the presence of sub-inhibitory levels of ciprofloxacin. Further, we have analyzed the drug-likeness profile of designed compounds using quantitative estimates of drug-likeness (QED) and confirmed their potential as hit molecules for further development.
- Hossain, Mohammad Anwar,Sattenapally, Narsimha,Parikh, Hardik I.,Li, Wei,Rumbaugh, Kendra P.,German, Nadezhda A.
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supporting information
(2019/11/26)
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- Photoinduced C—C Bond Cleavage and Oxidation of Cycloketoxime Esters
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A novel structural reorganization of cycloketoxime esters beyond the traditional Beckmann rearrangement process has been established to build cyano-containing ketones in the presence of photocatalyst. This novel transformation is remarkable with selective C—C bond cleavage and an oxidation process enabled by DMSO used as the solvent, oxidant, and oxygen source avoiding acid, base and toxic cyanide salts as the cyano source. Further applications in late-stage modification of complex and chiral molecules have also been reported.
- Zhao, Binlin,Tan, Hui,Chen, Cheng,Jiao, Ning,Shi, Zhuangzhi
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p. 995 - 999
(2018/09/25)
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- Chromatography-free stereoselective synthesis of (R)-3-benzylpiperidine
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The present study describes aza-Michael addition reactions of 4-aroylpent-4-enoic acids with (R)-phenylglycinol. Subsequent spontaneous lactamization yielded the corresponding piperidin-2-ones, which can selectively crystallize in very high diastereomeric purity. These are useful intermediates in the stereoselective syntheses of diverse 3-benzylpiperidines, as herein demonstrated by a chromatography-free and straightforward Gram-scale synthesis of (R)-3-benzylpiperidine hydrochloride.
- Sivák, Ivan,Berke?, Du?an,Ko?í?ek, Jozef,Kolarovi?, Andrej
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supporting information
p. 1079 - 1082
(2018/03/26)
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- Cobalt-catalyzed oxidative cyclization of gem-disubstituted conjugated alkenols
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Aryl gem-disubstituted conjugated alkenols underwent oxidative cyclization affording 2,5,5-trisubstituted tetrahydrofurans in reasonable yields and good diastereoselectivities using the reductive termination variation of the Mukaiyama aerobic oxidative reaction. Under oxidative termination, the same alkenols produced diols and ketonic by-products via the double hydration and beta-scission competing pathways. Furthermore, the differences in alkenol reactivity under the reductive and oxidative termination conditions were investigated.
- Alves, Tania M.F.,Costa, Mateus O.,Bispo, Beatriz A.D.,Pedrosa, Fabiana L.,Ferreira, Marco A.B.
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supporting information
p. 3334 - 3338
(2016/07/11)
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- Highly enantioselective [3+2] coupling of cyclic enamides with quinone monoimines promoted by a chiral phosphoric acid
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Enantioselective [3+2] coupling of cyclic enamides with quinone monoimines was realised using a chiral phosphoric acid as a catalyst. This transformation allowed for the synthesis of highly enantioenriched polycyclic 2,3-dihydrobenzofurans (up to 99.9% ee). The absolute configuration of one product was determined by an X-ray crystal structural analysis. We also found a possible mechanism for this reaction.
- Zhang, Minmin,Yu, Shuowen,Hu, Fangzhi,Liao, Yijun,Liao, Lihua,Xu, Xiaoying,Yuan, Weicheng,Zhang, Xiaomei
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supporting information
p. 8757 - 8760
(2016/07/15)
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- Ru-catalyzed asymmetric hydrogenation of δ-keto Weinreb amides: Enantioselective synthesis of (+)-Centrolobine
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An efficient asymmetric hydrogenation of δ-keto Weinreb amides catalyzed by a Ru-Xyl-SunPhos-Daipen bifunctional catalyst has been achieved. This method afforded a series of enantio-enriched δ-hydroxy Weinreb amides in good yields (up to 93%) and enantioselectivities (up to 99%). This protocol was successfully applied to the synthesis of the key intermediate of (+)-Centrolobine.
