A method of preparing a derivative of optically active azetidin-2-one
申请人:Takasago International Corporation
公开号:EP0742223A1
公开(公告)日:1996-11-13
To prepare the compound (1'R, 3S)-3-(1'-tri-substituted silyloxyethyl) azetidin-2-one, (2S, 3R)-2-aminomethyl-3-hydroxybutyric acid is reacted with an alcohol in the presence of at least one compound chosen from the group consisting of thionyl chloride, hydrogen chloride and p-toluene sulfonic acid, thereby obtaining a salt of the corresponding ester. The salt is reacted with a tri-substituted silane in the presence of a metallic catalyst, thereby protecting the hydroxy group of the ester and then reacted with a base, thereby obtaining an ester of (2S, 3R)-2-aminomethyl-3-(tri-substituted silyloxy) butyric acid. Subsequently, the ester is transformed into lactam in the presence of a Grignard reagent or a metal amide, thereby obtaining (1'R,3S)-3-(1'-tri-substituted silyloxyethyl)azetidin-2-one. This compound provides a useful base for preparing β-lactam type antimicrobial agents such as carbapenem type agents.
Asymmetric synthesis of β2-amino acids: 2-substituted-3-aminopropanoic acids from N-acryloyl SuperQuat derivatives
作者:James E. Beddow、Stephen G. Davies、Kenneth B. Ling、Paul M. Roberts、Angela J. Russell、Andrew D. Smith、James E. Thomson
DOI:10.1039/b707689d
日期:——
Conjugateaddition of lithium dibenzylamide to (S)-N(3)-acryloyl-4-isopropyl-5,5-dimethyloxazolidin-2-one (derivedfrom l-valine) and alkylation of the resultant lithium beta-amino enolate provides, after deprotection, a range of (S)-2-alkyl-3-aminopropanoic acids in good yield and high ee. Alternatively, via a complementary pathway, conjugateaddition of a range of secondary lithium amides to (S)
Method of preparing a derivative of optically active azetidin-2-one
申请人:Takasago International Corporation
公开号:US05712388A1
公开(公告)日:1998-01-27
To prepare the compound (1'R,3S)-3-(1'-tri-substituted silyloxyethyl)azetidin-2-one, (2S,3R)-2-aminomethyl-3-hydroxybutyric acid is reacted with an alcohol in the presence of at least one compound chosen from the group consisting of thionyl chloride, hydrogen chloride and p-toluene sulfonic acid, thereby obtaining a salt of the corresponding ester. The salt is reacted with a tri-substituted silane in the presence of a metallic catalyst, thereby protecting the hydroxy group of the ester and then reacted with a base, thereby obtaining an ester of (2S,3R)-2-aminomethyl-3-(tri-substituted silyloxy)butyric acid. Subsequently, the ester is transformed into lactam in the presence of a Grignard reagent or a metal amide, thereby obtaining (1'R,3S)-3-(1'-tri-substituted silyloxyethyl)azetidin-2-one. This compound provides a useful base for preparing .beta.-lactam type antimicrobial agents such as carbapenem type agents.