653-89-4Relevant academic research and scientific papers
Further studies on the catalysis of hydrolysis and aminolysis of benzylpenicillin by metal chelates
Tomida,Schwartz
, p. 331 - 335 (1983)
It was suggested previously that the very rapid catalysis of benzylpenicillin hydrolysis and aminolysis by zinc ion and tris(hydroxymethyl)aminomethane (tromethamine) was mediated by a ternary complex in which the metal ion not only held the substrate and
THE USE OF LIPOPHILIC BETA-LACTAM ANTIBIOTICS AND CARBOXYLATE ESTERS FOR THE TREATMENT OF BACTERIAL INFECTIONS WITHIN CITRUS AND OTHER PLANT SPECIES
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Paragraph 0035-0036; 0048, (2020/08/05)
Disclosed is method for converting a beta-lactam antibiotic into a “masked” beta-lactam antibiotic to permit it to cross the waxy cuticle of a plant and then subsequently unmasking the beta-lactam and converting it into an active beta-lactam antibiotic in
REACTION OF XeF2. PART 7. SYNTHESIS OF 6-FLUOROBIOTIN METHYL ESTER
Huang, Xiaoling,Blackburn, Barry J.,Janzen, Alexander F.
, p. 145 - 150 (2007/10/02)
The synthesis of 6-fluoro-d-biotin methyl ester and its characterization by (1)H and (19)F nmr and elemental analysis is described.Analogous reactions of XeF2 with tetramisole and benzylpenicillin methyl ester were carried out but monofluorinated products
Penicillin Biosynthesis: Direct Biosynthetic Formation of Penicillin V and Penicillin G
Baldwin, Jack E.,Abraham, Edward P.,Burge, Geoffrey L.,Ting, Hong-Hoi
, p. 1808 - 1809 (2007/10/02)
The enzyme isopenicillin N synthetase is able to convert directly the dipeptides, phenoxyacetylcysteinylvaline and phenylacetylcysteinylvaline into penicillin V and G respectively; these are however very slow compared with substrates of the α-aminoadipoyl or adipoylcysteinylvaline type.
A COMPARISON OF THE ANTIBACTERIAL AND β-LACTAMASE INHIBITING PROPERTIES OF PENAM AND (2,3)-β-METHYLENEPENAM DERIVATIVES THE DISCOVERY OF A NEW β-LACTAMASE INHIBITOR. CONFORMATIONAL REQUIREMENTS FOR PENICILLIN ANTIBACTERIAL ACTIVITY
Keith, D. D.,Tengi, J.,Rossman, P.,Todaro, L.,Weigele, M.
, p. 2445 - 2458 (2007/10/02)
The antibacterial potencies of 2a and 4 are shown to be diminished considerably from their penam analogues, penicillin G (1a) and mecillinam (3).Despite this, 2a is a substrate for bacterial β-lactamases, and compounds 6a, 8 and 10 were found to be β-lactamase inhibitors.Penicillin-binding protein (PBP) studies indicate that penicillin G and mecillinam have much greater affinity to these enzymes than the (2,3)-β-methylenepenam analogues.Based on a comparison of hydrolytic stabilities, it is proposed that the change in biological properties is due to conformational differences between the two types of penam nuclei.The cyclopropyl methylene of 2a and 4 blocks the side chain from forming an oxazolone with the β-lactam carbonyl.Hence, activation of the β-lactam is prevented and the molecules are rendered less active.We thus conclude that 19 is the biologically active conformation of penicillin antibacterials, and futher suggest that the interaction of such antibiotics with their bacterial enzyme targets involves intermediates such as 25-27.
Metal-ion Catalysed Hydrolysis of Some β-Lactam Antibiotics
Gensmantel, Nigel P.,Proctor, Philip,Page, Michael I.
, p. 1725 - 1732 (2007/10/02)
The metal(II)-ion catalysed hydrolysis of some penicillin and cephalosporin derivatives in water at 30 deg C shows saturation kinetics.A 1:1 complex is formed between the metal ion and penicillin which is attacked by hydroxyde ion up to 1E8 fold faster than the unco-ordinated compound.The site of co-ordination of the penicillins and copper(II) ions is the β-lactam nitrogen and the carboxylate group.The association constants for the cephalosporins and metal ions are greater than those for the penicillins but the transition states for the cephalosporin reaction with hydroxyde ion bind less tightly to metal ions.The order of rate enhancement brought about by the metal ion is CuII > ZnII > NiII ca.CoII.The metal ions are thought to stabilise the tetrahedral intermediate formed by hydroxide ion attack on the β-lactam.Some comments are made about metal ions as electrophilic catalysts in enzymes.
Chemical ionization mass spectrometry of β lactam antibiotics
Mitscher,Hollis Showalter,Shirahata,Foltz
, p. 668 - 675 (2007/10/04)
Chemical ionization (CI) mass spectra are described for methyl esters of eight clinically significant penicillins and their breakdown products. These substances give spectra with very few fragment ions and contain easily discernible protonated molecule ions. The main cleavage reaction is postulated to involve a retro 2 + 2 Diels Alder type fragmentation of the β lactam ring liberating one fragment (m/e=174) that is characteristic of the penicillin nucleus and a second fragment that is molecule specific, as it contains the elements of the side chain. The other fragment ions, though interesting, are of minor intensity. The free acids, on the other hand, fragment more extensively because of their relative instability and lack of volatility. These spectra resemble electron impact spectra more closely and, though they encode more structural information, are less reproducible from run to run. The ease with which the esters can be made and the relative simplicity of their CI mass spectra make this method significant for the identification and characterization of β lactam antibiotics.
