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Aztreonam and Aztreonam-Avibactam
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Few interactions occur between aztreonam and other drugs. Co-administration of metronidazole parenteral solutions and the injectable aztreonam may lead to the development of pink color in their intravenous admixtures (Thakur et al., 1991). Nitrite ions may be produced in metronidazole solutions at the time of preparation or during storage by the effects of temperature and light. Under acidic pH conditions, the aminothiazole moiety of aztreonam can be diazotized by the nitrite ion contributed by metronidazole solutions. The diazotized molecule, in turn, reacts with another aztreonam molecule by diazo coupling. The result is a pink-colored product (Thakur et al., 1991). An interaction between aztreonam and nafcillin sodium in 0.9% sodium chloride injection or 5% dextrose injection stored in glass or plastic containers has been reported (Riley and Lipford, 1986). Admixtures of aztreonam and nafcillin sodium may become cloudy and show evidence of a fine precipitate.
Analytical Chemistry of Rubins
Published in Karel P. M. Heirwegh, Stanley B. Brown, Bilirubin, 1982
Karel P. M. Heirwegh, Stanley B. Brown
Diazo procedure. Caffeine reagent (7 mℓ) was mixed with 2 mℓ sample (bilirubin dissolved in 0.1 M NaOH, or an aqueous solution of conjugated bilirubin), 1 mℓ freshly prepared diazo reagent was added to the mixture, and after reaction for 10 min at 20°C the azo color was determined at 530 nm.
The Modification of Carboxyl Groups
Published in Roger L. Lundblad, Claudia M. Noyes, Chemical Reagents for Protein Modification, 1984
Roger L. Lundblad, Claudia M. Noyes
Diazo compounds have proved useful for some time in the esterification of the carboxyl groups of proteins. This is particularly true of diazomethane. The use of this compound was reviewed 15 years ago by the late Philip Wilcox,10,11 and we are not aware of the extensive use of this compound during the past decade. Various α-keto diazo derivatives have proved particularly fruitful in the study of acid proteinases. Rajagopalan, Stein, and Moore12 demonstrated that pepsin was inactivated by diazoacetyl-l-norleucine methyl ester. During the course of these studies, it was observed that cupric ions greatly enhanced both the rate and specificity of the modification. Originally it was suggested that cupric ions blocked non-specific reaction with carboxyl groups not at the active site. Subsequently it was shown that cupric ions and diazoacetyl-norleucine methyl ester formed a highly reactive species, presumably a copper-complexed carbene, which then reacted with a specific protonated carboxyl group at the active site of pepsin.13,14 The modification of carboxyl groups in a variety of acid proteinases with a variety of α-keto diazo compounds is shown in Table 1. These diazo compounds are by no means specific for carboxyl group modification in protein. Benzyloxycarbonyl-phenylalanyldiazomethylketone has been shown to modify cathepsin B,, presumably by reaction with the active site sulfhydryl group.15 Other possible side reactions of α-keto diazo compounds have been reviewed by Widner and Viswanatha.16 These side reactions result primarily from the oxidative modification of tryptophan, methionine, tyrosine, and cystine. These side reactions can be virtually obviated by vigorous exclusion of oxygen from the reaction and the addition of an oxygen scavenger (e.g., Na2S2O4).
Current and emerging technologies for the timely screening and diagnosis of neonatal jaundice
Published in Critical Reviews in Clinical Laboratory Sciences, 2022
Mercy Thomas, Ronda F. Greaves, David G. Tingay, Tze Ping Loh, Vera Ignjatovic, Fiona Newall, Michelle Oeum, Mai Thi Chi Tran, Anushi E. Rajapaksa
Other modified wet chemistry methods are based on enzymatic reactions, including the bilirubin oxidase and vanadate oxidase methods, where there is little interference from hemolysis to determine direct bilirubin [75]. Bilirubin oxidase determines the various fractions of bilirubin based on the enzyme reactivity at different pH in the presence or absence of anionic detergents. The resulting decrease in absorbance at 450 nm is linearly related to the concentration of serum bilirubin fractions and has better specificity for jaundice detection compared to diazo methods [76]. The Vanadate oxidase method can be replaced for the bilirubin oxidase method; however, these method principles are not commonly available as part of commercial hits and therefore require each laboratory to develop an in-house method. Thus, the commercial diazo method principle remains the most widely available analytical method in clinical chemistry laboratories [77].
Imidazopyridine-fused [1,3]diazepinones: modulations of positions 2 to 4 and their impacts on the anti-melanoma activity
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Paul Le Baccon-Sollier, Yohan Malki, Morgane Maye, Lamiaa M. A. Ali, Laure Lichon, Pierre Cuq, Laure-Anaïs Vincent, Nicolas Masurier
For 4-azidobutyl derivatives 16–18, introduction of the azido group was studied using two strategies. Initially, the azido group was introduced in the final step of the sequence by diazo transfer on the free amino derivative 23, using imidazo-1-sulfonyl azide in presence of potassium carbonate and copper sulfate (Scheme 4). The imidazolyl reactant was preferred to the classical sodium azide, because this reagent is more stable and easier to handle26. The diazo transfer reaction proceeded smoothly and led to several by-products, which complicated the purification step. Compounds 16–18 were finally isolated in 10% yields from compound 1 (5-step procedure). In a second approach, Boc-6-azido-Nle-OH 29 was prepared from Boc-Lys-OH, according to the procedure described by Shoonen et al.15 Acylation of 1 with compound 29 led to compound 3 h in 71% yield. The Boc group was then deprotected, using a mixture of trifluoroacetic acid/dichloromethane (50/50 v/v) and the resulting diamine was cyclized with 4-bromobenzaldehyde to offer compound 16 in 30% yield. Compared with the initial 5-step sequence, the 4-step procedure led to a better global yield from compound 1 (21% vs 10%) and compounds were easier to purify. Finally, alkyne derivative 22 was prepared in 94% yields by acylation of the amine 23 with pentynoic acid (Scheme 4).
The molecular rationale for therapeutic targeting of glutamine metabolism in pulmonary hypertension
Published in Expert Opinion on Therapeutic Targets, 2019
Thomas Bertero, Dror Perk, Stephen Y. Chan
Due to our advancing appreciation of enhanced glutamine metabolism in numerous hyperproliferative pathologies throughout cancer, PH, and other cardiopulmonary diseases, GLS, as well as glutamine metabolism in general, is being explored as a significant target for therapeutic interventions [39,165]. The emergence of small molecule inhibitors such as BPTES, CB-839, and compound 968 has led to new avenues of metabolism-targeted drugs that block GLS activity and glutaminolysis. However, such strategies are not straightforward, given the toxic side effects of certain glutamine antagonists, for instance, DON (6-diazo-5-oxo-l-norleucine), stemming from its broad inhibition of several other enzymes related to glutamine utilization [166,167]. In addition, the recent development of drugs that target the glutamine transporter SLC1A5 as well as GLUD and aminotransferase has emerged. However, while there has been tremendous growth in our understanding of glutamine metabolism, there remain hurdles to overcome before glutamine metabolism pathway inhibitors can be clinically applied.