Thesis (Ph.D.)--Brown University, 2005. / Vita. Thesis advisor: Christoph G. Rose-Petruck. Includes bibliographical references (leaves 95-107). Also available online.

- / -

The investigation on inulin, which forms the subject of the present thesis, is an extension of the earlier work of Irvine and Steele, who placed the study of this polysaccharide on an exact basis.

No description available.

No description available.

No description available.

No description available.

This thesis is divided into two parts. The first part involves the study of molecular structure utilizing Ianthanide induced shift (LIS) and lanthanide induced relaxation (LIR) nuclear magnetic resonance (NMR). It the course of these studies, it was found that the trifluoroethoxy group is a good deactivating group towards lanthanide shift reagents (LSR) and can be used to selectively deactivate multifunctional molecules. The second part of the thesis involves the utilization of liquid-liquid intermolecular transfer (LLIT) dynamic nuclear polarization (DNP) to study the microwave power needed to achieve saturation using deuterated and nondeuterated 2,4,6-tri-tert-butylphenoxy and galvinoxyl radicals, and ¹⁴N labelled, nondeuterated and ¹⁴N labelled, deuterated 4-hydroxy-TEMPO radicals. Also, selective ¹H DNP enhancements for taxol in solid-liquid intermolecular transfer (SLIT) DNP low-to-high field transfer experiments were obtained. Finally, the syntheses of compounds with both a LSR moiety and a nitroxide radical moiety in the same molecule were examined. LLIT DNP transfer experiments for the intramolecular LSR-nitroxide radicals molecular system and the intermolecular LSR—radicals systems were studied. Conclusions based on this study provide new insight regarding approaches for new LIS and DNP studies. / Ph. D.

Yes / In this work, effect of ultrasound on molecular structure development of Polylactide (PLA) was studied. It was found that the intrinsic viscosity of PLA decreased with increasing treating time, temperature and ultrasound time. Different from traditional thermal degradation of PLA, the degradation of PLA under ultrasound treatment showed that chain scission and chain combination of PLA competed with each other in the degradation process, which could be divided into two steps. The mechanism of ultrasound degradation of PLA was proposed. Furthermore, Thermal properties were characterized by DSC to show heat and ultrasound effects on molecular structure development of PLA.

Yes / t-BuOK-mediated rearrangement of 1,3-ketoesters with 2-(azidomethyl) aromatics in a two-step, one-pot telescoped sequence affords β-enaminoketoesters in moderate to good yields. A novel pathway is proposed in which the umpolung of the azide is achieved from electrophilicity to nucleophilicity via deprotonation and undergoes nucleophilic attack onto the 1,3-ketoester.