Th.--Méd.--Paris, 1883? / Thèse de concours. N ° 3.

The threading polyintercalators are based on a 1,4,5,8-naphthalenetetracarboxylic diimide (NDI) unit that binds DNA via threading intercalation with two imide groups situated in different DNA grooves. In order to extend this strategy to bind DNA with higher affinity and more programmable specificity, it was envisioned that the linkers connecting the NDI units had to be rigidified. Thus a rigid, spiro-cyclic linker was designed and synthesized in the context of a bisintercalator, C1. The new linker has several sites for possible addition of functional groups as recognition elements. DNAse I footprinting results showed that C1 has a higher binding affinity (K[subscript D] ~ 10⁻⁷ M) toward 5'-GGTACC-3' sequence than the previously developed dimer G₃K, which has a flexible linker. NMR structural analysis of the C1-d(CGGTACCG)₂ complex has revealed the versatility of threading polyintercalation based on NDI moieties by verifying the binding of the C1 linker in the minor groove with two NDI units intercalating between GpG steps. The observed binding specificity of C1 is the result of interplay of different factors, such as overall linker length, electrostatic and hydrophobic complementarity to their preferred grooves. The fact that C1 and G₃K can target the same DNA sequence via different grooves, but with different linker structures, prompted us to explore the possibility of creating cyclic bisintercalating molecules. The first example, CBI-1, has been efficiently synthesized through a solid phase synthesis strategy, in which Gly₃Lys, a major groove recognition element for d(GGTACC)₂, was linked at one side and ([Beta]-Ala)₃Lys, a perfect match for a 4-base pair span in the minor groove, was connected on the other side. A dissociation kinetics study on poly(dGdC) indicated a slow dissociation process for CBI-1. Data from DNAse I footprinting and NMR structural studies confirmed that CBI-1 forms a tightly bound complex with DNA d(CG GTAC CG)₂, in which two NDI units intercalate between GC pairs, with linkers interacting with the major and minor grooves simultaneously. CBI-1 also exhibits improved sequence specificity compared to the linear dimer G₃K by only binding 5'-GGTACC-3' sequence. All the results demonstrate that cyclic threading intercalation is a new and effective approach to specifically target DNA sequences. / text

The reaction of Ph2PCH2CH(R)CN (R = H, CH3) and M(CO)6 (M = Cr, Mo, W) with an excess of NaBH4 in ethanol provides excellent yields of cis-coordinated(CO)4M[(Ph)2PCH2CH(R)CH2NH2] complexes. Phosphorus nmr spectra of the reaction mixtures indicate that the products arise from phosphine containing precursors. These precursors have been isolated and identified as the phosphine-imidate complexes, (C0)4M[(Ph)2PCH2CH(R)C(OC2H5)NH]. The corresponding phosphine-amine complexes are obtained when these complexes are subsequently reduced with NaBH4. This suggests that the nitrile groups have been activated toward reduction by nucleophilic attack by ethanol on the CN carbons. Reactions of (CO)4W[(C6H5)2PCH2CH(CH3) CH2NH2] and (CO)4W[(C6H5)2P(CH2)2C(0C2H5)NH] with (C6H5)3P and (C6H5)P(CH3)2 indicated that the nitrogen portion of the bidentate ligand can be replaced by phosphorus. For (C6H5)P(CH3),-r-both replacement reactions were complete within 48 h providing a cis/trans ratio of ca. 1.5.

Th. doct.--Chim. des matériaux--Lyon 1, 1992. N°: 249-92. / Bibliogr. p. 137-143. Résumé en français. 1992 d'après la déclaration de dépôt légal.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

