- ASYMMETRIC CYCLOPROPANATION OF FUMARATES WITH METHYLENE BROMIDE CATALYZED BY COBALT OR NICKEL COMPLEXES
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Highly optically active trans-1,2-cyclopropanedicarboxylic acid derivatives were prepared from chiral fumarates and methylene bromide catalyzed by cobalt(0) or nickel(0) complexes.
- Matsuda, Hideki,Kanai, Hiroyoshi
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- Enantioselective bacterial hydrolysis of amido esters and diamides derived from (±)-trans-cyclopropane-1,2-dicarboxylic acid
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Different optically active amido esters, mixed acid esters, amido acids, and diamides derived from trans-cyclopropane-1,2-dicarboxylic acid were prepared from the commercially available diethyl (±)-trans-cyclopropane-1,2- dicarboxylate. The key step was the Rhodococcus rhodochrous IFO 15564 catalyzed hydrolysis of the corresponding racemic amide. The amidase present in this microorganism showed moderate to high enantioselectivity towards these substrates. In addition a simple and efficient Curtius rearrangement of some of the enzymatically prepared cyclopropanecarboxylic acids allowed us to obtain optically active β-aminocyclopropanecarboxylic acid derivatives with high yields and enantiomeric excesses. The Royal Society of Chemistry.
- Hugentobler, Katharina G.,Rebolledo, Francisca
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p. 615 - 623
(2014/01/06)
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- COSMETIC USES AND METHODS FOR INDOLINE GRANZYME B INHIBITOR COMPOSITIONS
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Cosmetic uses and methods for indoline granzyme B inhibitor compounds in compositions with a cosmetically acceptable carrier. Uses and methods for treating, reducing or inhibiting the appearance of ageing in the skin are provided. Also provided are compositions and formulation for cosmetic uses and methods of maintaining a youthful appearance, reducing an appearance of ageing, inhibiting an appearance of ageing, reducing a rate of an appearance of ageing, reducing a skin inelasticity, reducing a rate of increasing skin inelasticity, maintaining a skin elasticity, and increasing the density of hair follicles of a skin of a subjecl. The uses and methods comprise applying/administering an indoline granzyme B inhibitor to a skin, or a portion of a skin of the subject.
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Page/Page column 100
(2014/10/15)
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- Cyclopropane PNA: Observable triplex melting in a PNA constrained with a 3-membered ring
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The first peptide nucleic acid (PNA) with a cyclopropane in the backbone has been synthesized, and the effects of the ring on DNA/RNA binding properties of the PNA have been examined. Well-defined triplex to duplex melting transitions of PNA2 DNA complexes is clearly observed by variable temperature UV absorbance with the cyclopropane-constrained PNA.
- Pokorski, Jonathan K.,Myers, Michael C.,Appella, Daniel H.
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p. 915 - 917
(2007/10/03)
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- Halothenoyl-cyclopropane-1-carboxylic acid derivatives
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Compounds of formula (I) wherein R is hydroxy, linear or branched C1-C6 alkoxy, phenoxy, benzyloxy, a group -N(R1R2) wherein R1 is hydrogen, linear or branched C1-C4 alkyl, benzy
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- Glycoside derivatives of 2-(3,4-dichlorobenzoyl)-cycopropane-1-carboxylic acid
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The compounds of formula I: ???wherein R is a glycoside residue optionally having one or more hydroxy groups alkylated or acylated by C1-C4 alkyl or acyl groups, are long lasting inhibitors of kynurenine 3-monooxygenase (KMO) and potent glutamate (GLU) re
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- Highly Enantioselective Intermolecular Cyclopropanation Catalyzed by Dirhodium(II) Tetrakis[3(S)-phthalimido-2-piperidinonate]: Solvent Dependency of the Enantioselection
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The enantioselectivity in cyclopropanations catalyzed by dirhodium(II) tetrakis[3(S)-phthalimido-2-piperidinonate] has been found to be substantially improved by employing ether as the rarely used solvent. Cyclopropanations of styrenes or 1,1-disubstituted alkenes with 2,4-dimethyl-3-pentyl diazoacetate in ether are promoted by this catalyst to afford the corresponding cyclopropane products in the highest levels of enantioselectivity (up to 98% ee) reported to date for the dirhodium(II)-catalyzed intermolecular cyclopropanation reactions.
- Kitagaki, Shinji,Matsuda, Hideo,Watanabe, Nobuhide,Hashimoto, Shun-Ichi
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p. 1171 - 1174
(2007/10/03)
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- Enzymes in Organic Synthesis. 39. Preparations of Chiral Cyclic Acid-Esters and Bicyclic Lactones via Stereoselective Pig Liver Esterase Catalyzed Hydrolyses of Cyclic Meso Diesters
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Pig liver esterase catalyzed hydrolyses of meso-dimethyl cyclopropane-, cyclobutane-, and cyclohexane-1,2-dicarboxylates are enantiotopically specific, giving acid-ester products that are readily converted into γ-lactones of > 97percent ee that are of value as chiral synthons.There is a dramatic change of stereospecificity on going from the cyclopropane and cyclobutane diesters to the cyclohexane substrate, with the cyclopentane diester hydrolysis representing the changeover point within the series.This reversal of enzyme stereospecificity is explicable in terms of a twobinding-pocket active-site model.Hydrolyses of dimethyl oxirane-2,3-dicarboxylate and of cyclopropane-1,2-diacetates are also stereoselective, giving product ee's up to 30-70percent.
- Sabbioni, Gabriele,Jones, J. Bryan
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p. 4565 - 4570
(2007/10/02)
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- Stereoselective Synthesis of Optically Active Dictyopterenes A and B and Their Geometrical Isomers
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Optically active dictyopterenes A and B and their geometrical isomers were stereoselectively synthesized by condensation of acrolein with carboethoxymethyl dimethylsulfonium bromide and by the Wittig reaction between (+)-2-vinylcyclopropylcarbaldehyde, which was derived from partially resolved (+)-(1S,2R)-2-vinylcyclopropanecarboxylic acid, and phosphonium salts in liquid-solid two-phase systems using crown ethers.
- Kajiwara, Tadahiko,Nakatomi, Toshihiro,Sasaki, Yasushi,Hatanaka, Akikazu
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p. 2099 - 2104
(2007/10/02)
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