- Zinc-catalyzed chemoselective reduction of esters to alcohols
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Economical alcohols! A general and chemoselective catalytic reduction of esters to alcohols using inexpensive zinc acetate and silanes has been developed. The operational simplicity and the high functional group tolerance, without the need for protecting and deprotecting steps, make this procedure particularly attractive for organic synthesis. Copyright
- Das, Shoubhik,Moeller, Konstanze,Junge, Kathrin,Beller, Matthias
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- A Mild Oxidation of Aromatic Amines
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Several primary aromatic amines have been converted to the corresponding nitro compounds in good yields.The oxidant was oxone (potassium peroxymonosulfate) and the reactions were performed in 5 to 20percent aqueous acetone and buffered with sodium bicarbonate.
- Webb, Kevin S.,Seneviratne, Viran
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- Electrochemically induced titanocene-mediated reductive opening of epoxides
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A new method for chemo- and regioselective electrochemical reductive opening of epoxides yielding primary alcohols with titanocene dichloride as a catalyst has been elaborated.
- Nikitin, Oleg M.,Magdesieva, Tatiana V.
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- Piers' borane-mediated hydrosilylation of epoxides and cyclic ethers
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We report the first diarylborane-catalysed hydrosilylation of epoxides and cyclic ethers. Mechanistic studies on the in situ generated Piers' borane (C6F5)2BH with hydrosilanes in the presence of an epoxide revealed that an alkyloxy(diaryl)borane (C6F5)2BOR is readily formed as a catalytically competent species for the outer-sphere hydrosilylation of epoxides and cyclic ethers.
- Zhang, Jianbo,Park, Sehoon,Chang, Sukbok
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- Photohydration of Aromatic Alkenes and Alkynes
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The photohydrations of aromatic alkenes and alkynes 2-12 have been studied in aqueous sulfuric acid.For the nonnitro-substituted substrates 2-8, the products are the compounds obtained via Markovnikov addition of water to the alkene or alkyne moiety.Nitro-substituted styrenes 11 and 12 and phenylacetylenes 9 and 10 gave anti-Markovnikov addition products.Product quantum yields (Ψpdt) generally show a strongly sigmoidal dependence on the activity of the medium, with the exception of the nitrostyrenes, where no such dependence was observed.For compounds 2-8, quenching of fluorescence with increasing acidity was observed, and the proposed photohydration mechanism involves a rate-limiting protonation step on the first excited singlet state (S1), while for the nitrostyrenes, a rate-limiting attack of water on T1 is consistent with the available data.A mechanism involving a concerted addition of H3O+ to T1 is proposed for the photohydration of (nitrophenyl)acetylenes 9 and 10.The solvent isotope effect on the product quantum yield (ΨH/ΨD) is consistent with these proposals.Photoprotonation rate constants (kH) have been obtained - via transient and steady state measurements - for substrates 2, 4-6, and 8.Alkenes are approximately ane order of magnitude less reactive than alkynes to photoprotonation, both of which are 1011 - 1014 times more reactive than the corresponding ground-state molecules.
- Wan, Peter,Culshaw, Stephen,Yates, Keith
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- One-Carbon Homologation of Primary Alcohols and the Reductive Homologation of Aldehydes Involving a Jocic-Type Reaction
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(Trichloromethyl)carbinols, which are formed in one operation from either alcohols or aldehydes, can be converted into primary alcohols in a Jocic-type reaction involving LiBH4. The net result is a convenient two-step, one-carbon homologation of primary alcohols or a reductive one-carbon homologation of aldehydes featuring a broad substrate scope. The method is step-economical, and it nicely complements established one-carbon homologation strategies. (Trichloromethyl)carbinols, which are formed in one operation from either alcohols or aldehydes, can be converted into primary alcohols in a Jocic-type reaction involving LiBH4. The net result is a convenient two-step, one-carbon homologation of primary alcohols or a reductive one-carbon homologation of aldehydes featuring a broad substrate scope.
