The syntheses of β-lactams from zinc enolates of N,N-disubstituted α-aminoacid esters and imines: Substituent and solvent effects
作者:Fred H. van der Steen、Henk Kleijn、Johann T.B.H. Jastrzebski、Gerard van Koten
DOI:10.1016/s0040-4039(01)80304-x
日期:——
A high yield synthesis of 3-(N,N-disubstituted)amino-β-lactams based on the condensation of zinc enolates with imines is reported. With the activated Me3SiC≡CC(H)NSiMe3 (3b) exclusively trans-β-lactams are formed, whereas with PhC(H)NMe (3a) there are substituent and solvent effects on the product distribution.
Reaction of silyl ketene acetals with N-trimethylsilyl imines: a route to N-unsubstituted azetidin-2-ones
作者:Ernest W. Colvin、Daniel G. McGarry
DOI:10.1039/c39850000539
日期:——
Reaction of N-trimethylsilylimines with silylketeneacetals in the presence of ZnI2 and t-butyl alcohol, followed by treatment in situ of the intermediate N-silyl β-aminoesters with MeMgBr, leads to N-unsubstitutedazetidin-2-ones in good yield.
A FACILE ENTRY TO 3-(1-HYDROXYETHYL)-2-AZETIDINONES FROM METHYL (<i>R</i>)-3-HYDROXYBUTANOATE BASED ON THE ESTER ENOLATE-ALDIMINE CONDENSATION
作者:Toshiyuki Chiba、Masako Nagatsuma、Takeshi Nakai
DOI:10.1246/cl.1984.1927
日期:1984.11.5
The reaction of the dianion of methyl (R)-3-hydroxybutanoate with the N-silylimine generated from trimethylsilylpropynal afforded (3R,4S)-3-[(R)-1-hydroxyethyl]-4-trimethylsilylethynyl-2-azetidinone as the major product, of which the stereochemistry was assigned through its stereospecific conversion to the (+)-4-acetoxy derivative.
Stereoselective one-pot syntheses of trans-3-amino-β-lactams from zinc enolates of N-protected α-aminoacid esters and imines.
作者:Fred H van der Steen、Johann T.B.H Jastrzebski、Gerard van Koten
DOI:10.1016/s0040-4039(00)87909-5
日期:1988.1
A new one-pot synthesis of 3-aminoβ-lactams that is based on the condensation of simple imines with zinc enolates of disilyl protected glycine esters is reported. Isolated yields are high and a trans-selectivity is observed.
The present invention relates to a novel process for the preparation of ethyl 3S-[[4-[[4-(aminoiminomethyl)phenyl]amino]-1,4-dioxobutyl]amino]-4-pentyno ate and pharmaceutically acceptable acid addition salt thereof.