𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Theoretical calculations of β-lactam antibiotics. III. AM1, MNDO, and MINDO/3 calculations of hydrolysis of β-lactam compound (azetidin-2-one ring)

✍ Scribed by J. Frau; J. Donoso; F. Muñoz; F. García Blanco

Publisher
John Wiley and Sons
Year
1992
Tongue
English
Weight
905 KB
Volume
13
Category
Article
ISSN
0192-8651

No coin nor oath required. For personal study only.

✦ Synopsis

Semiempirical AM1, MINDO/3, and MNDO methods have been used in the study of the alkaline hydrolysis of P-lactam antibiotics through a base-catalyzed, acyl-cleavage, bimolecular mechanism. In this work, the hydroxyl ion has been chosen as nucleophilic agent and the azetidin-2-one ring like a model of 0-lactam antibiotic. The MIND0/3 method does not predict correctly the energies of small rings. This, together with the fact that, like MNDO, it cannot detect the occurrence of hydrogen bonds, gives rise to uncertain estimates of energy barriers. The AM1 method can be considered the most suitable for studying the hydrolysis of P-lactam compounds.

📜 SIMILAR VOLUMES

Theoretical Calculations of β-Lactam Ant
Theoretical Calculations of β-Lactam Antibiotics. Part VI. AM1 calculations of alkaline hydrolysis of clavulanic acid
✍ Juan Frau; Josefa Donoso; Francisco Muñoz; Francisco García Blanco 📂 Article 📅 1994 🏛 John Wiley and Sons 🌐 German ⚖ 989 KB

The gas-phase basic hydrolysis of clavulanic acid (a) was studied by using the AM1 semi-empirical method. The results obtained show that the hydroxyethylidene side chain at C(2) is pivotal to the stability of the different reaction products involved. The products with an open oxazolidine ring are mo

Theoretical Calculations of β-Lactam Ant
Theoretical Calculations of β-Lactam Antibiotics. Part VII. Influence of the solvent on the basic hydrolysis of the β-lactam ring
✍ Juan Frau; Josefa Donoso; Francisco Muñoz; Francisco Gracia-Blanco 📂 Article 📅 1996 🏛 John Wiley and Sons 🌐 German ⚖ 571 KB

We used semi-empirical and ab initio calculations to investigate the nucleophilic attack of the OHion on the 8-lactam carbonyl group. Both allowed us to detect reaction intermediates pertaining to proton-transfer reactions rather than the studied reaction. We also used the PM3 semi-empirical method

Theoretical calculations of β-lactam ant
Theoretical calculations of β-lactam antibiotics. V. AM1 calculations of hydrolysis of cephalothin in gaseous phase and influence of the solvent
✍ J. Frau; J. Donoso; F. Muñoz; F. García Blanco 📂 Article 📅 1993 🏛 John Wiley and Sons 🌐 English ⚖ 697 KB

A comprehensive study on the gas-phase alkaline hydrolysis of cephalosporins by using the semiempirical AM1 method was carried out. Cephalothin was the model compound used on account of the presence of a good leaving group at C(3'). According to the results obtained, the hydrolysis process takes pla