- Enantioselective Three-Step Synthesis of Homo-β-proline: A Donor-Acceptor Cyclopropane as Key Intermediate
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An enantioselective three-step synthesis of the GABA uptake inhibitor (S)-(+)-homo-β-proline was developed. The basis for the synthesis was the enantioselective CuI-catalyzed cyclopropanation of N-Boc-pyrrole, a substrate that persistently has proved to be challenging in such transformations. The cyclopropanation can be performed on a 150 mmol scale, and the two subsequent steps (i.e., hydrogenation and in situ cyclopropane-opening/double-deprotection) toward the target molecule proceed smoothly in quantitative yield without loss of enantiopurity.
- Pilsl, Ludwig K. A.,Ertl, Thomas,Reiser, Oliver
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- Piperazine ureido derivative, preparation method thereof and application of piperazine ureido derivative in medicine
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The invention relates to piperazine ureido derivatives, a preparation method thereof and an application of the piperazine ureido derivatives in medicine. In particular, the invention relates to piperazine ureido derivatives as shown in a general formula (I), a preparation method thereof, pharmaceutical compositions containing the derivatives, and uses thereof as capsid protein inhibitors, especially in prevention and/or treatment of hepatitis B, influenza, herpes, AIDS and other diseases. Wherein the definition of each group in the general formula (I) is the same as that in the specification.
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Paragraph 0238; 0240; 0241; 0242; 0243
(2021/05/12)
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- Chiral bicyclic guanidine as a versatile bronsted base catalyst for the enantioselective michael reactions of dithiomalonates and β-keto thioesters
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A chiral bicyclic guanidine was developed as a versatile Bronsted base catalyst for the enantioselective Michael reactions of dithiomalonates and β-keto thioesters using a range of acceptors including maleimides, cyclic enones, furanone and acyclic 1,4-di
- Ye, Weiping,Jiang, Zhiyong,Zhao, Yujun,Goh, Serena Li Min,Leow, Dasheng,Soh, Ying-Teck,Tan, Choon-Hong
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p. 2454 - 2458
(2008/09/19)
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- A convenient chemoenzymatic synthesis of (R)-(-) and (S)-(+)-homo-β- proline
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Both enantiomers of the heterocyclic GABA analogue homo-β-proline (3-pyrrolidineacetic acid) were synthesized by a chemoenzymatic method involving the use of two enantiocomplementary enzymes in the disymmetric hydrolyses of 3-nitromethylglutaric acid diethyl ester.
- Felluga, Fulvia,Gombac, Valentina,Pitacco, Giuliana,Valentin, Ennio
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p. 3323 - 3327
(2007/10/03)
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- Conformationally constrained no synthase inhibitors: Rigid analogs of L- N-iminoethylornithine
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The synthesis of eight rigid analogs of L-N-iminoethylomithine (L-NIO) is described. The compounds have been evaluated for their inhibition of inducible nitric oxide synthase. Preliminary structure-activity relationships are discussed.
- Eustache, Jacques,Grob, Alfred,Lam, Charles,Sellier, Odile,Schulz, Gerhard
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p. 2961 - 2966
(2007/10/03)
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- A practical ex-chiral-pool synthesis of β-proline and homo-β-proline
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Starting from aspartic acid an efficient synthesis of enantiomerically pure β-proline and homo-β-proline is described. The key step of the synthesis includes formation of the 1,4-biselectrophile 6, followed by rearrangement via the aziridinium intermediate 7 and ring closure to give the pyrrolidinium salt 9a which can serve as a common precursor for both target compounds.
- Thomas, Christoph,Orecher, Florian,Gmeiner, Peter
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p. 1491 - 1496
(2007/10/03)
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- Diastereomerically pure pyrrolidin-2-ones by intramolecular Michael reaction. Synthesis of both (S)- and (R)-3-pyrrolidineacetic acid
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By intramolecular conjugate addition of their derived enolates, the amides 5 and 6 gave diastereomeric mixtures of pyrrolidin-2-ones 10,11 and 12,13, in good yield and 80:20 d.r. After chromatographic separation, the configuration of pure diastereomers wa
- Galeazzi, Roberta,Geremia, Silvano,Mobbili, Giovanna,Orena, Mario
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- A convenient approach to diastereomerically pure 1,3,4-trisubstituted pyrrolidin-2-ones by intramolecular cyclisation of N-(2-alken-1-yl)amides mediated by Mn(III). An entry to both (R)- and (S)-3-pyrrolidineacetic acid
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The oxidative cyclisation of a series of either (S)-N-(2-alken-1-yl)-N-(1-phenyleth-1-yl)-acetoacetamides 5a-d and methoxycarbonylacetamides 6a-b, performed by using Mn(OAc)3 · 2H2O and Cu(OAc)2 · H2O in acetic
- Galeazzi, Roberta,Mobbili, Giovanna,Orena, Mario
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p. 1069 - 1084
(2007/10/03)
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- GABA Agonists and Uptake Inhibitors. Synthesis, Absolute Stereochemistry, and Enantioselectivity of (R)-(-)- and (S)-(+)-Homo-β-proline
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The cyclic analogue of 4-aminobutyric acid (GABA), 3-pyrrolidineacetic acid (homo-β-proline), is a potent agonist at GABAA receptors, it interacts effectively with GABA-uptake mechanisms, and it is a moderately potent inhibitor of GABAB/s
- Nielsen, Lone,Brehm, Lotte,Krogsgaard-Larsen, Povl
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