- Novel human umbilical vein endothelial cells (HUVEC)-apoptosis inhibitory phytosterol analogues: Insight into their structure-activity relationships
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Design, synthesis and insight into the structure-activity relationships (SAR) of phytosterol analogues as novel antiapoptotic agents are described. In particular, the non-branched alkyl chain at C24 and the pseudosugar moiety at C3 hydroxyl group turned out crucial for the inhibition of human umbilical vein endothelial cells (HUVEC) apoptosis.
- Lee, Sujin,Marharjan, Sony,Jung, Jong-Wha,Kim, Nam-Jung,Kim, Kyeojin,Han, Young Taek,Lim, Changjin,Choi, Hyun-Jung,Kwon, Young-Geun,Suh, Young-Ger
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Read Online
- Utility of 3,4-Dimethoxybenzyl (DMPM) Glycosides. A New Glycosylation Triggered by 2,3-Dichloro-5,6-dicyano-p-benzoquinone (DDQ) Oxidation
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A new glycosylation which proceeds through the formation of charge transfer (CT) complex of DMPM glycosides with DDQ followed by the oxidation-triggered fragmentation of the intermediates has been developed.Primary, secondary, and tertiary alcohols are us
- Inanaga, Junji,Yokoyama, Yasuo,Hanamoto, Takeshi
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Read Online
- Highly selective tetrahydropyranylation/dehydropyranylation of alcohols and phenols using porous phenolsulfonic acid-formaldehyde resin catalyst under solvent-free condition
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An efficient protocol for solvent-free chemoselective tetrahydropyranylation/depyranylation of alcohols and phenols is reported herein using mesoporous Phenolsulfonic Acid Formaldehyde Resins as a heterogeneous acid catalyst. The catalyst successfully performed chemoselective protection and deprotection reactions of a wide range of substrates ranging from primary to secondary and tertiary alcohols and also phenols. The reactions were carried out at ambient temperature under solvent-free condition (SolFC) which resulted in high yields within a very short time. FT-IR, TEM, SEM, EDS and TG-DSC analysis techniques were employed to characterize the synthesized polymeric catalyst. The chemoselective nature of our method was confirmed using 13C DEPT-135 NMR studies. The polymer catalyst was found to be recoverable even after 10th catalytic cycle without much depreciation in its activity. The heterogeneity of the catalyst was verified by hot filtration method. Good yield, energy and cost- effective method, solvent-free protocol, mild reaction conditions, no inert atmosphere, metal-free heterogeneous polymer catalyst and excellent recoverability of the catalyst are notable milestones of the reported protocol.
- Rajkumari, Kalyani,Laskar, Ikbal Bahar,Kumari, Anupama,Kalita, Bandita,Rokhum, Lalthazuala
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- Aniline-terephthalaldehyde resin p-toluenesulfonic acid (ATRT) salt as efficient mild polymeric solid acid catalyst
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Aniline-terephthalaldehyde resin p-toluenesulfonic acid (ATRT) salt was easily prepared by the reaction of aniline with 1.25 equiv of terephthalaldehyde in the presence of 1.0 equiv of p-toluenesulfonic acid at 75 C for 24 h in EtOH. ATRT efficiently catalyzed the tetrahydropyranylation of alcohols and deprotection of tetrahydropyranyl (THP), triethylsilyl (TES), and tert-butyldimethylsilyl (TBDMS) ethers. Deprotection of dodecyl THP ether and dodecyl TBDMS ether catalyzed by ATRT proceeded faster than those by pyridinium p-toluenesulfonate (PPTS). ATRT was reused without significant loss of activities.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
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supporting information
p. 6740 - 6743
(2013/11/19)
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- NOVEL VASCULAR LEAK INHIBITOR
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The present disclosure relates to a novel vascular leakage inhibitor. The novel vascular leakage inhibitor of the present disclosure inhibits the apoptosis of vascular endothelial cells, inhibits the formation of actin stress fibers induced by VEGF, enhances the cortical actin ring structure, and improves the stability of the tight junctions (TJs) between vascular cells, thereby inhibiting vascular leakage. The vascular leakage inhibitor of the present disclosure has the activity of not only reducing vascular permeability but also recovering the integrity of damaged blood vessels. Accordingly, the vascular leakage inhibitor of the present disclosure can prevent or treat various diseases caused by vascular leakage. Since the vascular leakage inhibitor of the present disclosure is synthesized from commercially available or easily synthesizable cholesterols, it has remarkably superior feasibility of commercial synthesis.
