- Stereoselective synthesis of protected amino alkyl epoxides
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The mechanism of epoxidation of chiral allyl amines has been investigated. The intrinsic stereoselectivity for epoxidation is shown to be approximately 5:1 and is independent of the nitrogen substituent. However, the nature of the N-protecting group influences the stability of the undesired epoxide to the acidic media, with the minor diastereomer undergoing preferential decomposition. Conditions are reported for the highly stereoselective synthesis of epoxide 9R, an important building block in the synthesis of several enzyme inhibitors.
- Romeo, Sergio,Rich, Daniel H.
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- Thionyl Chloride-Mediated Synthesis of tert-Butyl ((S)-1-((R)-Oxiran-2-yl)-2-phenylethyl)carbamate with Boc-Involved Neighboring Group Participation
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A convenient, high-yielding preparation of tert-butyl ((S)-1-((R)-oxiran-2-yl)-2-phenylethyl)carbamate is described. An efficient chiral inversion as the key step is furnished via Boc-involved neighboring group participation mediated by thionyl chloride. This preparation has significant advantages over the previously reported methods with respect to simplicity, cost efficiency, yield, and purification procedure as well as industry reliability.
- Li, Tao,Mei, Mei,Gao, Hongjun,Li, Yuanqiang,Yan, Yongliang,Che, Daqing
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p. 1183 - 1189
(2015/03/18)
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- Facile synthetic route to (2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid and its derivatives, the key intermediates for HIV protease inhibitors
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A facile and efficient route to (2S,3S)-3-amino-2-hydroxy-4-phenylbutyric acid and its derivative (4S,5S)-4-benzyl-5-hydroxymethyl oxazolidin-2-one is presented. N-phthaloyl protected L-phenylalanine 1 was treated with thionyl chloride followed by hydroge
- Lei, Lijun,He, Xuchang,Bai, Donglu
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p. 1535 - 1540
(2007/10/03)
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- Production method of beta-amino-alpha-hydroxycarboxylic acid
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The present invention provides a production method of an optically active β-amino-α-hydroxycarboxylic acid, which includes the following steps (a)-(c): (a) treating an optically active N-carbamate protected β-amino epoxide with an acid to give an optically active 5-hydroxymethyl-2-oxazolidinone; (b) oxidizing the resulting compound in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy and hypochlorite to give an optically active 4-benzyl-2-oxo-5-oxazolidinecarboxylic acid; and (c) treating the 4-benzyl-2-oxo-5-oxazolidinecarboxylic acid with a base, and a production method of an optically active N-carbamate protected β-amino-α-hydroxycarboxylic acid which includes protection of the amino group with a carbamate type protecting group. The industrial production method of the present invention can produce these compounds efficiently.
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- Synthesis of N-BOC-3-amino-1,2-epoxy-4-phenylbutane from (3S)-hydroxy-γ-butyrolactone by means of the Hofmann rearrangement
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The stereocontrolled synthesis of the title alkylaminoepoxide was achieved starting from (3S)-hydroxy-γ-butyrolactone by efficient utilization of the Hofmann rearrangement followed by intramolecular oxazolidinone ring formation as a key step.
- Murakami, Masahiro,Hinoue, Kazumasa,Nakagawa, Kazuya,Monden, Yoshiko,Furukawa, Yoshiro,Katsumura, Shigeo
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- Process for the reduction of amino acids and the derivatives thereof
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A process is disclosed for reducing amino acids and derivatives thereof Compounds of formula (I), in which n=0 or 1 and R1, R2, R3, R4, R5 and R6 have the meanings given in the description, are reduced to the corresponding amino alcohols of formula (II): the formula (I) compounds are converted in a first step, in at least one alcohol and with the addition of acid and heat to an ester, this process producing a reaction mixture containing the ester; the ester is converted in a second reaction step with alkali or alkaline earth borohydride to compounds of formula II. By specifying that the second step be carried out without isolating the ester from the reaction mixture and by using alkali or alkaline earth borohydrides which are not activated, the invention facilitates the production from amino acids and their derivatives of the correponding alcohols in a simple "single vessel" process, with high yields and in such a way as to preserve a given centre of chirality. Applications: synthesis components, preparation of optically active compounds splitting of racemic compounds. STR1
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- Method of producing 3-amino-2-hydroxy-1-propanol derivatives
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The present invention has for its object to provide an efficient and economical method for producing an 3-amino-2-hydroxy-1-propanol derivative and an oxazolidinone derivative derived therefrom, both of which are of use as intermediates for the production
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- Synthesis of the HIV-proteinase inhibitor Saquinavir: A challenge for process research
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The task of process research, namely developing efficient, economically and technically as well as ecologically feasible syntheses in time, is demonstrated on the HIV-proteinase inhibitor Saquinavir (1), a complex molecule comprising six stereo-centres. Based on the first 26-step research synthesis furnishing a 10% overall yield, process research established a new, short 11-step synthesis affording a 50% overall yield.
- G?hring, Wolfgang,Gokhale, Surendra,Hilpert, Hans,Roessler, Felix,Schlageter, Markus,Vogt, Peter
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p. 532 - 537
(2007/10/03)
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- Enantiomerically pure 3-amino-2-hydroxy and 5-amino-4-hydroxy acids from D-isoascorbic acid
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The chirospecific synthesis of 3-amino-2-hydroxy aldehyde or acid units is an important issue in the context of synthetic strategies directed towards the construction of biologically relevant target molecules such as amino sugars, antibiotics, enzyme inhi
- Melon, D.,Gravier-Pelletier, C.,Merrer, Y. Le,Depezay, J. C.
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p. 585 - 593
(2007/10/02)
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