Acetoacetoxy ethyl methacrylate (AAEM) resin, a new scavenger for primary amines in the presence of secondary amines

The stability of enamine crosslinks formed from acetoacetate/amine in synthetic hydrogels

“…The reaction between primary amines and acetoacetates can be efficient in organic solvents and lead to essentially quantitative formation of enamines (or 3-aminocrotonates) [39]. In aqueous media, enamine formation is often inefficient and the equilibrium enamine concentration is sensitive to solution conditions [35,38,40,41,49,50].…”

“…The reaction, which has been employed to crosslink coatings [35e38] and scavenge primary amines [39], is known to be reversible, with enamines favored in organic environments, but often disfavored in aqueous media where the equilibrium enamine concentration is sensitive to solution conditions such as pH, reactant concentration and the presence of organic cosolvents [40e42]. As our experiments had shown significant crosslinking between A70 and polyamines within capsules under physiological conditions, it appeared that there may be additional factors favoring enamine formation in such aqueous systems.…”

Solid-phase synthesis of 4-methylene pyrrolidines and allylic amines using palladium-activated allylic linkers

“…2). 39 Selective scavenging of primary amines from secondary amine products was achieved using acetoacetoxy methacrylate (AAEM) resin 52, 40,41 and secondary amines were removed from the reaction mixtures containing tertiary amine products using isocyanate resin 53. 39 Once excess starting amines had been removed, a relatively simple column chromatography provided the pure allylic amines, although one could imagine using SPE methods to separate the basic products from residual ligand and catalyst impurities if higher throughput was required.…”

Moderne Trennverfahren zur effizienten Aufarbeitung in der organischen Synthese

“…Eine gute Wahl sind polymergebundene Isocyanate,231 da sich bei der Abfangreaktion keine Nebenprodukte bilden. Sie eignen sich gut zum Entfernen von nichtumgesetzten primären und sekundären Aminen bei der Synthese von Amiden und Sulfonamiden227, 232–234 sowie zur Trennung von sekundären Aminen von tertiären Aminen und tertiären Aminoalkoholen. Auch polymergebundene Aldehyde und Säurechloride werden als elektrophile Harze eingesetzt 232.…”