New cyclic 1,3-diazaphospholidine-2,4,5-triones were synthesised and their solvolytic behaviour was studied. Methanolysis of 2-methylamino (24) and 2-dimethylamino (25) derivatives showed evidence of cleavage of both imide P-N bonds. This indicates that the ring opening in these derivatives is much slower than the second P-N cleavage in the ring-opened intermediate (30, scheme 11). On the other hand, methanolysis of 1,3-dimethyl-2-phenoxy-1,3,2-diazaphospholidine-2,4,5-trione (22) yielded the product of the cleavage of only one P-N bond. This product (26, scheme 9) was relatively stable towards further solvolysis. This was taken by Mulliez8 as evidence for the addition-elimination mechanism of solvolysis, since in such a case 22 would experience the usual rate accelerating effect upon the formation of the pv intermediate with trigonal bipyramidal structure. The crystal structures of 24 and 25 were determined in order to investigate the low reactivity of 24 and 25 to solvolysis. This low reactivity correlates with the small size (92.3 and 91.9° respectively) of their endocyclic N-P-N angle. In the case of these two compounds, this suggests that the driving force towards the formation of the pv trigonal bipyramidal intermediate is reduced. Aminolysis of 22 with ammonia and p-anisidine resulted in products which indicate that nucleophilic attack takes place exclusively at the phosphorus atom. In the aminolysis with p-anisidine, both P-0 bond cleavage (displacement of phenol, 43) and ring P-N bond cleavage (44) products were obtained. This can be explained in terms of pseudorotation of the initially formed pv intermediate (22A, scheme 23). The aminolysis of 22 with ammonia yielded exclusively the ring-retained P-OPh bond cleavage product (23). This indicates that pseudorotation of the initially formed pv intermediate (22A, scheme 20) is much faster than endocyclic P-N bond cleavage. Finally,amminolysis of 22 with benzylamine was performed.As reported by Mulliez8, this reaction yielded the product (45) of the initial C-N cleavage, followed by ring closure Acidolysis studies were carried out in anhydrous TFA. These studies indicated that the low reactivity towards nucleophilic attack of 2-amino (23), 2-methylamino (24),2-dimethylamino (25) and 2- p-anisidino (43) derivatives may also be accounted for by the lowered electrophilicity of their phosphorus atom. Finally, within the cyclic 1,3-diazaphospholidine-2,4,5-trione series the reactivity of the various compounds was found to be vastly different, depending on which substituents were present on the exocyclic N atom. Part of the work reported in this thesis has been published; viz.; Phosphoric Carboxylic lmides. Part 6. Structure and Reactivity of 1 ,3,2-diazaphospholidine4,5-diones; Crystal Structure of 1,3-Dimethyl-2-methylamino-1,3,2-diazaphospholidine-2,4,5- trione,Alan T. Hutton, Tomasz A. Modro, Margaret L. Niven, and Sonia Scaillet, J. Chem. Soc. Perkin Trans. II, 17 (1986).

No description available.

Th. doct.--Chimie des matériaux--Lyon 1, 1992. / Bibliogr. p. 147-155.

The synthesis of some imides including bis-maleimides, bis-citraconimides, and bis-nadimides containing four phenylene rings, some of which are novel, is reported. These compounds were purified using preparative high performance liquid chromatography giving compounds of a high purity not commonly observed for monomers of this type. Chapter 2 describes the results of the synthesis and purification of the compounds. The unsaturated imides were heated under nitrogen to obtain polymers. Characterisation of both the monomers and polymers by a variety of techniques is described. The major impurity in the crude bis-citraconimides was isolated and characterised. It was found to be a structural isomer of the desired compounds, the citraconimide-itaconimide mixed imide. Chapter 3 describes the study of the bis-imides, both impure and pure samples, using differential scanning calorimetry. The purity of the compounds was shown to affect temperatures at which both liquifaction and polymerisation of these monomers occurred. Within the series of pure bis-maleimides and citraconimides studied it is noted that those bearing m-substituted rings liquified at much lower temperatures, and samples of these were apparently much less crystalline. Polymerisation rate was the same for m- and p-isomers, citraconimides were less reactive than maleimides. In very highly pure bis-maleimides a second exothermic reaction was observed. The DSC data obtained was analysed to obtain Arrhenius parameters useful in predicting the relative rates of thermal polymerisation of some pure and impure samples of the compounds. The overall order of reaction was found to vary during the course of the reaction. Chapter 4 describes the thermogravimetric analysis of polymer samples, and the bis-nadimide monomers. The results give some indication of thermal and thermo-oxidative stability of the polymers. Experimental details are given in Chapter 5.

