The Synthesis of the Fluorescence Probe, 12-(1-Pyrenyl)dodecanoic Acid

The synthesis of the fluorescence probe, 12-(1-pyrenyl)dodecanoic acid, was accomplished by the Wittig reaction between 1- -pyrenecarboxaldehyde and 10-methoxycarbonyldecyltriphenylphosphonium bromide, followed by hydrogenation of the unsaturated product and hydrolysis of methyl ester. The Wittig reaction was carried out with sodium methoxide in dimethylformamide, at room temperature and under a N2 atmosphere. This reacion yielded a mixture of 530/o trans .and 47-0/0 cis isomers of 12- (l-pyrenyl)-11- -dodecenoate, as determined . by pulsed Fourier transform NMR technique

The Synthesis of the Fluorescence Probe, 12-(1-Pyrenyl)dodecanoic Acid

The synthesis of the fluorescence probe, 12-(1-pyrenyl)dodecanoic acid, was accomplished by the Wittig reaction between 1- -pyrenecarboxaldehyde and 10-methoxycarbonyldecyltriphenylphosphonium bromide, followed by hydrogenation of the unsaturated product and hydrolysis of methyl ester. The Wittig reaction was carried out with sodium methoxide in dimethylformamide, at room temperature and under a N2 atmosphere. This reacion yielded a mixture of 530/o trans .and 47-0/0 cis isomers of 12- (l-pyrenyl)-11- -dodecenoate, as determined . by pulsed Fourier transform NMR technique

Homologous Hexapeptides

The N-hydr oxysuccinimide esters of N-tritylated tripeptides II-V were coupled with hydroacetates of tripeptide esters VII-IX to correspoding N-tritylated hexapeptide esters XV-XXL The saponification of so obtained compounds followed by detritylation afforded pentaglycyl-B-alanine (XXXIII), pentaglycyl -.y- aminobutyric acid (XXXIV), digly cyl-B- alanyl- diglycyl-B-alanine (XXXV), diglycyl-B-alanyl-diglycyl-y-aminobutric acid (XXXVI), diglycyl- y-aminobutyry l-diglycyl-y-aminobutyric acid (XXXVII), diglycyl- -y-aminobutyryl-glycyl-B-alanyl-y-aminobutyric acid (XXXVIII), and glycyl- B-alanyl-y-aminobutyr yl-glycyl-B-alanyl-y-aminobutyric acid (XXXIX)

Homologous Hexapeptides

The N-hydr oxysuccinimide esters of N-tritylated tripeptides II-V were coupled with hydroacetates of tripeptide esters VII-IX to correspoding N-tritylated hexapeptide esters XV-XXL The saponification of so obtained compounds followed by detritylation afforded pentaglycyl-B-alanine (XXXIII), pentaglycyl -.y- aminobutyric acid (XXXIV), digly cyl-B- alanyl- diglycyl-B-alanine (XXXV), diglycyl-B-alanyl-diglycyl-y-aminobutric acid (XXXVI), diglycyl- y-aminobutyry l-diglycyl-y-aminobutyric acid (XXXVII), diglycyl- -y-aminobutyryl-glycyl-B-alanyl-y-aminobutyric acid (XXXVIII), and glycyl- B-alanyl-y-aminobutyr yl-glycyl-B-alanyl-y-aminobutyric acid (XXXIX)

Free radicals properties of gamma-irradiated penicillin-derived antibiotics: piperacillin, ampicillin, and crystalline penicillin

The aim of this work was to determine the concentrations and properties of free radicals in piperacillin, ampicillin, and crystalline penicillin after gamma irradiation. The radicals were studied by electron paramagnetic resonance (EPR) spectroscopy using an X-band spectrometer (9.3 GHz). Gamma irradiation was performed at a dose of 25 kGy. One- and two-exponential functions were fitted to the experimental data, in order to assess the influence of the antibiotics’ storage time on the measured EPR lines. After gamma irradiation, complex EPR lines were recorded confirming the presence of a large number of free radicals formed during the irradiation. For all tested antibiotics, concentrations of free radicals and parameters of EPR spectra changed with storage time. The results obtained demonstrate that concentration of free radicals and other spectroscopic parameters can be used to select the optimal parameters of radiation sterilization of β-lactam antibiotics. The most important parameters are the constants τ (τ(1(A),(I)) and τ(2(A),(I))) and K (K(0(A),(I)), K(1(A),(I)), K(2(A),(I))) of the exponential functions that describe free radicals decay during samples storage