- Zhao, Mengmeng,Lu, Bin,Ding, Guangni,Ren, Kai,Xie, Xiaomin,Zhang, Zhaoguo
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p. 2723 - 2730
(2016/03/05)
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- Copper-Catalyzed Oxidative Cyclization of Carboxylic Acids
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A method for converting C-H to C-O bonds through oxidative cyclization of carboxylic acids to generate lactone products is described. The reaction employs catalytic amounts of Cu(OAc)2 and potassium persulfate as the terminal oxidant and is performed open to air in an aqueous acetic acid solvent system. Preliminary mechanistic studies suggest that substrate oxidation likely proceeds by sulfate radical anion and that the Cu catalyst has no influence on the product-determining step. These conclusions differ from related investigations that propose the intermediacy of a carboxylate radical.
- Sathyamoorthi, Shyam,Du Bois
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supporting information
p. 6308 - 6311
(2016/12/23)
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- Visible-Light-Promoted Metal-Free Aerobic Oxidation of Primary Amines to Acids and Lactones
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A unique metal-free aerobic oxidation of primary amines via visible light photocatalytic double carbon–carbon bonds cleavage and multi carbon–hydrogen bonds oxidation was observed. Aerobic oxidation of primary amines could be controlled to afford acids by using dioxane with 18 W CFL, and lactones by using DMF with 8 W green LEDs, respectively. A plausible mechanism was proposed based on control experiments. This observation showed direct evidences for the fragmentation in the aerobic oxidation of aliphatic primary amines.
- Cheng, Xiaokai,Yang, Bo,Hu, Xingen,Xu, Qing,Lu, Zhan
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supporting information
p. 17566 - 17570
(2016/11/29)
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- Enhanced structural variety of nonplanar N-oxyl radical catalysts and their application to the aerobic oxidation of benzylic C-H bonds
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The design and synthesis of structurally variable, nonplanar N-oxyl radical catalysts and their application to the aerobic oxidation, etherification, and acetoamidation of benzylic C-H bonds are described. The catalytic oxidation of C-H bonds represents a powerful tool to synthesize oxygenated functional molecules from simple hydrocarbons in a straightforward way. Electron-deficient N-oxyl radical catalysts, such as phthalimidoyl N-oxyl (PINO) radical, generated from N-hydroxyphthalimide (1), have attracted much attention because of their applications in the oxidation of C-H bonds with high bond dissociation energy (BDE). However, a few sites in 1 are available for structural modifications and improvements of the catalytic performance. By replacing one carbonyl group in 1 with a trifluoromethyl (CF3)-substituted sp3-carbon, we generated an additional tunable site and a nonplanar backbone, while retaining the desirable electron-withdrawing properties and increasing the lipophilicity with respect to 1. We synthesized a variety of N-hydroxy pre catalysts containing such a CF3 moiety, and investigated their utility in the aerobic oxidation of benzylic C-H bonds. Precatalysts with electron-withdrawing substituents, such as trifluoroethoxy and the acetophenone moieties, afforded higher yields than a corresponding methoxy-substituted analogue. The introduction of substituents at the aromatic ring was also effective, as evident from the performance of 7-CF3 and 4,5,6,7-tetrafluoro precatalysts. Especially the combination of trifluoroethoxy- and 4,5,6,7-tetrafluoro substitution afforded a superior performance. These catalyst systems exhibited high functional group tolerance during the aerobic oxidation of C-H bonds, and benzylic etherification and Ritter-type reactions could be carried out at room temperature when a selected precatalyst and N-bromosuccinimide (NBS) were used.
