- Continuous Flow Preparation of Enantiomerically Pure BINOL(s) by Acylative Kinetic Resolution
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A polystyrene-immobilized isothiourea has been applied to the enantioselective acylative kinetic resolution (KR) of monoacylated BINOL(s) with inexpensive isobutyric anhydride in batch and flow. High selectivity values (s=29 at 0 °C) and a remarkable stability of the catalytic system in the operation conditions have been recorded for unsubstituted BINOL. No significant loss of activity/selectivity is recorded after 10 consecutive KR cycles in batch. A continuous flow process has been implemented and operated with a 100 mmol (32.8 g) sample of racemic monoacetylated BINOL in dichloromethane solution in an 84 hours experiment with a packed bed reactor containing 1 g (f=0.37 mmol.g?1) of the functional resin (s=17–21). Residence time can be decreased to 10 min with the same reactor to achieve a conversion of 58% with a selectivity factor s=17 when a more highly functionalized catalyst (f=0.88 mmol.g?1) is used. This translates into a remarkable combined productivity of 5.5 mmolprod ? mmolcat?1 ? h?1.
- Lai, Junshan,Neyyappadath, Rifahath M.,Pericàs, Miquel A.,Smith, Andrew D.
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supporting information
(2020/02/05)
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- Rapid Synthesis of Alkenylated BINOL Derivatives via Rh(III)-Catalyzed C-H Bond Activation
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Modification of BINOL units has been well examined via Rh-catalyzed C-H activation and functionalization reactions by using ester carbonyls as directing groups and alkenes as coupling partners. The one-pot strategy was an efficient protocol for the rapid synthesis of BINOL derivatives with retention of optical purity.
- Dong, Lin,Liu, Hao,Liu, Man,Luo, Yi,Zhang, Jing
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supporting information
(2020/06/24)
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- Base-promoted lipase-catalyzed kinetic resolution of atropisomeric 1,1′-biaryl-2,2′-diols
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Herein we report a dramatic acceleration of the lipase-catalyzed kinetic resolution of atropisomeric 1,1′-biaryl-2,2′-diols by the addition of sodium carbonate. This result likely originates from the increased nucleophilicity of the phenolic hydroxyl group toward the acyl-enzyme intermediate. Under these conditions, various substituted C2-symmetric and non-C2-symmetric binaphthols and biphenols were efficiently resolved with ~50% conversion in only 13-30 h with excellent enantioselectivity.
- Moustafa, Gamal A. I.,Kasama, Kengo,Higashio, Koichi,Akai, Shuji
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p. 1165 - 1175
(2019/01/23)
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- Arthrobacter sp. lipase catalyzed kinetic resolution of BINOL: The effect of substrate immobilization
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(S)-1,1′-Binaphthyl-2,2′-diol was prepared in high optical purity (~98%) via Arthrobacter sp. lipase (MTCC No. 5125) catalyzed kinetic resolution. The immobilization of the substrate on a solid inert support significantly improved the enantioselectivity factor (E) by almost sixfolds, i.e. from ~27 to >180. The effect of acyl substituents and co-solvents were also studied.
- Gupta, Pankaj,Rouf, Abdul,Shah, Bhahwal Ali,Mahajan, Neha,Chaubey, Asha,Taneja, Subhash Chandra
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- Efficient routes to racemic and enantiomerically pure (s)-binol diesters
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A systematic study for esterification procedures to the synthesis of BINOL diesters is described. Reaction conditions with trifluoracetic acid anhydride (TFAA) and 85% H3PO4 were selected as the best procedure to prepare enantiomeric
- Costantino, Andrea R.,Ocampo, Romina A.,Schneider, Maria G. Montiel,Fernandez, Gustavo,Koll, Liliana C.,Mandolesi, Sandra D.
