Invasive fungal infections are a major complication for individuals with compromised immune systems. One of the most significant challenges in the treatment of invasive fungal infections is the increased resistance of many organisms to widely used antifungals, making the development of novel antifungal agents essential. Many naturally occurring products have been found to be effective antimicrobial agents. In particular, saponins with spirostane glycosidic moieties- isolated from plant or marine species- have been shown to possess a range of antimicrobial properties. In this report, we outline a novel approach to the synthesis of a number of functionalized spirostane molecules that can be further used as building blocks for novel spirostane-linked glycosides and present results from the in vitro screenings of the antifungal potential of each derivative against four fungal species, including Candida albicans, Cryptococcus neoformans, Candida glabrata, and the filamentous fungus Aspergillus fumigatus.
Preparation procedures for biologically important benzoylbarbiturates are presented. Several procedures are optimized to cover the preparations of a wide variety of substituted 5-benzoylbarbiturates. To further explore the biological importance of these compounds, multi-gram preparation procedures for nitrophenylhydrazones of benzoylbarbiturates and their corresponding salts with organic amines are discussed. It is demonstrated that these compounds can exist in several tautomeric forms and that the equilibrium in solution can be changed by temperature as well as by the pH of the solution. X-ray structural analysis performed on one of the nitrophenylhydrazones of benzoylbarbiturates fully agrees with the presented spectroscopic studies. AM1 semi-empirical studies show that the enol form is preferred in the gas phase of benzoylbarbiturates over the keto form, which was also confirmed by NMR spectroscopic studies with chloroform as the solvent. Furthermore, AM1 computed structural and electronic properties of the dinitrophenylhydrazone of 4-hydroxybenzoylbarbiturate compared favorably with the X-ray determined structure.
Barbituric acid derivativesBarbituric acid derivatives R 0530Simple, Efficient, High Yield Syntheses of Substituted and Unsubstituted 5-Benzoylbarbituric Acids, and Their Corresponding Schiff Base Phenylhydrazones.-Several procedures for the preparation of biologically important benzoylbarbiturates of type (III), (V), (VII), or (IX) and their phenylhydrazones of type (XI) are presented. It is demonstrated that these compounds exist in several tautomeric forms and that the equilibrium in solution can be changed by temperature as well as by the pH of the solution. The X-ray structural analysis of one of the nitrophenylhydrazones fully agrees with the presented spectroscopic studies. -(JURSIC*, B. S.; NEUMANN, D. M.; BOWDY, K. L.; STEVENS, E. D.; J. Heterocycl. Chem. 41 (2004) 2, 233-246; Dep. Chem., Univ. New Orleans, New Orleans, LA 70148, USA; Eng.) -M. Bohle 36-152
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