- Kadoh, Yoichi,Oisaki, Kounosuke,Kanai, Motomu
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p. 737 - 753
(2016/07/13)
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- Synthesis of novel building blocks of benzosuberone bearing coumarin moieties and their evaluation as potential anticancer agents
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A series of novel benzosuberone bearing coumarin moieties 5a-c have been synthesized and their structures were determined by analytical and spectral (FT-IR, 1H NMR, 13C NMR, HRMS) studies. The newly synthesized compounds were evaluated for their cytotoxicity against four human cancer cell lines, A549 (Human alveolar adenocarcinoma cell line), HeLa (Human cervical cancer cell line), MDA-MB-231 (Human breast adenocarcinoma cell line), MCF-7 (Human breast adenocarcinoma cell line) and normal cell line HEK293 (Human embryonic kidney cell line). Compound 5a exhibited promising cytotoxicity with IC50 values ranging from 3.35 to 16.79 μM against all the cancer cell lines like A549, HeLa, MCF-7 and MDA-MB-231, while compound 5c showed significant cytotoxicity against HeLa and MDA-MB-231 with IC50 values of 6.72 and 4.87, respectively.
- Yadagiri, Bandi,Holagunda, Uma Devi,Bantu, Rajashaker,Nagarapu, Lingaiah,Kumar, C. Ganesh,Pombala, Sujitha,Sridhar
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p. 260 - 265
(2014/05/06)
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- Methods for the synthesis of chiral sulfur heterocycles and their application in the asymmetric Baylis-Hillman reactions
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Enantiomerically pure (2S,6S)-2,6-diphenyltetrahydro-2H-thiopyran, (2S)-2-phenyltetrahydro thiophene, and (2S)-2-phenyltetrahydro-2H-thiopyran were prepared in 70-72% yields and with 86-99% ee via cyclization of the corresponding dimesylate in an SN2 cyclization reaction using sodium sulfide nonahydrate. The results on the application of various chiral sulfides in asymmetric Baylis-Hillman reactions are also described.
- Periasamy, Mariappan,Gurubrahamam, Ramani,Muthukumaragopal, Gopal P.
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p. 568 - 574
(2013/06/27)
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- Efficient and convenient method for workup of ozonolysis reaction using sodium hydrosulfite
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An efficient and convenient method is reported for reductive workup of the ozon-olysis reaction using sodium hydrosulfite. Comparisons were made between triethylamine and methyl sulfide for their use as a quenching reagent in the ozonolysis of a variety of alkenes. Taylor & Francis Group, LLC.
- Tyagi, Vipin,Gupta, Ashok Kumar
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experimental part
p. 843 - 848
(2012/02/01)
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- Facile aerobic photooxidative oxylactonization of oxocarboxylic acids in fluorous solvents
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We developed efficient aerobic photooxidative oxylactonizations of oxocarboxylic acids promoted by trifluoroacetic anhydride with molecular oxygen as the terminal oxidant in the fluorous solvent FC-72.
- Tada, Norihiro,Cui, Lei,Ishigami, Takafumi,Ban, Kazunori,Miura, Tsuyoshi,Uno, Bunji,Itoh, Akichika
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p. 3007 - 3009,3
(2020/09/16)
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- NEW CCR2 RECEPTOR ANTAGONISTS AND USES THEREOF
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The present invention relates to novel antagonists for CCR2 (CC chemokine receptor 2) and their use for providing medicaments for treating conditions and diseases, especially pulmonary diseases like asthma and COPD.
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Page/Page column 45
(2012/01/14)
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- Oxidative cleavage of alkenes using an in situ generated iodonium ion with oxone as a terminal oxidant
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A facile and operationally convenient catalytic procedure for oxidative cleavage of alkenes is described. In situ formed [hydroxy(4-carboxyphenyl) iodonium]ion, 2, from the oxidation of 4-iodobenzoic acid, 1, has been shown to facilitate the cleavage of a variety of alkenes in presence of Oxone as a co-oxidant. Optimization of the reaction conditions using 1-phenyl-1- cyclohexene, 3, and the competitive oxidative cleavage of different substrates using the optimized conditions has uncovered important mechanistic details of the reaction.
