90696-10-9Relevant academic research and scientific papers
Soluble-polymer-supported synthesis of β-lactams on a modified poly(ethylene glycol)
Annunziata, Rita,Benaglia, Maurizio,Cinquini, Mauro,Cozzi, Franco
, p. 133 - 138 (2007/10/03)
A modified poly(ethylene glycol) (PEG) has been developed for the soluble-polymer-supported synthesis of β-lactams. The monomethylether of PEG (MeOPEG) with an average Mw of 5000 was used as the support, a 4-(3-propyl)phenyl residue as the spacer, and a 4-oxyphenylamino group as the moiety with the reactive functionality. From this modified PEG representative aromatic, heteroaromatic, unsaturated, and aliphatic imines were obtained in high yields by different procedures. The polymer-supported imines were then employed to prepare several β-lactams by enolate/imine condensation and ketene/ imine cycloaddition. Examples of the control of the absolute stereochemistry during the azetidinone ring formation are also reported. The reactions carried out on the polymer-bound imines showed a remarkable similarity to those performed on nonimmobilized imines, both in terms of yields and stereoselectivities. Removal of the β-lactams from the polymer has also been accomplished to directly deliver the N-unsubstituted azetidinones.
β-Tosylethylamine: A Useful Reagent for Preparation of N-Protected Amides, Carbamates, and Related Compounds. Application to Synthesis of β-Lactams
DiPietro, Darren,Borzilleri, Robert M.,Weinreb, Steven M.
, p. 5856 - 5857 (2007/10/02)
Readily prepared β-tosylethylamine (3) can be used to synthesize N-tosylethyl (TSE)-protected amido compounds and β-lactams, which can be deprotected under mild conditions with potassium tert-butoxide.
Reaction of Silyl Ketene Acetals with N-Trimethylsilyl Imines: a Route to N-Unsubstituted Azetidin-2-ones
Colvin, Ernest W.,McGarry, Daniel G.
, p. 539 - 540 (2007/10/02)
Reaction of N-trimethylsilyl imines with silyl ketene acetals 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-unsubstituted azetidin-2-ones in good yield.
N-Trimethylsilyl Imines: Applications to the Synthesis of β-Lactams
Ha, Deok-Chan,Hart, David J.,Yang, Teng-Kuei
, p. 4819 - 4825 (2007/10/02)
Ester enolates and N-trimethylsilyl imines react to afford N-protio-β-lactams.The stereochemical course of the reaction depends on the ester enolate geometry.Therefore (E)-enolates give mainly cis β-lactams while (Z)-enolates give nearly equal mixtures of cis and trans β-lactams.The use of ethyl β-hydroxybutyrate as the ester component allows the preparation of β-lactams of potential use in carbapenem synthesis.The differences in the behavior of N-trimethylsilyl and N-aryl imines in ester-imine condensations are also discussed.
