344930-73-0Relevant academic research and scientific papers
Kinetics and Mechanism of Hydrolysis of N-Acyloxymethyl Derivatives of Azetidin-2-one
Valente, Emilia,Gomes, Jose R. B.,Moreira, Rui,Iley, Jim
, p. 3359 - 3367 (2007/10/03)
The pH-independent, acid-catalyzed and base-catalyzed hydrolyses of N-acyloxymethylazetidin-2-ones all occur at the ester function. The pH-independent hydrolysis involves rate-limiting alkyl C-O fission and formation of an exocyclic β-lactam iminum ion. This iminium ion is then trapped by water at the exocyclic iminium carbon atom, rather than at the β-lactam carbonyl carbon atom, to form the corresponding N-hydroxymethylazetidin-2-ones. Calculations carried out at the B3LYP/6-31+G(d) level of theory also support that nucleophilic attack by water takes place at the exocyclic carbon rather than at the β-lactam carbonyl carbon of the iminium ion. The mechanism for the acid-catalyzed pathway involves a preequilibrium protonation, probably at the β-lactam nitrogen, followed by rate-limiting alkyl C-O fission with formation of an exocyclic iminum ion. The base-catalyzed hydrolysis involves rate-limiting hydroxide attack at the ester carbonyl carbon. These results imply formation of a β-lactam system containing a positively charged amide nitrogen atom that hydrolyzes via a pathway that preserves the β-lactam structure in the product and provide further evidence that cleavage of the β-lactam C-N bond is not as facile as is commonly imagined.
Design, synthesis and stability of N-acyloxymethyl- and N-aminocarbonyloxymethyl-2-azetidinones as human leukocyte elastase inhibitors
Clemente,Domingos,Grancho,Iley,Moreira,Neres,Palma,Santana,Valente
, p. 1065 - 1068 (2007/10/03)
A series of N-acyloxymethyl- and N-aminocarbonyloxymethyl derivatives of 2-azetidinones, 3, with different substituent patterns at the β-lactam C-3 and C-4 positions, were designed as potential mechanism-based inhibitors for human leukocyte elastase and f