This thesis describes a series of investigations into the amide bond-hydrolyzing activity of bacterial strains RU-KM1, RU-KM3L, RU-KM3S, and RU-OR, which were previously isolated for their ability to hydrolyze hydantoins to amino acids. The main aim of the study was to develop biotransformations with potential application in the production of enantiomerically pure amino acids and related compounds. Several compounds may be used as substrates by biocatalysts for the production of amino acids, such as hydantoins, amino nitriles, and amides. These compounds are not only important for amino acid production, but they may be used for production of other industrially important compounds, such as 2- arylpropionic acids, which are non-steroidal anti-inflammatory drugs. Thus, the ability of the above-mentioned strains to hydrolyze these substrates was investigated, with the view to utilizing the maximum potential of these biocatalysts. The compounds used as substrates in the investigation are all essentially amides. Thus, the ability of the strains to hydrolyze imides, hydantoins, and amides, was investigated. In particular, imides have a structure which is very similar to that of hydantoins, and thus it was an objective of the study to determine whether these strains could hydrolyze imides. Imidehydrolyzing activity has only recently been discovered in microorganisms. Hydantoin conversion involves a two-step hydrolysis reaction which yields, initially, an Ncarbamylamino acid intermediate, and subsequently, an "-amino acid. The hydantoinhydrolyzing enzymes of a Pseudomonas putida strain, RU-KM3S, were characterized in a crude extract preparation and reaction conditions for its biocatalytic application were optimized. The optimum conditions for conversion of 5-methylhydantoin were found to be 3 hours at 40°C, with conversion yields greater than 50% achieved. The enzymes of RU-KM3S demonstrated considerable stability, retaining 80% of their activity after incubation at 40°C for 3 hours. The activities of the enzymes were increased by the addition of a detergent to the extraction medium, suggesting that the enzymes might be membrane-bound. The results of the determination of the metal-dependence of the hydantoinase and N-carbamylase of RUKM3S suggested that these enzymes required metal ions for activity, with metal ions such as Mg²⁺, Mn²⁺, Zn²⁺, and Co²⁺ resulting in activation of the enzymes. However, Cu²⁺ and Fe²⁺ caused inactivation of these enzymes. The stereoselectivity of the enzymes was investigated, and the results suggested that the hydantoinase was non-selective, whereas the N-carbamylase was L-selective. The hydantoin substrate selectivity of RU-KM3S was compared to that of three other hydantoinase-producing bacteria, RU-KM1, RU-KM3L, and RU-OR. The four strains were able to hydrolyze all of the seven substrates tested. However, there was a difference in activity levels between crude extract preparations and whole cells, with crude extracts generally showing higher activity than whole cells, except in the case of RU-KM1. Some difference was also observed in the order of preference of substrates between whole cells and crude extracts. The preferred substrate for RU-KM1 whole cells was isopropylhydantoin, whereas the crude extract preparation preferentially hydrolyzed p-hydroxyphenylhydantoin. RU-KM3L whole cells achieved a higher conversion yield with isobutylhydantoin, whereas the crude extract achieved a higher yield with 5-t-butylhydantoin. RU-KM3S whole cells and crude extract preferentially hydrolyzed 5-n-butylhydantoin, although the yield was greater with the crude extract. The highest conversion yields were observed with RU-KM3S crude extract, with conversion yields of 71.6% and 100% for n-butylhydantoin and phydroxyphenylhydantoin, respectively.The ability of RU-KM1, RU-KM3L, and RU-KM3S to hydrolyze nitriles, initially to amides and subsequently to carboxylic acids, was investigated. These strains were demonstrated to be unable to utilize acrylonitrile, propionitrile and benzonitrile as nitrogen sources, but were able to hydrolyze acrylonitrile, propionitrile and acetonitrile, in resting cell reactions. Nitrile hydrolysis was demonstrated to be inducible in all three strains, and the enzyme system responsible for nitrile hydrolysis was proposed to be a nitrile hydratase-amidase system. Amidase activity in the four bacterial strains was investigated. The ability of RU-KM1, RUKM3L, RU-KM3S, and RU-OR to utilize amides as a nitrogen source was investigated, and the results showed that propionamide was a good nitrogen source for all four of the strains. Amide-hydrolyzing activity, by resting cells, was shown to be inducible by propionamide in all four strains. RU-KM3S demonstrated superior amide-hydrolyzing ability in that it hydrolyzed propionamide, acetamide, and acrylamide to a greater extent than the other strains. Resting cells of RU-KM1 and RU-OR were demonstrated to have the ability to hydrolyze the imide substrate, succinimide, and this imidase activity was found to be inducible. These strains were also able to utilize this imide as the sole source of nitrogen for growth, which is a novel finding, as to date, bacteria have only be reported to utilize imides as a carbon source. The identity of the enzyme system responsible for succinimide hydrolysis is not yet clear. In conclusion, the hydantoin-hydrolyzing enzymes of RU-KM3S have been shown to be possibly membrane associated, which is a novel finding that has also been proposed in three other hydantoinase-producing strains in our laboratory. This study has shown that the Ncarbamylase of RU-KM3S is L-stereoselective, which, to our knowledge, is the first report of an L-stereospecific N-carbamylase in a Pseudomonas putida. Publication of these findings is already in progress. This is the first report on the study of imide hydrolysis in either an Agrobacterium tumefaciens or a Pseudomonas sp., and publications reporting these results are in preparation.