- Thottumkara, Prem P.,Vinod, Thottumkara K.
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supporting information; experimental part
p. 5640 - 5643
(2011/02/27)
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- Synthesis and anti-inflammatory activity of some 3-(4,6-disubtituted-2- thioxo-1,2,3,4-tetrahydropyrimidin-5-yl) propanoic acid derivatives
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A series of 3-(4,6-disubtituted-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl) propanoic acid derivatives has been synthesized by condensation of thiourea, 5-(4-subtituted phenyl)-5-oxopentanoic acid and substituted aldehyde. The synthesized compounds were screened for their anti-inflammatory activity using rat paw edema method. Most of the compounds from the series showed significant (p 0.05) anti-inflammatory activity.
- Mokale, Santosh N.,Shinde, Sandeep S.,Elgire, Rupali D.,Sangshetti, Jaiprakash N.,Shinde, Devanand B.
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experimental part
p. 4424 - 4426
(2010/09/09)
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- The use of tethered addends to decrease the number of isomers of bisadduct analogues of PCBM
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Roped in: The number of isomers present in the bisadduct analogue PCBM (bis-PCBM; PCBM=phenyl-C61-butyric acid methyl ester) a recently introduced acceptor for bulk heterojunction organic photovoltaic devices has been reduced to seven by linking two tosylhydrazone addends with an ethylene glycol tether and reacting them with C60.
- Bouwer, Ricardo K. M.,Hummelen, Jan C.
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supporting information; experimental part
p. 11250 - 11253
(2010/11/02)
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- Benzylic carbon oxidation by an in situ formed o-iodoxybenzoic acid (IBX) derivative
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Benzylic C-H bonds are selectively oxidized to the corresponding carbonyl functionalities using catalytic quantities of 2-iodobenzoic acid (2IBAcid) and Oxone. The reported procedure tolerates different functional groups and operates under mild conditions. A radical mechanism is proposed for the transformation and evidence supporting the proposed mechanism is also presented. Georg Thieme Verlag Stuttgart.
- Ojha, Lawanya R.,Kudugunti, Shashi,Maddukuri, Padma P.,Kommareddy, Amitha,Gunna, Meena R.,Dokuparthi, Praveen,Gottam, Hima B.,Botha, Kiran K.,Parapati, Divya R.,Vinod, Thottumkara K.
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scheme or table
p. 117 - 121
(2009/05/30)
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- Enantioselective synthesis of Indolizidines bearing quaternary substituted stereocenters via rhodium-catalyzed [2 + 2 + 2] cycloaddition of alkenyl Isocyanates and terminal alkynes
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An enantioselective synthesis of Indolizidines bearing quaternary substituted stereocenters by way of a rhodium-catalyzed [2 + 2 + 2] cycloaddition of substituted alkenyl Isocyanates and terminal alkynes Is described. The reaction provides lactam products using aliphatic alkynes, whereas aryl alkynes give rise to vlnylogous amide products. Through modification of the phosphoramldlte llgand, high levels of enantloselectlvlty, regloselectlvlty, and product selectivity are obtained for both products.
- Lee, Ernest E.,Rovis, Tomislav
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supporting information; body text
p. 1231 - 1234
(2009/04/07)
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- A synthesis of 6-azabicyclo[3.2.1]octanes. The role of N-substitution
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(Chemical Equation Presented) The intramolecular cyclization reactions of aziridines with π-nucleophiles can be a useful route to a number of heterocyclic and carbocyclic ring systems. We were particularly interested in the use of this cyclization reaction for the synthesis of 6-azabicyclo[3.2.1] octanes. We report here the development of a new synthesis of the aziridine necessary for the aziridine-π-nucleophile cyclization. We also report on the cyclization of aziridines with three different substitutions on the aziridine nitrogen. We have found that N-diphenylphospinyl and N-H aziridines, while participating in the initial ring-opening reaction, do not lead to the desired bicyclic ring systems. In contrast, a nosyl group on the aziridine nitrogen leads efficiently to the bicyclic ring system and can be readily deprotected.
