An Efficient Method for the Chemoselective Preparation of Benzoylated 1,2-Diols from Epoxides

Khalafi-Nezhad, Ali; Rad, Mohammad Navid Soltani; Khoshnood, Abbas

doi:10.1055/s-2003-42416

Cited by 33 publications

(16 citation statements)

References 6 publications

(9 reference statements)

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“…Nevertheless, there are some reports of comparable reactions with epoxide moieties and carboxylic acids, which took place under metal-mediated catalysis. The reported catalysts for the ring-opening reactions of epoxides initiated by carboxylic acids are generally limited to Lewis acid catalysts, such as FeCl 3 , tetrabutylammonium chloride and bromide, and Ce(OTf) 4 [18][19][20][21]. In the case of glycidol, the combination of the high ring strain of the epoxide and the polarity of the carbon-oxygen bonds makes the ring prone to nucleophilic attack.…”

Section: Modification Of Hpes 1 To Uniform Diol Endgroupsmentioning

confidence: 99%

Polyester-Based, Biodegradable Core-Multishell Nanocarriers for the Transport of Hydrophobic Drugs

2016

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A water-soluble, core-multishell (CMS) nanocarrier based on a new hyperbranched polyester core building block was synthesized and characterized towards drug transport and degradation of the nanocarrier. The hydrophobic drug dexamethasone was encapsulated and the enzyme-mediated biodegradability was investigated by NMR spectroscopy. The new CMS nanocarrier can transport one molecule of dexamethasone and degrades within five days at a skin temperature of 32˝C to biocompatible fragments.

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Section: Modification Of Hpes 1 To Uniform Diol Endgroupsmentioning

confidence: 99%

Polyester-Based, Biodegradable Core-Multishell Nanocarriers for the Transport of Hydrophobic Drugs

2016

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“…5 In contrast to the chemo-and region-selective ring opening of terminal epoxides with carboxylic acids, there are few reports on the asymmetric ring opening (ARO) of racemic epoxides using carboxylic acid as a nucleophile. [5][6][7][8][9] A previous study showed that chiral cobalt-salen complexes displayed good reactivity and high enantioselectivity for monoester synthesis via the EKR reaction. 10 Because chiral cobalt-salen complexes are very active and enantioselective catalysts in ARO reactions, 11 they are excellent candidates for the covalent attachment of homogeneous ligands to polymeric or inorganic supports.…”

Section: Introductionmentioning

confidence: 99%

Superior Effect of Ultrasonic Homogenization to Mechanical Agitation on Accelerating Reaction Rates in Asymmetric Ring Opening of Epoxides

Lee

Park

et al. 2017

Bulletin Korean Chem Soc

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Double‐layered mesoporous silica was prepared for use as an efficient support for the encapsulation of chiral salen Co‐BF3 complexes in the pore channels. The heterogenized chiral salen complex was applied successfully to the asymmetric ring opening (ARO) of terminal epoxides using water, alcohols, and carboxylic acids as nucleophiles. Although the homogeneous salen catalyst exhibited higher catalytic activity than the heterogenized catalyst in ARO reactions as expected, the heterogeneous salen catalysts exhibited high catalytic activities that were sufficient for practical applications. This study evaluated the unique contribution of ultrasonic irradiation as a powerful mixing medium to improve the kinetics in comparison to conventional mechanical agitation during the ARO reactions. Both the homogeneous and heterogeneous chiral salen complexes catalyzed enantioselectively the racemic or chiral epoxides under ultrasonication. The adoption of ultrasonic irradiation in the catalysis resulted in a superior mixing effect to vigorous mechanical stirring. The reaction time was shortened to obtain the highest enantiomeric excess (%ee) when ultrasonic irradiation was applied to the reaction system. Through the ARO reaction of epoxide by phenol derivatives, the highly enantio‐enriched β‐blockers could be synthesized easily from racemic terminal epoxides or chiral ones using chiral cobalt–salen catalysts. The regioselective ARO reaction of (R)‐ECH with propionic or butyric acid proceeded smoothly at room temperature under ultrasonic exposure in the presence of the heterogenized catalyst. The corresponding glycidyl alkylates were produced with excellent optical purity of up to 98%ee. The chiral cobalt–salen complexes encapsulated in MCM‐41 retained its catalytic activity and enantioselectivity for three recycles. Consequently, the heterogeneous chiral catalysts anchored in MCM‐41 offered the practical advantages of facile reuse through simple recovery from the reactant and products.

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“…1, CH 1, CH 2, and CH 3 have photochemically active C=C double bonds those are cross-linkable by irradiation of radical initiators [9][10][11][12]. In those polymers, reactive methacrylate side chains have various side chain lengths, and also various densities in the main chains (ratios of x and y were set to 1:1, 4:1, or 10:1).…”

Section: Introductionmentioning

confidence: 99%

Effect of Alkyl Group on the Photocrosslinking of Alkyl Methacrylate Based Copolymers

Karatsu

Narusawa

Yagai

et al. 2013

J. Photopol. Sci. Technol.

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Three series of alkyl methacrylate based copolymers having photo-reactive side chains (C=C double bond) were synthesized and examined their performances as photopolymer in the presence of suitable oxime ester or triazine type radical photo-initiators for 365 nm light. Along to our previous report showed that correlation was observed between photochemical reactivity and chain length of the side chain/density of reactive side chain in the cyclohexyl methacrylate main chain. Our proposed mechanism is that sterically stacked nonpolar cyclohexyl groups may push out the polar reactive side chains, and length and density of the side chain controls cross linking between two reactive sites in the single main chain or two different main chains. Now we have examined structural effect of the alkyl groups on the efficiency of photocrosslinking. We have examined 5 series and totally 15 polymers. As a result, cyclohexyl methacrylate based copolymer showed excellent performance for polymerization.

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An Efficient Method for the Chemoselective Preparation of Benzoylated 1,2-Diols from Epoxides

Cited by 33 publications

References 6 publications

Polyester-Based, Biodegradable Core-Multishell Nanocarriers for the Transport of Hydrophobic Drugs

Polyester-Based, Biodegradable Core-Multishell Nanocarriers for the Transport of Hydrophobic Drugs

Superior Effect of Ultrasonic Homogenization to Mechanical Agitation on Accelerating Reaction Rates in Asymmetric Ring Opening of Epoxides

Effect of Alkyl Group on the Photocrosslinking of Alkyl Methacrylate Based Copolymers

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