- Li, Zhexi,Gupta, Manoj K.,Snowden, Timothy S.
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- A method for preparing the amino ethanol (by machine translation)
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The invention discloses a method for preparing amino ethanol, comprising the following steps: (1) will be soluble in ethyl ether in nitrobenzene acetic acid, heated to 40 - 50 °C, under the protection of nitrogen, adding the hydrogenated lithium aluminum after uniformly mixing and stirring, dripping water, continuing the stirring 3 h, after the reaction is finished, the temperature dropped to 0 °C, add sodium hydroxide solution and water, standing 15 - 20 min after, temperature to room temperature, adding anhydrous MgSO4 , Stirring 20 - 30 min after filtering, the filtrate in the solvent evaporate, made to the nitrobenzene ethanol; (2) the prepared to the nitrobenzene ethanol dissolved in ethanol, adding catalyst, nitrogen, raising the temperature to 80 °C, the hydrogen gas under the atmospheric pressure, the reaction 2 - 3 h, filter after cooling, evaporate the ethanol, the obtained solid recrystallized after, vested the pairs amino ethanol. The application of the preparation method is safe and stable, low demand operating conditions, higher product yield. (by machine translation)
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Paragraph 0019-0057
(2018/06/12)
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- Antiproliferative activity and SARs of caffeic acid esters with mono-substituted phenylethanols moiety
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A series of CAPE derivatives with mono-substituted phenylethanols moiety were synthesized and evaluated by MTT assay on growth of 4 human cancer cell lines (Hela, DU-145, MCF-7 and ECA-109). The substituent effects on the antiproliferative activity were systematically investigated for the first time. It was found that electron-donating and hydrophobic substituents at 2′-position of phenylethanol moiety could significantly enhance CAPE's antiproliferative activity. 2′-Propoxyl derivative, as a novel caffeic acid ester, exhibited exquisite potency (IC50?=?0.4?±?0.02 & 0.6?±?0.03?μM against Hela and DU-145 respectively).
- Xie, Jin,Yang, Fengzhi,Zhang, Man,Lam, Celine,Qiao, Yixue,Xiao, Jia,Zhang, Dongdong,Ge, Yuxuan,Fu, Lei,Xie, Dongsheng
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p. 131 - 134
(2016/12/27)
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- Highly efficient protection of alcohols as trityl ethers under solvent-free conditions, and recovery catalyzed by reusable nanoporous MCM-41-SO3H
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An efficient method was developed for the protection of alcohols as trityl ethers using triphenylmethanol in the presence of nanoporous MCM-41-SO3H as a heterogeneous catalyst under solvent-free ball-milling at room temperature. Low catalyst loading, high efficiency, reusability are among the advantages of this new solvent-free and environmentally friendly method. The deprotection of the produced trityl ethers was also efficiently achieved using the same catalyst in wet acetonitrile.
- Gholamzadeh, Zeynab,Naimi-Jamal, Mohammad Reza,Maleki, Ali
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p. 994 - 1001
(2015/01/09)
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- Formal hydration of non-activated terminal olefins using tandem catalysts
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The hydration of terminal olefins to secondary alcohols has been achieved using a Pd(ii)/Ru(ii) catalyst combination with high regioselectivity and yields. Both vinyl arenes and aliphatic olefins can be hydrated easily with the tandem catalyst system using a low catalyst loading of 1 mol%. The Royal Society of Chemistry 2014.
- Yang, Yongsheng,Guo, Jiayi,Ng, Huimin,Chen, Zhiyong,Teo, Peili
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supporting information
p. 2608 - 2611
(2014/03/21)
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- CATALYTIC ANTI-MARKOVNIKOV OXIDATION AND HYDRATION OF OLEFINS
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The disclosure provides a dual-catalysis system for direct conversion of olefins to alcohols. The cooperative catalytic system contains one oxidizing catalyst and one transfer-hydrogenation catalyst. A wide variety of olefins, including aromatic and aliphatic olefins, can be used as the reactant. The transformation proceeds with anti-Markovnikov selectivity, and in some aspects provides primary alcohols as major products. The disclosure further provides a system for oxidation of olefins with anti-Markovnikov selectivity.
