- Optical resolution by preferential crystallization of (RS)-α-amino-γ-butyrolactone hydrochloride
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(RS)-α-Amino-γ-butyrolactone hydrochloride [(RS)-ABL·HCl] was found to exist as a conglomerate based on the infrared spectrum, solubility, and melting point. Optical resolution by preferential crystallization of (RS)-ABL·HCl was achieved to yield (R)- and (S)-ABL·HCl. The obtained (R)- and (S)-ABL·HCl were recrystallized, taking into account the solubility of (RS)-ABL·HCl to give optically pure (R)- and (S)-ABL·HCl.
- Shiraiwa, Tadashi,Miyazaki, Hideya,Ohta, Atsushi,Waki, Yukitaka,Yasuda, Masahiro,Morishita, Toshimitsu,Kurokawa, Hidemoto
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Read Online
- A cogeneration process for producing sulfur and sulfur on behalf of acetate acid diester method (by machine translation)
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The invention technical field of chemical synthesis, in particular relates to a methionine as raw material production process for producing sulfur and sulfur on behalf of acetate acid diester method. The invention states the payment proportional to production for preparing sulfur and sulfur on behalf of acetate acid diester method, in order to methionine and halogenated acetic acid as the raw material, the preparation comprising a homoserine lactone hydrohalide salt (IV), a sulfur acetate (I) and sulfur on behalf of the b b acid diester (II) of the three kinds of chemical products, and each between the products easy to separate and purify. (by machine translation)
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Paragraph 0086; 0088
(2018/12/02)
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- Preparation method of high-optical-purity D- or L-selenomethionine
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The invention discloses a preparation method of high-optical-purity D- or L-selenomethionine. The preparation method comprises the following steps: by taking D- or L-methionine as initial raw materials and diethyl sulfate or halogenated alkyl acid or derived esters as alkylation reagents, generating sulfonium salt, desulfurizing and closing ring under acidic conditions, to produce alpha-amino-gama-butyrolactone halate, having addition reaction to alpha-amino-gama-butyrolactone halate with methyl selenol salt and opening ring, acidifying with organic acid, and recrystallizing to obtain D- or L-selenomethionine. The chemical purity of the product is more than or equal to 99%, and the high optical purity is more than or equal to 99%. The preparation method is low-cost and easily available in raw materials, simple in steps and easy to operate, simple in reaction conditions, and suitable for large-scale production.
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Paragraph 0031; 0032
(2017/08/30)
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- Chemo-enzymatic synthesis of the azasugars 1,4-dideoxyallonojirimycin and 1,4-dideoxymannojirimycin
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The enzymatic resolution of the N-phenylacetyl derivative of racemic homoserine lactone with penicillin G acylase immobilized on Eupergit C gave (R)-(+)-α-amino-γ-butyrolactone and (S)-(-)-α-N- phenylacetamido-γ-butyrolactone in high enantiomeric purity (ee >99%) and 46-47% yields for each enantiomer. The enantiomers were converted into azasugars 1,4-dideoxyallonojirimycin and 1,4-dideoxymannojirimycin using Wittig olefination, catalytic ring-closing metathesis (RCM), and stereoselective dihydroxylation with OsO4 in 29% overall yield over 11 high yielding steps. Enzyme inhibition studies showed that 1,4-dideoxyallonojirimycin is a better β-glucosidase inhibitor (IC50 32.4 μM toward β-glucosidase from almonds) and a better β-galactosidase inhibitor (IC50 5.9 mM for β-galactosidase from Aspergillus oryzae) than 1,4-dideoxymannojirimycin (IC50 2.86 mM and 12.5 mM for β-glucosidase and β-galactosidase, respectively).
- Venkataiah, Mallam,Reddipalli, Gowrisankar,Jasti, Lakshmi Swarnalatha,Fadnavis, Nitin W.
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experimental part
p. 1855 - 1860
(2012/01/13)
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- A new stereocontrolled approach to a key intermediate in the synthesis of (25,3R)-capreomycidine
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A new stereocontrolled approach to the synthesis of advanced intermediate in the synthesis of nonproteinogenic amino acid (2S,3R)-capreomycidine via the novel domino reaction has been developed.
- Martinkova, Miroslava,Gonda, Jozef,Dzoganova, Martina
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p. 1199 - 1210
(2008/03/27)
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- Asymmetric Synthesis of α-Amino Acids via Cationic Aza-Cope Rearrengements
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Ene-iminium intermediates resulting from reaction between glyoxal and β-amino alcohols rearrange by an aza-Cope process.Three different tandem reactions are thus carried out; their first component is this cationic rearrangement, the second step being either an iminium hydrolysis, a nucleophile-induced ene-iminium cyclization or a Mannich reaction.The last two sequences lead to homochiral proline derivatives.
- Agami, Claude,Couty, Francois,Lin, Jing,Mikaeloff, Axelle,Poursoulis, Michel
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p. 7239 - 7250
(2007/10/02)
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- Asymmetric Syntheses via Heterocyclic Intermediates; XXVII. Enantioselective Synthesis of (R)-Homoserine Methyl Esters and (R)-α-Methyl-homoserine Methyl Esters and of the Corresponding α-Amino-γ-lactones by the Bis-lactim Ether Method
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An asymmetric synthesis of various (R)-homoserine methyl esters and (R)-α-methylhomoserine methyl esters starting from the bis-lactim ethers of cyclo-(L-Val-Gly) and cyclo-(L-Val-Ala) and oxiranes is described
- Gull, Reinhold,Schoellkopf, Ulrich
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p. 1052 - 1055
(2007/10/02)
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