- Pulipaka, Aravinda B.,Bergmeier, Stephen C.
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p. 1462 - 1467
(2008/09/17)
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- Reaction of epoxyketones with hydrogen peroxide - Ethane-1,1- dihydroperoxide as a surprisingly stable product
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Reaction of epoxyketones with hydrogen peroxide, ethane-1,1-dihydroperoxide as a stable product was reported. Triacetone triperoxide and methylhydroperoxide were reported as highly explosive compounds. Thermogravimetric investigations showed decomposition in the temperature range 60-130°C with the highest decomposition rate at about 105°C. Using differently substituted epoxyketones as reactants, it was able to isolate and characterize propane-1,1-dihydroperoxide. Epoxyketones can also be attacked by H2O2 at the carbonyl C atom and at both epoxy C atoms as electrophilic centers. Initial results revealed that the acid-catalyzed reaction of 5- and 7-ring homologues 1 (n=0,2) with H2O2 runs similarly. They also show a lower tendency to form the geminal dihydroperoxide.
- Hamann, Hans-Juergen,Bunge, Alexander,Liebscher, Juergen
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scheme or table
p. 6849 - 6851
(2009/07/10)
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- Magnesium/Methanol: An Effective Reducing Agent for Peroxides
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Magnesium in methanol is an effective reagent for the chemoselective reduction of peroxides, including ozonides. Mg/MeOH is significantly more reactive than Me2S or PPh3 and somewhat more reactive than Zn/HOAc.
- Dai, Peng,Dussault, Patrick H.,Trullinger, Tony K.
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p. 2851 - 2852
(2007/10/03)
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- Nucleophilic benzoylation using lithiated methyl mandelate as a synthetic equivalent of the benzoyl carbanion. Oxidative decarboxylation of α-hydroxyacids
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The synthesis of alkyl aryl ketones using lithiated methyl mandelate as a synthetic equivalent of the benzoyl carbanion is reported (Umpolung). The methodology involves alkylation of methyl mandelate, hydrolysis of the ester group and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co(III) complex in the presence of pivalaldehyde under very mild and advantageous conditions. The procedure is also applied to methyl mandelates substituted on the aromatic ring.
- Blay, Gonzalo,Fernández, Isabel,Formentin, Pilar,Monje, Belén,Pedro, José R,Ruiz, Rafael
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p. 1075 - 1081
(2007/10/03)
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- Remote stereocontrol as a synthetic strategy: Diastereoselective annulations on an arene tricarbonylchromium template
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Stereoselective annulations on Cr(CO)3 complexed tetralone and benzosuberone derivatives have been achieved. Diastereomeric products are shown to be related by an epimerisable chiral centre. An unusually facile de-ethoxycarbonylation has been observed.
- Sur, Surojit,Ganesh, Sambasivam,Puranik, Vedavati G.,Sarkar, Amitabha
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p. 977 - 982
(2007/10/03)
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- A convenient synthesis of 1-phenyl-heptane-1,5-dione
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An efficient synthesis of the title compound 9 has been developed via Friedel-Craft acylation of benzene and subsequent manipulation of the functionalities of the condensation product 3 for generation of the required 1,5-dione moiety.
- Hassarajani, S. A.,Dhotare, B.,Chattopadhyay, A.,Mamdapur, V. R.
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- Catalytic aerobic oxidative decarboxylation of α-hydroxy-acids. Methyl mandelate as a benzoyl anion equivalent
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The monomeric square-planar cobalt(III) complex of bis-N,N'- disubstituted oxamides catalyses the oxidative decarboxylation of α-hydroxy acids with molecular oxygen/pivalaldehyde with very good yields. This reaction offers an interesting alternative in the use of methyl mandelate as a convenient benzoyl anion equivalent.
