Inaugural-Dissertation--Berlin, 1897. / Vita.

No description available.

The study of some acylurea derivatives of 2-amino-3-alkylamino- and -3-arylamino-1,4-naphthoquinones was undertaken to determine the course of reaction under conditions similar to those used by J. R. Hoover and A. R. Day to prepare 2-alkyl-1H-naphth[2,3-d] imidazole-4.9-diones from 2-acylamino-3-amino-1,4-naphthoquinones.

The major forms of cytochrome P-450 protein induced by phenobarbital (P-450[b]) and 3-methylcholanthrene (P-450[c]) have been isolated, purified to electrophoretic homogeneity and fully characterised with respect to substrate specificity. The purified cytochrome P-450[c] was used as antigen in the preparation of sheep polyclonal antibodies, which were used for the immunological detection, characterisation and quantification of the haemoprotein. The N1-substituted antifungal agents, ketoconazole, miconazole and clotrimazole, have been shown to be potent in vitro inhibitors of both the phenobarbital-induced cytochrome P-450- and the 3-methylcholanthrene-induced cytochrome P-448-dependent rat hepatic mixed-function oxidases. All three drugs were more potent inhibitors of the phenobarbital-induced activities in microsomal systems, as well as in reconstituted systems comprising purified NADPH-cytochrome P-450 reductase and cytochrome P-450[b] or P-450[c]. Ketoconazole was the weakest inhibitor and the least selective for the former haemoprotein. All three antimycotic agents elicited type II difference spectra with microsomes from both phenobarbital- and 3-methylcholanthrene-induced rats, as well as with both purified haemoprotein preparations. Miconazole and clotrimazole, and to a lesser extent ketoconazole, have been shown to decrease the magnitude of the type I spectral perturbation of hexobarbital with phenobarbital-induced microsomes. These observations indicate that, although the primary mechanism of inhibition involves reversible binding to haem, an additional interaction with the apoprotein or substrate (type I) binding site is involved and may contribute to the isoenzyme selectivity displayed by all three compounds. When administered systemically to rats, all three antifungal agents stimulated the hepatic microsomal mixed-function oxidases, particularly those activities associated with the phenobarbital and/or pregnenolone-16a-carbonitrile-induced cytochromes P-450. This was confirmed by Western blotting employing anti-cytochrome P-450[p] (PB[2C]) and anti-cytochrome P-450[b]. Administration of the planar benzimidazole 2-amino-3-methylimidazo-(4,5-f)-quinoline (IQ), a food mutagen and carcinogen, in contrast to the globular antifungal agents, selectively induced the cytochromes P-448, especially the high spin form (cytochrome P-450[d]).

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No description available.

Thèse--Méd.--Reims, 1972. / Bibliogr. p. 67.

<p> Nitric oxide has been implicated in a number of biological processes, the majority of them involving iron nitrosyl complexes. The urgency then is to further study and characterize these complexes to further the understanding of biological mechanisms. However, the chemical sensitivity of these species precludes the purification and isolation of these compounds which, unfortunately, has directed the trend to merely detecting the presence of these compounds rather than isolating them. To this day, a large number of Electron Paramagnetic Resonance (EPR) detectable, biological compounds have not been isolated.</p> <p> To this end, the series of biologically relevant compounds of the form Fe(NO)2(L)2 [ L = imidazole 1, 1-methylimidazole (1-MeIm) 2, 4-methylimidazole (4-MeIm) 3, benzimidazole (benzim) 4, and 5,6-dimethylbenzimidazole (56benzim) 5 ] have been synthesized by direct reaction of the appropriate imidazole ligand with Fe(NO)2(CO)2. The compounds were extremely air sensitive, both in solution and as a dry solid. This hindered attempts to purify these compounds and so, infra red (IR), nuclear magnetic resonance (NMR) and EPR spectroscopic studies were undertaken of 2:1 reaction mixtures of the appropriate imidazole ligand and Fe(NO)2(CO)2. These studies revealed that the rapid substitution of the carbonyl ligands is facilitated by a catalytic, 17-electron, electron transfer chain mechanism (ETC), where the imidazole ligand acts to oxidize the 18-electron complex into the active 17-electron Fe(NO)2(CO)2+ species.</p> <p> In the course of the EPR study of 2, crystals formed that were suitable for single-crystal, X-ray diffraction. The compound crystallizes with a monoclinic unit cell, in the C2/c space group with unit cell dimensions: a= 13.985(5) Å, b = 11.529 (5) Å, c = 15.471(4) Å, α= 90°, β= 91.72(2)°, γ = 90°, V = 2493(2) Å^3, Z = 8. During the course of study of 6, crystals suitable for single crystal X-ray diffraction were obtained. The compound crystalizes with a monoclinic unit cell, in the P2/c space group and unit cell dimensions: a= 11.707(9) Å, b = 8.1783 (5) Å, c = 17.2489 (13) Å, α= 90°, β= 106.562 (1)°, γ = 90°, V = 1583.0 (2) Å^3 A, Z = 2.</p> <p> A relatively new mass spectrometry (MS) procedure was utilized for the reaction mixtures of 1 - 5, which involved a combination of electrochemical oxidation and electrospray. The method proved very useful, yielding data that could not be obtained by other MS techniques. Oligomeric species of the form L-[(Fe(NO)2L]x (x = 2,3,4,5 or 6), were also detected by MS for each compound reaction mixture. The oligomers involved linear chains of iron dinitrosyl fragments linked via the imidazole nitrogens. However, it is believed that these oligomers are produced as a result of the conditions met by the mass spectrometer.</p> <p> A reaction of Fe(NO)2(PPh3)(CO) with 1-MeIm was also performed in hopes of producing a more stable mono-substituted complex. However, the reaction also proceeded via an Electron Transfer Chain (ETC) pathway to produce Fe(NO)2(PPh3)2 6.</p> / Thesis / Master of Science (MSc)

No description available.

Chelation of first-row transition metals has many useful properties in the biomedical and industrial fields due to the stabilizing and/or property-altering effects that certain chelates can induce in these metals. One such useful design principle for these chelates is the addition of bulky steric groups which can have an added effect on these properties. Chapter I will explore the origins of these effects and show examples of how these effects are leveraged to produce useful complexes in a variety of applications. In Chapter II, we will discuss our choice of ligand design and the development of related synthetic procedures for all organic portions of the complexes. In Chapter III, we then study the effects of the series of bulky ligands with Mn2+ and Zn2+ on the formation of thermodynamically and kinetically inert complexes and investigate the subsequent effects on redox properties. Chapter IV furthers this investigation with Fe2+ and Co2+ using the bulkiest and least bulky versions of our ligand, where these metal complexes are investigated for the effects on redox properties and spin states. Lastly, a brief appendix details work performed on pyridine-imidazole systems bound to Mn2+ for their potential use in water oxidation catalysis.