Patent
Process for preparing ACHPA
Paul F. Schuda,William J. Greenlee,Philip Escola,Prasun K. Chakravarty +3 more
- 27 Jul 1988
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TL;DR: In this article, an improved process for preparing (3S,4S)-N-.alpha.-BOC)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid ethyl ester was presented.
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Abstract: TITLE OF THE INVENTION: IMPROVED PROCESS FOR PREPARING ACHPA ABSTRACT OF THE DISCLOSURE A process for preparing (3S,4S)-N-.alpha.-BOC)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid ethyl ester comprising (a) reacting the N-.alpha.-BOC-amino-3-hexahydrophenyl propionic acid with 1,1-carbonyldiimidazole, to form an acylimidazol-activated derivative of said acid; (b) coupling said acylimidazole-activated derivative with the magnesium salt of malonic acid monoethylester to afford the .beta.-ketoester; (c) reducing said .beta.-ketoester using sodium cyanoborohydride in tetrahydrofuran and glacial acetic acid to produce a mixture of (3S,4S)-(N.alpha.-BOC)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid ethyl ester and (3B,4S)-(N.alpha.-BOC)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid ethyl ester; (d) crystallizing off the (3R,4S) compound and purifying the remaining product to afford optically-pure (3S,4S)-(N.alpha.-BOC)-4-amino-5-cyclohexyl-3-hydroxypentanoic acid.
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Citations
Patent
Process for the hydrogenation of aromatic compounds
Hartung Rolf,Franz Hitzel-Zerrahn,Thomas Dr. Müller,Jörg Dr. Pietsch +3 more
- 19 Jun 2004
TL;DR: In this paper, a process for the hydrogenation of aromatic or heteroaromatic compounds and in particular on the ring hydrogenation for compounds having the formula (I) was presented.
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References
Patent
Process for the production of carnitine
Leander Tenud
- 25 Sep 1975
TL;DR: The process for the production of carnitine hydrochloride which involves reacting an ester of γ-halo-acetoacetic acid having the formula: ##STR1## R1 is a hydrogen, R2 is a lower alkyl group having 1 to 10 carbon atoms and X is halogen selected from the group consisting of chlorine or bromine, with an alkali alcoholate, which is present in a stoichiometrically excessive amount, at a temperature between 0° and -40° C as discussed by the authors.
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Patent
Process for the preparation of chiral 3-amino-2-hydroxypropionic acid and N-blocked derivatives thereof
Tattanahalli L. Nagabhushan,Alan B. Cooper +1 more
- 06 Jun 1979
TL;DR: In this article, the authors described a novel process whereby D-glucose and D-mannose are converted to S-3-amino-2-hydroxypropionic acid and R-3amino 2-hydroxypoxypropionic acid, respectively, and their N-blocked derivatives.
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Patent
Enantioselective synthesis of 4-amino-3-hydroxy-2,4-(disubstituted)pentanoic acid
Mark G. Bock,Robert M. DiPardo +1 more
- 03 Jan 1983
TL;DR: In this article, a chiral enolate with an optically active acylating agent is synthesized enantiospecifically by acylation of the enolate and the resulting product is reduced to a protected form of the desired product.
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Patent
Separation of diastereomers
James Stanley Kaltenbronn,Michael Stier +1 more
- 15 Sep 1987
TL;DR: The S,S-isomers of Boc-benztine and Boccyclotine can be produced via the fractional crystallization of R-(+)-alpha-methylbenzylamine salt(s) as mentioned in this paper.
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Patent
Optically pure derivates of 4-amino-3-hydroxycarboxylic acids and process for stereospecific synthesis
Jouin Patrick,D. Nisato,Bertrand Castro +2 more
- 03 Jul 1986
TL;DR: In this paper, the authors defined a process for the stereospecific preparation of optically pure (3R, 4R)-4amino-3-hydroxycarboxylic or (3S, 4S)-4-amino, 3-hydroxyl, 4-mino-, 3-mioxioxyl, and 4-acetyl-4-moxyl derivatives of the Meldrum's acid.
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