- Blay, Gonzalo,Fernandez, Isabel,Formentin, Pilar,Pedro, Jose R.,Rosello, Antonio L.,Ruiz, Rafael,Journaux, Yves
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p. 3327 - 3330
(2007/10/03)
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- Ethyl Mandelate as a Convenient New Benzoyl Anion Equivalent
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Ethyl mandelate acts as a convenient benzoyl anion equivalent for the formation of alkyl aryl ketones by deprotonation-alkylation followed by flash vacuum pyrolysis.
- Aitken, R. Alan,Thomas, Andrew W.
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p. 293 - 294
(2007/10/03)
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- Consecutive 6-endo trigonal cyclisations from polyene acyl radical intermediates leading to decalone and perhydrophenanthrone ring constructions
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A range of substituted Se-phenyl 5,9-dieneselenoates, viz. 15a, 25, 26, 27, 42 and 52, have been synthesised and their reactions with Bu3SnH-AIBN investigated.The diene esters 15a, 42 and 52 are shown to lead to decalone and to perhydrophenanthrone derivatives, viz. 19, 43 and 53, respectively, via consecutive 6-endo trig modes of cyclisations starting from the corresponding 5,9-diene acyl radical intermediates.By contrast, the 5,9-dienoates 25 and 27 lacking alkyl substitution at C-9 instead underwent cyclisation to the indanones 36 and 37, respectively, and the 6-methyl substituted analogue 26 produced only the cyclopentanone 38 on treatment with Bu3SnH-AIBN.
- Chen, Ligong,Gill, G. Bryon,Pattenden, Gerald,Simonian, Houri
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- Alkylarylketo acids
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Disclosed are novel alkylarylketocarboxylic acids and 5-substituted tetrazoles represented by the formula STR1 wherein Z is aryl or an alkyl of the structure STR2 W is a carboxyl moiety or a tetrazole moiety bound to Z at the 5-position of the tetrazole; R1 is C4 -C12 alkyl where Z is aryl and X is oxygen or is C5 -C12 alkyl where Z is alkyl and where Z is aryl and X is a bond; R2 and R3 are each independently hydrogen, C1 -C4 alkyl, hydroxy, C1 -C4 alkoxy, halogen, trihalomethyl, nitro, cyano or C1 -C4 acyl; R4, R5, R6 and R7 are each independently hydrogen or C1 -C4 alkyl or R4 and R6 or R5 and R7 can combine to form a carbocyclic ring; X is oxygen, or a bond at the ortho or para position; m is 0, 1 or 2; and n is 0 or 1, and nontoxic, pharmaceutically acceptable addition salts and carboxylic acid esters thereof.
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- Dispiroketals in Synthesis (Part 19): Dispiroketals as Enantioselective and Regioselective Protective Agents for Symmetric Cyclic and Acyclic Polyols.
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The enantioselective preparation of both enantiomers of a C2-symmetric diphenyl-bidihydropyran 3 and 4 is described.The application of enantiopure bi-dihydropyrans 1-4 towards the simultaneous enantioselective differentiation and regioselective protection of a range of cyclic and acyclic symmetrical polyols (23, 37, 43, 45, 54, 61 and 66) is investigated.Several deprotections utilising trifluoroacetic acid (TFA) and a transketalisation with acidic glycerol are presented.
- Downham, Robert,Edwards, Paul J.,Entwistle, David A.,Hughes, Andrew B.,Kim, Kun Soo,Ley, Steven V.
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p. 2403 - 2440
(2007/10/03)
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- The mechanistic study and synthetic applications of the base treatment in the ozonolytic reactions
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The E1cb mechanism is the overwhelming process in the reaction of bases and ozonides. As a quenching agent in the ozonolysis of a variety of alkenes, the reactions involving triethylamine often gave better yields and proceeded faster than those involving methyl sulfide. On the other hand, in the presence of 4 A molecular sieves, the secondary amines reacted with mono- and 1,1-di-substituted ozonides to afford the reductive amination products in high yields. The formation of ammonium formate in the reaction mixture also supported the E1cb mechanism in the reaction of ozonide and amine.