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Page/Page column 16
(2012/07/14)
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- Primary alcohols from terminal olefins: Formal anti-Markovnikov hydration via triple relay catalysis
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Alcohol synthesis is critical to the chemical and pharmaceutical industries. The addition of water across olefins to form primary alcohols (anti-Markovnikov olefin hydration) would be a broadly useful reaction but has largely proven elusive; an indirect hydroboration/oxidation sequence requiring stoichiometric borane and oxidant is currently the most practical methodology. Here, we report a more direct approach with the use of a triple relay catalysis system that couples palladium-catalyzed oxidation, acid-catalyzed hydrolysis, and ruthenium-catalyzed reduction cycles. Aryl-substituted terminal olefins are converted to primary alcohols by net reaction with water in good yield and excellent regioselectivity.
- Dong, Guangbin,Teo, Peili,Wickens, Zachary K.,Grubbs, Robert H.
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scheme or table
p. 1609 - 1612
(2012/02/01)
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- InBr3-catalyzed deoxygenation of carboxylic acids with a hydrosilane: Reductive conversion of aliphatic or aromatic carboxylic acids to primary alcohols or diphenylmethanes
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A simple and practical procedure for the direct reduction of aliphatic carboxylic acids with a variety of functional groups to a primary alcohol using the mild reducing reagent tetramethyldisiloxane (TMDS), in the presence of a catalytic amount of InBr3 has been developed. This simple reducing system, when used together with a hydrosilane, allows the preparation of the diphenylmethane derivative directly from an aromatic carboxylic acid and an aromatic compound. Copyright
- Sakai, Norio,Kawana, Keita,Ikeda, Reiko,Nakaike, Yumi,Konakahara, Takeo
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experimental part
p. 3178 - 3183
(2011/06/28)
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- Microwave-assisted synthesis of 5-substituted 2-aminothiophenes starting from arylacetaldehydes
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An easy three-step pathway for the synthesis of arylacet-aldehydes from the corresponding carboxylic acids in very high yields is described. Their use as precursors of 5-substituted-2-aminothiophenes is illustrated via a microwave-assisted Gewald reaction. This method allows obtaining the expected compounds in a shorter time and with better yields and purities than the classical procedures. Georg Thieme Verlag Stuttgart - New York.
- Revelant, Germain,Dunand, Sandrine,Hesse, Stephanie,Kirsch, Gilbert
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p. 2935 - 2940
(2011/11/01)
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- Synthesis of mycinose from 1,2:5,6-Di-O-isopropylidene-α-D- glucofuranose
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A facile synthesis of mycinose from commercially available 1,2:5,6-Di-O-isopropylidene-α-D-glucofuranose was developed. A selective and direct reductive debromination of α-hydroxy bromides in a simple NaBH4/EtOH/H2O system was found.
- Bao, Kai,Gao, Hao,Zhu, Zhibin,Wang, Jinhong,Zhang, Guoning,Sun, Jun,Zhang, Weige,Yao, Xinsheng
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scheme or table
p. 592 - 595
(2012/05/31)
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- Cobalt(II) chloride hexahydrate-diisopropylamine catalyzed mild and chemoselective reduction of carboxylic esters with sodium borohydride
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The cobalt-catalyzed reduction of unsaturated α-cyano carboxylic esters using sodium borohydride (NaBH4) leads to the corresponding saturated cyano alcohols in high yields. In particular, the new catalytic system cobalt(II) chloride-diisopropylamine in combination with NaBH4 showed excellent activity in the chemoselective reduction of a variety of carboxylic esters to their corresponding alcohols in good to excellent yields under mild conditions. Georg Thieme Verlag Stuttgart.