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Page/Page column 21
(2012/09/21)
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- [H2-Cryptand 222]2+(Br3-) 2 as a tribromide-type catalyst for the trimethylsilylation/ tetrahydropyranylation of alcohols
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A stable organic tribromide, [H2-cryptand 222] 2+(Br3-)2 was utilized as an active catalyst for the trimethylsilylation/ tetrahydropyranylation of alcohols. The method is general for the preparation of OH-protected aliphatic (acyclic and cyclic), aromatic, primary, secondary and tertiary alcohols.
- Chehardoli, Gholamabbas,Zolfigol, Mohammad Ali,Khakyzadeh, Vahid,Gholami, Hadi,Niknam, Khodabakhsh
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experimental part
p. 127 - 131
(2012/06/18)
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- Cholesterol-derived novel anti-apoptotic agents on the structural basis of ginsenoside Rk1
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Design and synthesis of cholesterol-derived anti-apoptotic agents were described. The synthesized cholesterol analogs designed on the structural basis of ginsenoside Rk1 inhibited the undesirable apoptosis of human endothelial cells, which are induced by
- Lee, Sujin,Maharjan, Sony,Kim, Kyeojin,Kim, Nam-Jung,Choi, Hyun-Jung,Kwon, Young-Guen,Suh, Young-Ger
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scheme or table
p. 7102 - 7105
(2011/01/03)
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- Photosensitized tetrahydropyran transfer
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(Chemical Equation Presented) THP ethers were formed cleanly during photolysis of 3,4-dihydro-2H-pyran, an alcohol, and catalytic 1,5-dichloro9,10-anthraquinone with use of visible light. The reaction could be conducted under ambient fluorescent lighting or with sunlight as well as in a Rayonet reactor. The scope and mechanism are discussed.
- Oates,Jones, Paul B.
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p. 4743 - 4745
(2008/09/21)
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- AI(OTf)3 - A highly efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
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A simple and highly efficient method has been developed for the tetrahydropyranylation of alcohols by their reaction with 3,4-dihydro-2H-pyran (DHP) using a catalytic amount (0.01-1 mol%) of aluminium triflate under solvent-free conditions. The effect of various factors like temperature, amount of the catalyst, and molar ratio of substrates on the reaction conditions has also been studied. The comparative study of tetrahydropyranylation of benzyl alcohol using various catalysts including some reported ones shows the efficiency of this catalyst.
- Kamal, Ahmed,Naseer A Khan,Srikanth,Srinivasa Reddy
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scheme or table
p. 1099 - 1104
(2009/03/11)
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- Efficient and ecofriendly protocol for tetrahydropyranylation/ depyranylation of alcohols in the presence of tin(II) chloride dihydrate
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A mild, efficient, and solvent-free protocol for tetrahydropyranylation of alcohols in the presence of a catalytic amount of SnCl2·2H2O is reported. Simple filtration of the reaction mixture through a short silica-gel pad gives the pure products in excellent yields. Depyranylation can also be achieved by adding methanol under similar reaction conditions. Copyright Taylor & Francis Group, LLC.
- Gogoi, Dipankoj,Baruah, Nabajyoti,Bez, Ghanashyam
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p. 595 - 599
(2007/10/03)
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- Silica-supported perchloric acid (HClO4-SiO2): A versatile catalyst for tetrahydropyranylation, oxathioacetalization and thioacetalization
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A simple and convenient synthetic protocol for the protection of hydroxyl group as tetrahydropyranyl ether as well as carbonyl functionality as oxathioacetal and thioacetal has been achieved using a catalytic amount of silica-supported perchloric acid und
- Khan, Abu T.,Parvin, Tasneem,Choudhury, Lokman H.
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p. 2497 - 2502
(2008/02/03)
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- Silica-gel-supported aluminium chloride: A stable, efficient, selective, and reusable catalyst for tetrahydropyranylation of alcohols and phenols
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A simple, effective, and highly chemoselective method to form 2-tetrahydropyranyl ethers of alcohols and phenols in the presence of silica-gel-supported aluminium chloride as a heterogeneous Lewis acid catalyst is described. The catalyst can be easily recovered and reused without appreciable change in its efficiency. Copyright Taylor & Francis Group, LLC.