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supporting information
p. 3192 - 3202
(2014/01/06)
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- Efficient acetylation of alcohols and phenols catalyzed by recyclable lithium bis(perfluoroalkylsulfonyl)imide
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An efficient acetylation of alcohols and phenols catalyzed by lithium bis(perfluoroalkylsulfonyl)-imide was developed. This acetylation features good yields, mild reaction condtions, and simple workup procedures. Furthermore, the catalyst bearing a long perfluoroalkyl chain is recoverable and readily reusable without losing any activity. Copyright
- Li, Guilong,Zhao, Gang
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p. 34 - 43,10
(2020/08/24)
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- Solution-phase synthesis and evaluation of tetraproline chiral stationary phases
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A protocol was developed for the solution-phase synthesis of multigram amounts of two 9-fluorenylmethoxycarbonyl (Fmoc)-protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution-phase-synthesized tetraproline CSPs with that prepared by stepwise solid-phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution-phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid-phase synthesis of oligoproline CSPs. Copyright
- Dai, Zhi,Ye, Guozhong,Pittman Jr., Charles U.,Li, Tingyu
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experimental part
p. 329 - 338
(2012/05/20)
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- Rational design of BINOL-based diimidazolyl ligands: Homochiral channel-like mono-component organic frameworks by hydrogen-bond-directed self-assembly
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We have developed a synthetic strategy to selectively incorporate the imidazole ring into the 1,1′-bi-2-naphthol (BINOL) skeleton at the different position. The resulting conformationally rigid BINOL-based diimidazolyl ligands bearing both hydrogen-bond-acceptors and -donators can self-assemble into homochiral channel-like mono-component organic frameworks via intermolecular O-H...N hydrogen bonds between the phenolic hydroxyl group and the N2 or N4 atom of the imidazole ring.
- Yang, Li,Yang, Fei,Lan, Jingbo,Gao, Ge,You, Jingsong,Su, Xiaoyu
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supporting information; scheme or table
p. 2618 - 2621
(2011/05/08)
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- Ultrasonic speed and related acoustical parameters of 1,1'-Binaphthalene-2, 2'-diyl diacetate solutions at 308.15 K
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The density (ρ), viscosity (η) and ultrasonic speed (U) (2MHz) of chloroform, THF, ethyl alcohol, ethyl acetate, 1,4-dioxane and 1,1'-binaphthalene-2,2'-diyl diacetate (DBNA) solutions have been determined at 308.15 K. Various acoustical parameters namely specific acoustical impedance (Z), adiabatic compressibility (ka), Van der Waals constant (b), intermolecular path length (Lf), internal pressure (π), Rao's molar sound function (R), relaxation time (τ), classical absorption coefficient (α/f2)cl and solvation number (Sn) have been derived from ρ, η and U data and correlated with concentration (C). A fairly good to excellent correlation has been observed between a particular parameter and C. Linear increase of Z, R, b, (α/f2) Cl and τ (except EA) (R2 = 0.90 - 0.999) and linear decrease of ks, π and Lf (R2 = 0.947 - 0.995) with C supported existence of powerful molecular interactions in the solutions and further supported by nonlinear increase of Sn with C. A fairly constant Gibbs free energy of activation has been observed in all the solvent systems studied.
- Adroja, Pooja P.,Gami,Patel,Parsania
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experimental part
p. 762 - 766
(2012/03/11)
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- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
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Page/Page column 45-49; 56
(2010/12/31)
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- N,N'-Diiodo-N,N'-1,2-ethanediylbis(p-toluenesulfonamide) as an efficient catalyst for acetylation of alcohols, phenols, amines, and thiols under solvent-free conditions
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N,N'-Diiodo-N,N'-1,2-ethanediylbis(p-toluenesulfonamide) (NIBTS) is a highly efficient catalyst for the acetylation of alcohols, phenols, amines, and thiols under solvent-free conditions. Primary, secondary, tertiary alcohols; phenols; amines; and thiols can be easily acetylated in good to excellent yields at 80 C. Copyright Taylor & Francis Group, LLC.