- Jagdale, Arun R.,Paraskar, Abhimanyu S.,Sudalai, Arumugam
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experimental part
p. 660 - 664
(2009/07/03)
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- COMPOUNDS
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A compound of formula (I): compositions and medicaments containing the same as well as processes for the preparation and use of such compounds, compositions and medicaments, particularly in diseases associated with inappropriate Aurora activity.
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Page/Page column 63
(2010/11/26)
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- BIFUNCTIONAL HETEROCYCLIC COMPOUNDS AND METHODS OF MAKING AND USING SAME
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The invention provides a family of bifunctional heterocyclic compounds useful as anti-infective, anti-proliferative, anti-inflammatory, and prokinetic agents. The invention also provides methods of making the bifunctional hetercyclic compounds, and methods of using such compounds as anti-infective, anti-proliferative agents, anti-inflammatory, and/or prokinetic agents.
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Page/Page column 302
(2010/02/06)
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- CHEMISTRY OF NITRO ETHERS. XVIII. SIMPLIFIED SYNTHESIS OF 2-(4-NITROPHENYL)ETHANOL
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A method was developed for the preparative synthesis of 2-(4-nitrophenyl)ethanol by the nitration of 2-phenylethanol followed by acid hydrolysis of 2-(4-nitrophenyl)ethyl nitrate.
- Kochergin, P. M.,Blinova, L. S.
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p. 1556 - 1558
(2007/10/03)
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- Nucleosides. Part LVI. Aminolysis of carbamates of adenosine and cytidine
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The 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) group, introduced 1984 as protecting group for exocyclic amino functions of nucleic-acid bases, reacts with amines under mild conditions to urea derivatives. Treatment of 2',5'-di-O-acetyl-N6-[2-(4-nitrophenyl)ethoxycarbonyl]cordycepin (3) with NH3/MeOH overnight at room temperature affords cordycepin (4) and N6-carbamoylcordycepin (5). Preliminary investigations towards the elucidation of the reaction mechanism indicate that the aminolysis proceeds via an addition-elimination or an isocyanate mechanism, depending on the reaction conditions. The phenoxycarbonyl (phoc) group at N6 or N4 was chosen to study the mild conversion of carbamates with aromatic amines into ureas of adenosine and cytidine, respectively.
- Sigmund,Pfleiderer
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p. 1267 - 1280
(2007/10/02)
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- Biosynthesis of the Antibiotic Obafluorin from p-Aminophenylalanine and Glycine (Glyoxylate)
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Results of experiments using 'resting' cells of Pseudomonas fluorescens with -, - and 2H2>-glycine as precursors show that glyoxylic acid is specifically the source of C-1 and C-2 of the antibiotic obafluorin 1.The 13C labelling patterns are consistent with the passage of the precursors through the tartronic semialdehyde and glyoxylate pathways.The glycine derivative 6 is not a precursor for 1.The analogues 24 and 25 of p-aminophenylalanine 3 are synthesised and tested as substrates for biosynthesis in P. fluorescens.With 24, the metabolite 26 is detected; no metabolites of 25 are detected.
- Herbert, Richard B.,Knaggs, Andrew R.
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p. 109 - 114
(2007/10/02)
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- Photochemistry of Nucleoside Transport Inhibitor 6-S-Benzylated Thiopurine Ribonucleosides. Implications for a New Class of Photoaffinity Labels
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Photochemistry of the nucleoside transport inhibitor 6--9-(β-D-ribofuranosyl)purine (NBMPR, 1) yielded products from the initial homolytic cleavage of the benzyl-sulfur bond.Photoreduction of the nitro group also occurred to a minor e
- Fleming, Steven A.,Rawlins, David B.,Samano, Vicente,Robins, Morris J.
