FTIR study of five complex β‐lactam molecules

Abstract

Five monocyclic 4-benzoyl-4-phenyl-beta-lactam derivatives in carbon tetrachloride solutions were studied by FTIR spectroscopy. The Fourier self-deconvolution method was applied to enhance the resolution of the FTIR spectra. The calculated spectra of these five compounds, which were obtained by quantum mechanical methods, were compared with FTIR data. A complete assignment of the vibrational frequencies in the 4000-400 cm(-1) range was made. Several vibrations were selected as being useful to characterize the beta-lactam ring. Substituents on N1 (p-methoxyphenyl) and C3 (methyl, phenyl, maleimidyl, and phthalimidyl) on the beta-lactam ring increase the amide resonance and the planarity of the ring. The optimized geometry along with the total electric charges on the four atoms of the ring support an antibiotic action mechanism by a nucleophilic attack of the enzymes on the carbonyl carbon atom of the beta-lactam ring.

Antibiotic mediated synthesis of gold nanoparticles with potent antimicrobial activity and their application in antimicrobial coatings

“…3C, shows the characteristic FTIR spectrum of cefaclor with bands at 1770 cm À1 (C]O group of four membered ring lactams and COOH functional group), 1697 cm À1 (C]O group), 1605 cm À1 (primary amine), 1505 cm À1 (C]C ring stretch) and 1415 cm À1 (C-N stretch). [74][75][76] The characteristic b-lactam ring vibrations were also observed at 1418, 1395 and 1357 cm À1 in curve 1, Fig. 3C, as suggested by Gil et al 76 The band at 1625 cm À1 for cefaclor reduced gold nanoparticles (curve 2, Fig.…”

“…[74][75][76] The characteristic b-lactam ring vibrations were also observed at 1418, 1395 and 1357 cm À1 in curve 1, Fig. 3C, as suggested by Gil et al 76 The band at 1625 cm À1 for cefaclor reduced gold nanoparticles (curve 2, Fig.…”

“…[74][75][76] The characteristic b-lactam ring vibrations were also observed at 1418, 1395 and 1357 cm À1 in curve 1, Fig. 3C, as suggested by Gil et al 76 The band at 1625 cm À1 for cefaclor reduced gold nanoparticles (curve 2, Fig. 3C) could be assigned to an amine group, which is shifted to a higher wavenumber compared to the primary amine of pure cefaclor (1604 cm À1 ), indicating that the primary amine group of cefaclor acts as the reducing and capping agent for the synthesis of gold nanoparticles.…”

Quantum chemical study of several monocyclic complex β‐lactam C‐3, C‐4, and N‐derivatives, and β‐ring model molecules

“…For compound 2 in chloroform solution was necessary to apply the Fourier deconvolution to resolve the complex band of the carbonyl region. A more detailed description of this part was previously reported by us 32.…”

“…Because a deep knowledge of the β‐lactam nucleus is required to make a rational design of a new series of β‐lactam antibiotics, as well as to establish a structure–activity relationship, and as a continuation of our previous works 6, 32, a detailed vibrational study was carried out on these model molecules and the β‐lactam ring modes were characterized. Thus, from the information obtained, several more complex monocyclic derivatives with potential antibacterial activity were analyzed (Fig.…”