- Hon, Yung-Son,Lin, Sheng-Wun,Lu, Ling,Chen, Yao-Jung
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p. 5019 - 5034
(2007/10/02)
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- A convenient and efficient workup of ozonolysis reactions using triethylamine
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Comparisons were made between triethylamine and methyl sulfide for their use as a quenching agent in the ozonolysis of a variety of alkenes. The reactions involving triethylamine often gave better yields and proceeded faster than those of involving methyl sulfide. The role of triethylamine played as base instead of reducing agent in the reaction.
- Hon,Lin,Chen
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p. 1543 - 1553
(2007/10/02)
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- DIRECT SYNTHESIS OF δ-LACTONES FROM 2-(3-LITHIOPROPYL)-1,3-DIOXOLANE AND CARBONYL COMPOUNDS
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The reaction of 2-(3-lithiopropyl)-1,3-dioxolane (2), prepared in situ by lithiation of the chloroacetal 1 with lithium naphthalenide at -78 deg C, with aldehydes and ketones followed by hydrolysis with hydrochloric acid and final oxidation with PCC or Jones reagent yields the corresponding δ-lactones 5.
- Ramon, Diego J.,Yus, Miguel
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p. 3767 - 3770
(2007/10/02)
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- CONJUGATE ADDITION OF IMIDAZOLINES:A PROTOCOL FOR 1,4-ADDITION TO ENONES AND OTHER ACCEPTORS
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The enaminoester 1-benzyl-2-ethoxycarbonylmethyleneimidazolidine reacts with α,β-enones and other Michael acceptors to give 1,4-adducts; removal of the ethoxycarbonyl group completes overall conjugate addition of the imidazoline α-anion (which itself adds 1,2 to enones),and hydrolysis affords carboxylic acids.
- Jones, Raymond C. F.,Hirst, Simon C.
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p. 5361 - 5364
(2007/10/02)
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- REACTION OF α,β-UNSATURATED ALDEHYDES WITH HYDROGEN PEROXIDE CATALYSED BY BENZENESELENINIC ACIDS AND THEIR PRECURSORS
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Oxidation of α,β-unsaturated aldehydes with hydrogen perixide catalysed by benzeneselenic acids and their precursors has been investigated.Bis 2-nitrophenyl diselenide has proved to be the most effective catalyst.The major products resulting from the oxidation are vinyl formates (a) which on hydrolysis give saturated aldehydes or ketones (g) having the carbon chain shortened by one carbon atom, compared with the starting aldehydes.The minor products are formyloxyoxiranes (b), α-hydroxycarbonyl (e) and α-formyloxycarbonyl (f) compounds with the carbon chain shortened by one carbon atom.Carbonyl compounds d, formally derived from an oxidative fission of the carbon-carbon double bond, have been also isolated.Diformyloxy (4c) and formyloxyacetoxy phenylmethane (5c) have been isolated when cinnamaldehyde (4) or 1-phenyl-2-formyloxypropane (5a) were oxidized, respectively.Possible mechanisms of formation of these products are discussed.Similar products resulted when α,β-unsaturated aldehydes were oxidized with organic peroxy acids.
- Syper, Ludwik
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p. 2853 - 2872
(2007/10/02)
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- Tricyclic dihydropyridazinones and pharmaceutical compositions containing them
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The tricyclic dihydropyridazinone derivatives having formula I STR1 are endowed with interesting hypotensive, vasodilating, antiaggregant, antithrombotic and cytoprotective properties and are therefore useful in human or veterinary medicine.