- Borujeni, Kaveh Parvanak
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p. 2705 - 2710
(2007/10/03)
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- Tetrahydropyranylation and depyranylation of alcohols catalyzed by aqueous zinc tetrafluoroborate
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Aqueous solution of zinc tetrafluoroborate as an effective catalyst for tetrahydropyranylation and depyranylation of alcohols has been described. Copyright Taylor & Francis, Inc.
- Islam, Samimul,Majee, Adinath,Khan
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p. 1789 - 1793
(2007/10/03)
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- Convenient tetrahydropyranylation of alcohols and phenols by catalytic ferric sulfate hydrate (Fe2(SO4)3· xH2O)
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Ferric sulfate hydrate (Fe2(SO4)3· xH2O) is found to be an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols and phenols at ambient or near ambient temperature. In addition, selective monotetrahydropyranylation of symmetrical diols is achieved under similar conditions. The deprotection of THP ether and direct transformation of THP ether to the corresponding acetate by Fe 2(SO4)3·xH2O is also studied. The simplicity of manipulation, mild conditions, reusable catalyst, good selectivity, and environment benign characters make this method a good alternative way for the THP protection of alcohols.
- Li, Lingjun,Zhu, Lizhi,Zhang, Xinying,Zhang, Guisheng,Qu, Guirong
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p. 1120 - 1123
(2007/10/03)
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- Silylation and tetrahydropyranylation of alcohols catalyzed by Al(HSO 4)3
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Trimethylsilylation and tetrahydropyranylation of alcohols are efficiently catalyzed by Al(HSO4)3. All reactions were performed under mild and completely heterogeneous conditions in good-to-high yields.
- Shirini, Farhad,Zolfigol, Mohammad Ali,Abedini, Masoumeh
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p. 1982 - 1985
(2007/10/03)
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- A highly efficient synthetic protocol for tetrahydropyranylation/ depyranylation of alcohols and phenols
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Bismuth(III) nitrate pentahydrate [Bi(NO3)3· 5H2O] is found to be an effective catalyst for both tetrahydropyranylation and depyranylation of alcohols and phenols. Some of the major advantages of this protocol are: non-aqueous workup, good yields, the involvement of a less-expensive and nontoxic catalyst, and compatibility in the presence of a large number of other protecting groups. Notably, isopropylidene, benzylidene, and thioacetal groups are also unaffected under the experimental conditions. Remarkably, a selective mono-protection of diols and primary alcohols can be achieved chemoselectively by employing the same catalyst. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
- Khan, Abu T.,Ghosh, Subrata,Choudhury, Lokman H.
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p. 4891 - 4896
(2007/10/03)
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- Synthesis of spermidinylcholestanol and spermidinylcholesterol, squalamine analogues
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Several novel squalamine-related polyaminosterols are reported. The synthesis of 7α-N-[3N-(4-aminobutyl)aminopropyl]aminocholestanol I, 6α-N-[3N-(4-aminobutyl)aminopropyl]aminocholestanol II, 7α and 7β-N-[3N-(4-aminobutyl)aminopropyl]aminocholesterol (III and IV), was accomplished from cholesterol, they provide the first examples in which spermidine is introduced in the B steroidal ring. These molecules showed comparable antibacteria and fungi activities to squalamine, and were cytotoxic on a human non-small cell bronchopulmonary carcinoma line (NSCLC-N6). Therefore, these molecules with antibiotic and cytotoxic activities are promising for immune-compromised patients in cancer chemotherapy. Graphical Abstract.
- Choucair, Bassima,Dherbomez, Michel,Roussakis, Cristos,El Kihel, La?la
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p. 11477 - 11486
(2007/10/03)
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- Efficient tetrahydropyranylation of alcohols and detetrahydropyranylation reactions in the presence of catalytic amount of trichloroisocyanuric acid (TCCA) as a safe, cheap industrial chemical
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Preparation and cleavage of THP ethers of different hydroxy functional groups are easily and efficiently performed in the presence of trichloroisocyanuric acid (TCCA) in the absence of solvent with high yields.