- Ghorbani-Vaghei, Ramin,Toghraei-Semiromi, Zahra
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experimental part
p. 1701 - 1707
(2010/09/17)
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- Development of new HPLC chiral stationary phases based on native and derivatized cyclofructans
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An unusual class of chiral selectors, cyclofructans, is introduced for the first time as bonded chiral stationary phases. Compared to native cyclofructans (CFs), which have rather limited capabilities as chiral selectors, aliphatic-and aromatic-functionalized CF6s possess unique and very different enantiomeric selectivities. Indeed, they are shown to separate a very broad range of racemic compounds. In particular, aliphatic-derivatized CF6s with a low substitution degree baseline separate all tested chiral primary amines. It appears that partial derivatization on the CF6 molecule disrupts the molecular internal hydrogen bonding, thereby making the core of the molecule more accessible. In contrast, highly aromaticfunctionalized CF6 stationary phases lose most of the enantioselective capabilities toward primary amines, however they gain broad selectivity for most other types of analytes. This class of stationary phases also demonstrates high "loadability" and therefore has great potential for preparative separations. The variations in enantiomeric selectivity often can be correlated with distinct structural features of the selector. The separations occur predominantly in the presence of organic solvents.
- Sun, Ping,Wang, Chunlei,Breitbach, Zachary S.,Zhang, Ying,Armstrong, Daniel W.
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experimental part
p. 10215 - 10226
(2010/05/01)
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- Convenient method for the synthesis of 6,6′-diacyl-1,1′-bi-2- naphthyl ethers
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Acylation of 1,1′-bi-2-naphthol (BINOL) ethers using Lewis acids aluminum(III) chloride and titanium(IV) chloride gave the corresponding 6,6′-diacyl derivatives in good yields. Georg Thieme Verlag Stuttgart.
- Periasamy, Mariappan,Nagaraju, Miriyala,Kishorebabu, Neela
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p. 3821 - 3826
(2008/09/17)
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- Mobile tool for HPLC reaction monitoring
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A mobile HPLC reaction monitoring tool consisting of a cart-mounted microfluidic HPLC instrument equipped with a tethered, automated sampling and dilution module is described. Several examples of the use of the instrument for carrying out reaction progress analysis are presented. Reaction aliquot size is typically only a few microliters, allowing extensive sample monitoring from small volume reactions. Reaction quenching is possible, and aliquot dilution is adjustable, with suitable precision and accuracy even at hundredfold dilution. A sampling capillary with a chemically inert stainless steel fritted terminus allows sampling from some heterogeneous reactions. The sampling interval is adjustable, from a minimum of about 4 min, upwards. Visualization of an ongoing or completed study as either stacked "waterfall" chromatograms or as graphs of integrated peak areas (or any derived function, such as percent ee or percent conversion) vs time affords the process chemist valuable information on reaction kinetics and a useful record of reaction progress over time. While online HPLC analysis has been known for some time, the compact and mobile nature of this instrument renders it especially useful for carrying out reaction progress monitoring in the laboratory environment.
- Schafer, Wes A.,Hobbs, Steve,Rehm, Jason,Rakestraw, David A.,Orella, Charles,McLaughlin, Mark,Ge, Zhihong,Welch, Christopher J.
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p. 870 - 876
(2012/12/30)
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- Lewis acid catalyzed acylation reactions: Scope and limitations
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Acylation of alcohols, thiols, and sugars were studied with a variety of Lewis acids, and it was found that Cu- and Sn(OTf)2 are very efficient in catalyzing the reaction under mild conditions. Among these two catalysts, Cu(OTf)2 was preferred because of its lower cost and relatively higher yield of the acylated product. The reaction was studied in several solvents, but CH2Cl2 was preferred. It was also observed that the present method is suitable for acylation of tertiary alcohols. Sugars were also acylated without any epimerization at the anomeric center. It is further shown here that this method is also suitable for selective acylation of primary or secondary alcohols over tertiary ones.
- Chandra, Kusum L,Saravanan,Singh, Rajesh K,Singh, Vinod K
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p. 1369 - 1374
(2007/10/03)
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- Naphthalene derivatives as fluorescent probe
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The electronic and fluorescence spectral properties of several synthesized naphthalene derivatives have been examined in acetone and in an anionic micelle. The change in fluorescence emission process of several naphthalene compounds have been compared with their parent moiety after hydroxylation, acetylation and with the increase in their skeletal rigidity. This report supplements the first hand information to choose naphthalene compounds as probe molecules in organic solvents as well as organized medium.
