The azomethine ylide strategy for β-lactam synthesis. An evaluation of alternative pathways for azomethine ylide generation

Intramolecular Dipolar Cycloaddition Reactions of Azomethine Ylides

“…195 Attempts to promote the intramolecular cycloaddition reaction using the related β-lactam 530 were unsuccessful. 196 The β-lactam 530 was heated in acetic anhydride to allow O-acylation and formation of the required iminium ion; however, only the acetate 531 was isolated from the reaction mixture.…”

Hydrates and Solid-State Reactivity: A Survey of β-Lactam Antibiotics

“…The majority of the remaining structures contained water molecules which were hydrogen bonded to one another as well as the drug. In REFCODE OBIVUQ, 18 two molecules of a monobactam derivative are bridged by the water molecule with C --OÁÁÁH bonds. The water also hydrogen bonds to neighboring water molecules through OÀHÁÁÁO bonds, as shown in Figure 5.…”

The azomethine ylide strategy for β-lactam synthesis. A comprehensive mechanistic evaluation

“…Precedent for this type of racemisation process does exist within the β-lactam area, 15 and this is more appropriately discussed in detail in the accompanying paper. 11 We have also probed the kinetic properties of two cycloaddition reactions using MeCN as solvent. The first involved a reactive dipolarophile (NPM) and the other using a significantly less reactive trap (methyl dithiobenzoate) (Scheme 3).…”