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- Microbial Degradation Products from Biphenyl-related Compounds
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A soil isolate, strain S93BI, identified as Pseudomonas cruciviae could grown on more than ten biphenyl-related compounds including p-chlorobiphenyl.Biphenyl was converted to benzoic acid and γ-benzoylbutyric acid.Mono-substituted biphenyl compounds such as o-bromobiphenyl, p-chlorobiphenyl, o-nitrobiphenyl and m-nitrobiphenyl were converted to o-bromobenzoic acid, p-chlorobenzoic acid, o-nitrobenzoic acid and m-nitrobenzoic acid, respectively.Phenol and 2-phenoxymuconic acid were produced on the degradation of biphenyl ether.The formation of 2-phenoxymuconic acid demonstrated that biphenyl ether was degraded through an ortho cleavage pathway and the formation of γ-benzoylbutyric acid suggested the degradation of biphenyl through a meta cleavage pathway.
- Takase, Ichiro,Omori, Toshio,Minoda, Yasuji
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p. 681 - 686
(2007/10/02)
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- THE DOUBLE SIMMONS-SMITH REACTIONS VIA SILATROPIES
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The cyclopropanation of ethyl 3-trimethylsiloxy-2-alkenoates with the Simmons-Smith reagent, followed by ring cleavage and hydrolysis with an alkali solution, gave the corresponding 3-methyl-4-oxoalkanoic acids and 5-oxoalkanoic acids.
- Saigo, Kazuhiko,Yamashita, Takashi,Hongu, Akinori,Hasegawa, Masaki
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p. 715 - 722
(2007/10/02)
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- Aspects of Tautomerism. 13. Alkaline Hydrolysis of γ-, δ-, and ε-Keto Esters and their Desoxy Analogues. Geometrical Constraints on Keto Participation
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The rates of alkaline hydrolysis of methyl β-benzoylpropionate (I), methyl γ-benzoylbutyrate (II) and methyl δ-benzoylvalerate (III) decrease in the order I>II>III.Keto participation is the predominant pathway in the case of γ-keto esters.Evidence has also been obtained for keto participation in the case of δ-keto esters, whereas no such evidence is available in the case of ε-keto esters studied.
- Bhatt, M. Vivekananda,Ravindranathan, M.,Somayaji, Viswanatha,Rao, G. Venkoba
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p. 3170 - 3173
(2007/10/02)
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- Liquid Crystalline Properties of Cholesteryl ω-Arylalkanoates
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The thermal properties of the homologous series of cholesteryl ω-(4-benzoylphenyl)- (I), ω-(4-benzylphenyl)- (II), ω-benzoyl- (III), and ω-phenoxyalkanoate (IV) have been investigated.For series I and II the cholesteric-isotropic (Ch-I) transition temperatures, enthalpies, and entropies show a remarkable alternation.For series III and IV, the transition temperatures, enthalpies, and entropies exhibit weak alternation and their trends are opposite to those for series I and II, and the cholesteryl ω-phenylalkanoates.The cholesteric-isotropic transition temperatures are discussed in terms of the geometrical and electrical alternations stemming from the terminal aryl groups, and also the relative importance between these two terms.
- Koden, Mitsuhiro,Miyake, Shiro,Takenaka, Shunsuke,Kusabayashi, Shigekazu
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p. 2387 - 2390
(2007/10/02)
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- Synthesis and X-Ray Analysis of 2,3,5,6,11-Pentaoxabicycloundecanes
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The reactions of bicyclic ozonides and aldehyde- or ketone-derived peroxides, performed or generated in situ, in the presence of chlorosulphonic acid afford the corresponding 2,3,5,6,11-pentaoxabicycloundecanes.In addition, 1,2,4,5-tetraoxans are often isolated from the product mixture.Mechanisms are proposed to account for the observed peroxidic products.An X-ray analysis of the crystalline product (4b) confirms the general structure and reveals that it is solely the exo-isomer.
- Miura, Masahiro,Ikegami, Akio,Nojima, Masatomo,Kusabayashi, Shigekazu,McCullough, Kevin J.,Walkinshaw, Malcolm D.
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p. 1657 - 1664
(2007/10/02)
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