- Firouzabadi, Habib,Iranpoor, Nasser,Hazarkhani, Hassan
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p. 3623 - 3630
(2007/10/03)
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- Cupric sulfate pentahydrate (CuSO4·5H2O): A mild and efficient catalyst for tetrahydropyranylation/depyranylation of alcohols and phenols
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Various alcohols and phenols can be smoothly converted to the corresponding THP ethers using 20 mol % CuSO4·5H2O under mild reaction conditions at room temperature. Some of the major advantages of this procedure are nonaqueous work-up, very good yields, less expensive catalyst and compatibility with other protecting groups.
- Khan, Abu T.,Choudhury, Lokman H.,Ghosh, Subrata
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p. 7891 - 7894
(2007/10/03)
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- Phosphorus pentoxide as an efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
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A facile and efficient method for the preparation of tetrahydropyranyl ethers from alcohols is improved in solvent-free media. These reactions are catalyzed by P2O5 and afford various tetrahydropyranyl ethers in shorter reaction time, with good to excellent yields (75-95%) at room temperature. This method is also compatible with substrates containing acid-sensitive functional groups.
- Eshghi, Hossein,Shafieyoon, Parvaneh
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p. 2149 - 2152
(2007/10/03)
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- Microwave accelerated tetrahydropyranylation and detetrahydropyranylation of alcohols, phenols, and thiols catalyzed by hydrated zirconia
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A solvent free and expeditious method for tetrahydropyranylation and detetrahydropyranylation of alcohols, phenols and thiols is described using hydrated zirconia and 3,4-dihydro-2H-pyran (DHP). A comparison of this microwave-accelerated reaction with conventional heating condition is also presented.
- Gajare, Anil S.,Sabde, Dhananjay P.,Shingare, Murlidhar S.,Wakharkar, Radhika D.
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p. 1549 - 1555
(2007/10/03)
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- Acetonyltriphenylphosphonium bromide and its polymer-supported analogues as catalysts in protection and deprotection of alcohols as alkyl vinyl ethers
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Both acetonyltriphenylphosphonium bromide (ATPB, 1) and poly-p-styryldiphenylacetonylphosphonium bromide (A) were effective catalysts in the protection of alcohols as THP, THF, and EE ethers as well as the cleavage of THP, THF, and EE ethers to the corresponding alcohols. They could be applied to 1°, 2° and 3° alcohols, phenol and acid-labile alcohols. Both ATPB and catalyst A are excellent catalysts in the present study. It needed only 1×10-2-1.25×10-2 mol equiv. of the polymer-supported catalyst A in the reactions.
- Hon, Yung-Son,Lee, Chia-Fu,Chen, Rong-Jiunn,Szu, Ping-Hui
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p. 5991 - 6001
(2007/10/03)
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- Simple, facile and highly selective tetrahydropyranylation of alcohols using silica chloride
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A simple and efficient process for tetrahydropyranylation of alcohols has been developed by reacting with dihydropyran at room temperature in presence of catalytic amount of silica chloride. The process is highly selective for monoprotection of the hydroxyl groups of symmetric diols.
- Ravindranath,Ramesh,Das
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p. 1777 - 1778
(2007/10/03)
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- Ionic liquids as recyclable reaction media for the tetrahydropyranylation of alcohols
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A comparative study of the catalysed tetrahydropyranylation of 1-phenylethanol by p-toluenesulphonic acid (TsOH), pyridinium p-toluenesulphonate (PPTS) and triphenylphosphine hydrobromide (TPP.HBr) using 3,4-dihydro-2H-pyran in dichloromethane or in the i
- Branco, Luís C.,Afonso, Carlos A. M.
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p. 4405 - 4410
(2007/10/03)
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- Microwave assisted catalytic protection and deprotection of alcohols with 3,4-dihydro-2h-pyran
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Protection of alcohols as their 2-tetrahydropyranyl ethers and their subsequent hydrolysis can be easily achieved through a microwave irradiated reaction catalysed by iodine.
- Deka,Sarma
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p. 4435 - 4441
(2007/10/03)
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- Acetonyltriphenylphosphonium bromide in organic synthesis: An extremely efficient catalyst for the protection and deprotection of alcohols as alkyl vinyl ethers
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Acetonyltriphenylphosphonium bromide (ATPB) was an extremely effective catalyst in the preparation of THP, THF, and EE ethers as well as cleavage of THP, THF, and EE ethers to the corresponding alcohols. It could be applied to 1°, 2°and 3°alcohols and phenol.