- Pal,Ghosh,Pal
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p. 850 - 853
(2007/10/03)
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- Indium triflate: An efficient catalyst for acylation reactions
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Indium triflate is shown to be an extremely efficient catalyst for the acylation of alcohols and amines.
- Chauhan, Kamlesh K.,Frost, Christopher G.,Love, Ian,Waite, David
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p. 1743 - 1744
(2007/10/03)
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- An efficient method for acylation reactions
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Cu(OTf)2 was found to be an efficient catalyst in the acylation reaction of alcohols, phenols, amines and thiols with acetic arthydride in CH2Cl2 or acetic acid. A catalytic cycle has been proposed for the acylation reaction.
- Saravanan, Parthasarathy,Singh, Vinod K.
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p. 2611 - 2614
(2007/10/03)
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- Zeolite HSZ-360 as a new reusable catalyst for the direct acetylation of alcohols and phenols under solventless conditions
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Alcohols and phenols were efficiently acylated with acetic anhydride without solvent over zeolite HSZ-360. The catalyst can be reused with no activity loss.
- Ballini, Roberto,Bosica, Giovanna,Carloni, Silvia,Ciaralli, Lara,Maggi, Raimondo,Sartori, Giovanni
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p. 6049 - 6052
(2007/10/03)
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- Coupling of 2,7-Dihydroxynaphthalene by Mercuric Oxide
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Oxidative phenol coupling on 2,7-dihydroxynaphthalene by HgO leads to 1,6,7,12-perylenetetrol in 60% yield.
- Pal, Anjali,Pal, Tarasankar
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p. 552 - 553
(2007/10/03)
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- Mercuration of 2-naphthol
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Mercuration of 2-naphthol in alkaline ethanol (pH~10) under refluxing condition (12 hr) afford a simple isolable compound (yield 35%). The structure of the product has been established as 1, 1′-bis(2-hydroxynaphthyl)mercury (1a) from the detailed spectral analyses of its diacetylated derivative (1b).
- Pal, Anjali,Pal, Tarasankar
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p. 157 - 160
(2007/10/03)
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- Resolution of Binaphthols and Spirobiindanols Using Cholesterol Esterase
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Cholesterol esterase (EC 3.1.1.13) catalyzes the hydrolysis of steroid, binaphthol, and spirobiindanol esters.The hydrolysis of binaphthol and spirobiindanol esters is enantiospecific and can be used to resolve these materials.Simple, synthetic-scale (200 g) procedures are detailed for the resolution of -2,2'-diol (1) and 2,2',3,3'-tetrahydro-3,3,3',3'-tetramethyl-1,1'-spirobi-6,6'-diol (6).Resolution of 1 involved hydrolysis of the dipentanoate ester catalyzed by crude, inexpensive enzyme (bovine pancreas acetone powder) and yielded each enantiomer in > 60percent of theoretical yield with >/= 99percent enantiomeric purity.Similar resolution of 6 by hydrolysis of the dihexanoate ester yielded each enantiomer in > 50percent of theoretical yield with > 95percent enentiomeric purity.These resolution involve two enzymic reactions: hydrolysis of the diester to the monoester followed by hydrolysis of the monoester to the diol.A theoretical analysis of such two-step resolutions suggests that two-step resolutions can yield products with higher enantiomeric purity than can single-step resolutions.
- Kazlauskas, Romas J.
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p. 4953 - 4959
(2007/10/02)
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- BIFUNCTIONAL CHIRAL SYNTHONS VIA BIOCHEMICAL METHODS. VII. OPTICALLY-ACTIVE 2,2'-DIHYDROXY-1,1'-BINAPHTHYL.
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Optically-active binaphthols (1R and 1S) have been prepared via microbial enantiospecific hydrolysis of axially-disymmetric (+/-)-2,2'-diacetoxy-1,1'-binaphthyl.
- Wu, Shih-Hsiung,Zhang, Li-Qing,Chen, Ching-Shih,Girdaukas, Gary,Sih, C. J.
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p. 4323 - 4326
(2007/10/02)
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