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p. 5968 - 5976
(2007/10/02)
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- Chemical compounds
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A novel class of protecting compounds, particularly for amino acids, is based on 2,2 di nitrophenyl ethan- groups, particularly the groups wherein the nitro is in the para position. The ethyl group may be substituted, e.g. by an alkyl group, in the l- position. Preferred compounds include the alcohol or halide which are suitable for protecting acid functional groups, and esters, including activated and substituted esters, particularly the succinimidyl ester, for protecting amine groups. The invention includes methods of manufacture and use, together with protected amino acids.
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- DNA-directed alkylating agents. 2. Synthesis and biological activity of platinum complexes linked to 9-anilinoacridine
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Two different classes of cis-diaminedichloroplatinum(II) complexes linked to the DNA-intercalating chromophore 9-anilinoacridine have been synthesized and evaluated as DNA-targeted antitumor agents. Two different Pt chelating ligands were investigated (based on 1,2-ethanediamine and 1,3-propanediamine), designed to deliver the Pt in an orientation likely to respectively enhance either intrastrand or interstrand cross-linking. Although both sets of ligands were somewhat unstable under neutral or basic conditions with respect to disproportionation, the corresponding Pt complexes, once prepared, appeared to be quite stable. All the Pt complexes were monitored for purity by TLC, HPLC, and FAB mass spectra, and the mode of Pt coordination was established by 195Pt NMR spectroscopy. The complexes appeared to cause simultaneous platination and intercalative unwinding of plasmid DNA. In vitro studies were carried out with both wild-type and cisplatin-resistant P388 cell lines. Whereas cisplatin itself and the ethylenediamine and 1,3-propanediamine complexes used as standards were about 10-fold less active against the resistant line, the ethylenediamine-linked Pt complexes showed no differential toxicity between the two lines and the propanediamine-linked complexes showed significant differentials (up to 8-fold) in favor of the cisplatin-resistant line. However, these were no greater than those shown by the unplatinated ligands themselves. The majority of the acridine complexes were inactive in vivo against the wild-type P388 leukemia. They were very insoluble, and although a suitable formulation was found, this may have been a factor. It is also possible that these compounds bind in such a way as to direct the Pt away from the major groove.
- Palmer,Lee,Johnson,Baguley,Wickham,Wakelin,McFadyen,Denny
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p. 3008 - 3014
(2007/10/02)
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- Sructure an Mechanism in the Photo-Retro-Aldol Type Reactions of Nitrobenzyl Derivatives. Photochemical Heterolytic Cleavage of C-C Bonds
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The photo-retro-aldol type reactions of several nitroaromatic compounds have been studied in aqueous solution over the pH 1-14 range.These reactions are observed only in aqueous or in predominantly aqueous solution.Catalysis of reaction due to hydroxide ion is observed for several derivatives.Quantum yields of reaction and product ratios (of nitrotoluene vs dinitrobibenzyl) are reported as a function of pH.The proposed mechanism of reaction involves heterolytic cleavage of the benzylic C-C bond from the triplet excited state in the primary photochemical step to generate a nitrobenzyl carbanion and a carbocation-equivalent fragment, except for the nitrophenylacetates 24-26, which eliminate CO2 in place of such a fragment.Photogenerated nitrobenzyl carbanions are efficiently trapped by molecular oxygen to give isolable hydroperoxides at pH 9 M-1 s-1.The results show that photochemical C-C bond heterolysis requires favorable stabilization of both the carbanion and carbocation-derived fragments.Hydroxide ion catalysis may also facilitate the process.The use of the nitrobenzyl moiety as the carbanion-stabilizing group appears to be generally applicable, as demonstrated by the systems studied.
- Wan, Peter,Muralidharan, S.
