- Hydroboration of vinylglycine and allylglycine as a route to boron- derivatives of α-amino acids
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The hydroboration of protected vinylglycine and allylglycine with dicyclohexyl- or diisopinocampheylborane occurs chimio- and regioselectively with attachment of boron to the less substituted end of the carbon-carbon double bond. Homoserine or δ-hydroxynorvaline are readily obtained by H2O2/CH3CO2Na oxidation of dicyclohexylborane derivatives and 2-amino-4- boronobutanoic acid or 2-amino-5-boronopentanoic acid by reaction of diisopinocampheylborane derivatives with excess of ethanal and deprotection.
- Denniel, Valerie,Bauchat, Patrick,Danion, Daniel,Danion-Bougot, Renee
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- Synthesis of enkephalinase inhibitor
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The invention discloses a novel synthesis method of enkephalinase inhibitor Sacubitril. According to the novel synthesis method, L-Pyroglutamic acid is taken as a raw material, a plurality of steps ofreaction are carried out, and a compound I with the chirality identical to that of Sacubitril is obtained via epimerization crystallization; the compound I is subjected to acylation, and is reacted with biphenyl so as to obtain a compound II; and hydrolysis ring-opening is carried out so as to obtain a compound III; the compound III is reacted with succinic anhydride, and reduction reaction is carried out so as to obtain Sacubitril. According to the synthesis method, a novel chirality control strategy is adopted, a novel chiral center is constructed using a simple and reliable method; controlof the chiral key intermediate is carried out at the early part of the synthesis routine, so that it is beneficial for reduction of risk and cost.
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Paragraph 0017
(2018/07/10)
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- Oxidative functionalization of aliphatic and aromatic amino acid derivatives with H2O2 catalyzed by a nonheme imine based iron complex
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The oxidation of a series of N-acetyl amino acid methyl esters with H2O2 catalyzed by a very simple iminopyridine iron(ii) complex 1 easily obtainable in situ by self-assembly of 2-picolylaldehyde, 2-picolylamine, and Fe(OTf)2 was investigated. Oxidation of protected aliphatic amino acids occurs at the α-C-H bond exclusively (N-AcAlaOMe) or in competition with the side-chain functionalization (N-AcValOMe and N-AcLeuOMe). N-AcProOMe is smoothly and cleanly oxidized with high regioselectivity affording exclusively C-5 oxidation products. Remarkably, complex 1 is also able to catalyze the oxidation of the aromatic N-AcPheOMe. A marked preference for the aromatic ring hydroxylation over Cα-H and benzylic C-H oxidation was observed, leading to the clean formation of tyrosine and its phenolic isomers.
- Ticconi, Barbara,Colcerasa, Arianna,Di Stefano, Stefano,Lanzalunga, Osvaldo,Lapi, Andrea,Mazzonna, Marco,Olivo, Giorgio
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p. 19144 - 19151
(2018/05/31)
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- Oxidation of L-Proline Methyl Ester Derivatives with the Iodosylbenzene/Trimethylsilylazide Reagent Combination
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Oxidation of a series of L-Proline derivatives with the (PhIO)n/TMSN3 reagent combination is reported.Subsequent utilization of the 5-azido N-acyl functionality as a N-acyl iminium ion precursor is described.
- Magnus, Philip,Hulme, Christopher
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p. 8097 - 8100
(2007/10/02)
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- SYNTHESIS OF 2-OXA AND 2-AZA ANALOGS OF PYRROLIZIDINE-3,5-DIONES (LUKES-SORM DILACTAM)
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The synthesis of 2-oxa and 2-aza analogs of pyrrolizidine-3,5-dione (Lukes-Sorm dilactam), which has amnesia reversal activity, is reported.Optically active (+)-2-oxa and (+)-2-aza analogs and racemic 2-aza analog and its 1-methoxycarbonyl derivatives were prepared from (-)-S-pyroglutamic acid and succinimide, respectively.
- Nagasaka, Tatsuo,Hakamada, Rie,Kunii, Shin-ichi,Hamaguchi, Fumiko
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p. 619 - 630
(2007/10/02)
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- Amino Acids. 7. A Novel Synthetic Route to L-Proline
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Reaction of L-5-oxoproline esters L-2 with phosgene at 0 deg C gives L-5,5-dichloro-1-(chlorocarbonyl)proline esters L-6, which readily lose hydrogen chloride to form L-5-chloro-1-(chlorocarbonyl)-4,5-dehydroproline esters L-7.Catalytic hydrogenation (Pd/C, 180 bar) of L-7 yields L-1-(chlorocarbonyl)proline esters L-15 and thence, upon hydrolysis, L-proline (L-17).A 'one-pot reaction' for the whole sequence is described, starting from easily accessible L-5-oxoproline esters and yielding L-proline in 78percent overall yield and 99.7percent optical purity.
- Drauz, Karlheinz,Kleemann, Axel,Martens, Juergen,Scherberich, Paul,Effenberger, Franz
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p. 3494 - 3498
(2007/10/02)
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- Chemical Conversion of Cyclic α-Amino Acids to α-Aminodicarboxylic Acids by Improved Ruthenium Tetroxide Oxidation
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The ruthenium tetroxide (RuO4) oxidation of N-acylated L-proline esters, prepared from L-proline, was carried out under two-phase conditions to afford good yields of the corresponding lactams with no appreciable racemization, and the products were hydrolyzed in aqueous hydrochloric acid to L-glutamic acid.Similar transformation starting with racemic 2-piperidinecaboxylic acid and 2-azetidinecarboxylic acid gave 2-aminoadipic acid and aspartic acid, respectively.A novel chemical converion of cyclic α-amino acids into α-aminodicarboxylic acids has been accomplished.A new solvent system, ethyl acetate-water, was developed for this two-phase oxidation.It was found to be very useful in reducing the necessary reaction time.Keywords --- oxidation; regioselectivity; lactam synthesis; ruthenium tetroxide; cyclic α-amino acid; α-aminodicarboxylic acid; L-proline; L-glutamic acid; two-phase method; ethyl acetate-water system
- Yoshifuji, Shigeyuki,Tanaka, Ken-ichi,Kawai, Tomoyuki,Nitta, Yoshihiro
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p. 5515 - 5521
(2007/10/02)
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- THE FIRST CHEMICAL CONVERSION OF L-PROLINE TO L-GLUTAMIC ACID
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The ruthenium tetroxide oxidation of N-acyl-L-proline esters gave the corresponding L-pyroglutamic acid derivatives in good yields with no appreciable racemization, which lead to the first chemical conversion of L-proline to L-glutamic acid.
- Yoshifuji, Shigeyuki,Matsumoto, Hideyo,Tanaka, Ken-ichi,Nitta, Yoshihiro
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p. 2963 - 2964
(2007/10/02)
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