- Hon, Yung-Son,Lee, Chia-Fu
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p. 2389 - 2392
(2007/10/03)
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- Zirconium sulfophenyl phosphonate as a heterogeneous catalyst in tetrahydropyranylation of alcohols and phenols
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Zirconium Sulfophenyl Phosphonate Zr(O3PCH3)(1.2)(O3PC6- InSO3H)(0.8) was found to be an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols and phenols.
- Curini, Massimo,Epifano, Francesco,Marcotullio, Maria Carla,Rosati, Ornelio,Costantino, Umberto
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p. 8159 - 8162
(2007/10/03)
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- Synthesis and preliminary in vitro evaluation of antitumor nitrosoureido cholesterol derivatives
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A new class of chloroethyl nitrosourea analogues of cholesterol has been synthetized from the corresponding 7-amino and 7-aminoalkylcholesterol derivatives. Compounds III-V inhibited L1210 cell growth in culture much more effectively than N,N'-bis(2-cgloroethyl)-N'-nitrosourea (BCNU) after 48 h incubation. Stability and cytotoxic activity of these prodrugs are promising for brain tumor treatments and as lymphotropic vectors for tumor cells spreading along the lymphatic pathways.
- Elkihel,Gelin,Letourneux
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p. 190 - 194
(2007/10/02)
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- Dicyanoketene ethylene acetal as a mild and efficient catalyst for tetrahydropyranylation of alcohols
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Alcohols can react with 3,4-dihydro-2H-pyran in the presence of a catalytic amount of dicyanoketene ethylene acetal under neutral conditions to afford the corresponding tetrahydropyranyl ethers in good yields.
- Miura,Masaki
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p. 1981 - 1987
(2007/10/02)
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- Catalysis of the Tetrahydropyranylation of Alcohols and Phenols by the H-MCM-41 Mesoporous Molecular Sieve
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The mesoporous H-MCM-41 molecular sieve is a mild and efficient catalyst for the title reaction, which can be carried out in a simple way and provides high selectivities within short reaction times.
- Kloetstra, K. Richard,Bekkum, Herman van
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- Molybdenum catalyzed protective tetrahydropyranylation of alcohols and phenols
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Molybdenyl(VI) acetylacetonate is an effective catalyst for the protective tetrahydropyranylation of alcohols and phenols.
- Lakshmi Kantam,Lakshmi Santhi
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p. 2225 - 2228
(2007/10/02)
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- Lanthanum trichloride catalysed protective tetrahydropyranylation of alcohols and phenols
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Lanthanum Trichloride is an effective catalyst for the protective tetrahydropyranylation of alcohols and phenols. The catalyst is recycled almost quantitatively.
- Bhuma,Kantam
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p. 2941 - 2944
(2007/10/02)
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- 2,3-Dichloro-5,6-dicyano-p-benzoquinone as a Mild and Efficient Catalyst for the Tetrahydropyranylation of Alcohols
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Hydroxy compounds readily add to 3,4-dihydro-2H-pyran under neutral conditions in the presence of a catalytic amount of 2,3-dichloro-5,6-dicyano-p-benzoquinone, to give high yields of the corresponding tetrahydropyranyl ethers.
- Tanemura, Kiyoshi,Horaguchi, Takaaki,Suzuki, Tsuneo
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p. 304 - 305
(2007/10/02)
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- A New, Mild Heterogeneous Catalyst for the Tetrahydropyranylation of Alcohols and Phenols
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The hydrochloride salt of a cross-linked macroreticular poly(4-vinylpyridine) resin in bead form is an effective, yet mild acid catalyst for the tetrahydropyranylation of alcohols (primary, secondary, and tertiary) and phenols.The reaction is carried out in the presence of excess dihydropyran without the formation of troublesome oligomeric pyrans.High yields of the desired ethers are obtained even in reactions with alcohols having steric restrictions or acid sensitive amine functionalities.
- Johnston, Richard D.,Marston, Charles R.,Krieger, Paul E.,Goe, Gerald L.
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p. 393 - 394
(2007/10/02)
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- Catalysis by Acidic Clay of the Protective Tetrahydropyranylation of Alcohols and Phenols
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The K-10 montmorillonite, a readily available and inexpensive industrial catalyst, cleanly effects the title reaction.
- Hoyer, Susanne,Laszlo, Pierre,Orlovic, Mirko,Polla, Eugenio
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p. 656 - 657
(2007/10/02)
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