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p. 4336 - 4345
(2007/10/02)
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- CONVENIENT METHOD FOR THE CHEMOSELECTIVE AND REGIOSELECTIVE REDUCTION OF OXIRANES WITH SODIUM BOROHYDRIDE IN SINGLE SOLVENT
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Chemo- and regio-selective reduction of oxiranes to the corresponding alcohol are performed in high yields with sodium borohydride in single solvent (ethanol or 2-propanol).
- Ookawa, Atsuhiro,Kitade, Masaya,Soai, Kenso
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p. 213 - 216
(2007/10/02)
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- Electrogenerated Base (EG Base) Induced Hydroxymethylation of the Side Chain of Nitroalkylbenzenes with Paraformaldehyde
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Hydroxymethylation of nitroalkylbenzenes with paraformaldehyde was accomplished by electrolysis in a (CH2O)n-DMF-Et4NOTs-(Pt electrode) system.The reaction was found to be catalytic (0.25 faraday/mol) and dependent on the electroreduction of formaldehyde and/or nitroalkylbenzene.A variety of nitroalkylbenzenes were transformed to their corresponding mono- and/or bishydroxymethylated derivatives in good yield.The product yield and selectivity were shown to depend on the order of reagent addition, solvent, supporting electrolyte, and structure of the starting nitroalkylbenzenes.A plausible mechanism of the generation of base catalysts (EG base) in electroreductive media is discussed.
- Torii, Sigeru,Murakami, Yasuo,Tanaka, Hideo,Okamoto, Koichi
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p. 3143 - 3147
(2007/10/02)
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- Antibacterial Benzisoxazolones. An Unusual Rearrangement Product from o-Nitrostyrene Oxide en Route to the Photolabile Carbonyl Protecting Group (o-Nitrophenyl)ethylene Glycol
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In the process of synthesizing the known, photolabile protecting group (o-nitrophenyl)ethylene glycol, we uncovered an acid-mediated rearrangement of o-nitrostyrene oxide to 1-(hydroxymethyl)-2,1-benzisoxazol-3(1H)-one.The structure was ascertained by IR, UV, 1H NMR, 13C NMR, MS, and X-ray crystallography.Also the benzisoxazolone was prepared by independent synthesis from an o-nitrobenzoate.Another novel transformation uncovered was the conversion of o-nitrostyrene oxide to 2-(o-nitrophenyl)ethanol with use of potassium hydroxide and 18-crown-6.Similiar chemistry was insignificant with p-nitrostyrene oxide.The benzisoxazolone exhibited antibacterial and antileukemic activity (in vitro).
- Wierenga, Wendell,Harrison, Allen W.,Evans, Bruce R.,Chidester, Connie G.
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p. 438 - 442
(2007/10/02)
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- Nucleotide. XIV. Substituierte β-Phenylaethyl-Gruppen. Neue Schutzgruppen fuer Oligonucleotid-Synthesen nach dem Phosphorsaeuretriester-Verfahren
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Various o- and p-substituted β-phenylethanols (2-10) have been synthesized and investigated as blocking groups in the phosphotriester approach.A large number of 5'-O-tritylated thymidine-3'-phosphotriesters (13-36) with two different phosphate protecting groups have been prepared, characterized, and studied according to their chemical stability and usefullness for oligonucleotide syntheses.The combination of a 5'-O-monomethoxytrityl- and a 3'-(2,5-dichlorophenyl, p-nitrophenylethyl)-phosphate function as in 18 turned out to possess optimal properties as a monomeric nucleotide building block due to the fact that these blocking groups can be quantitatively and selectively be removed without harming each other by trifluoroacetic acid in chloroform to 41, by oximate to 42, and by DBU to 43.The base-catalyzed removal of the monosubstituted phenylethyl groups by DBU or DBN respectively as well as the disubstituted phenylethyl groups by triethylamine in aprotic solvents is a β-elimination process leading to phosphodiesters without attack on the P-center.
- Uhlmann, Eugen,Pfleiderer, Wolfgang
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p. 1688 - 1703
(2007/10/02)
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