153469-86-4Relevant academic research and scientific papers
124. 1,3-Cycloadditions to Highly Substituted, Strained Double Bonds: Spiro-β-lactams from α-Methylidene-β-lactams by Reactions with Diphenylnitrilimine, Acetonitrile Oxide, Nitrones, and Diazomethane
Strauss, Arthur,Otto, Hans-Hartwig
, p. 1823 - 1830 (1997)
Substituted dihydropyrazole-spiro-β-lactams and isoxazolidine-spiro-β-lactam derivatives are regio- and stereoselectively prepared by 1,3-cycloadditions between substituted α-methylidene-β-lactams and diazomethane, nitrones, or the in-situ-prepared dipoles 'diphenylnitrilimine' and acetonitrile oxide. These reactions represent examples for 1,3-cycloadditions to the highly substituted, strained double bonds of α-methylidene-β-lactams, and they need special experimental conditions as all reaction products are relatively unstable. Especially in solution, the reverse reaction is highly favoured. Regioselectivity and stereoselectivity of the reactions are elucidated mainly by NMR techniques such as 2D-INEPT, ATP, and NOE experiments.
Transformation of 4-acetoxy-3-vinylazetidin-2-ones to 3-(1-hydroxyethyl)azetidin-2-ones and 3-ethylideneazetidin-2-ones intermediates for carbapenem antibiotics
Neary, Anthony D.,Burke, Catherine M.,O'Leary, Aisling C.,Meegan, Mary J.
, p. 501 - 522 (2007/10/03)
4-acetoxy-3-vinylazetidin-2-one and 4-acetoxy-3-isopropenylazetidin-2-one were transformed to the carbapenem intermediates 4-acethoxy-3-(1-hydroxyethyl)azetidin-2-ones and 4-acethoxy-3-[2-(2-hydroxypropyl)]-4-acetoxyazetidin-2-ones respectively by a sequence of direct bromohydrin formation followed by reductive debromination. Transformation of 4-formyl-3-vinylazetidin-2-ones to 4-acetoxy-3-ethylideneazetidin-2-ones was also carried out. We have also demonstrated the synthesis of a 6-vinylcarbapenem.
Preparation of α-Methylene and α-Ethylidene β-Lactams via the Ester Enolate-Imine Condensation Using β-(Dialkylamino) Esters as Starting Materials: Scope and Synthetic Applications
Alcaide, Benito,Esteban, Gemma,Martin-Cantalejo, Yolanda,Plumet, Joaquin,Rodriguez-Lopez, Julian,et al.
, p. 7994 - 8002 (2007/10/02)
A new, simple procedure for the preparation of appropriately substituted α-methylene and α-ethylidene β-lactams via the ester enolate-imine condensation is described.The method is based on the use of lithium 3-(dialkylamino) ester enolates as synthetic eq
