The structural architecture present in marine toxin azaspiracid - 20 stereocenters, 9 rings, 3 separated spirocenters - has attracted considerable synthetic attention. Our efforts toward the synthesis of azaspiracid have led to the completion of both C₁-C₂₆ northern and C₂₇-C₄₀ southern halves. Herein, the
synthesis of southern FGHI ring system...
The potassium salts of a series of 1-vinylcycloalk-3-en-l-ols were found to undergo ring expanding [1, 3]-sigmatropic shifts at 25° when dissolved in hexamethylphosphoramide (HMPA) or 1, 2-dimethoxyethane (DME) with 18-crown-6. The yields and reaction rates were compared with those of the corresponding Siloxy-Cope ring expansions. These anionic cases showed about...
A tracer method utilizing stable activable tracers (involving rare earth nuclides with short-lived t[subscript 1/2] < 1 day} activation products) for tracing fluid bound substances in fresh water is explored. Simulated laboratory studies showed these tracers (Dy and in) when chelated with diethylenetriamine2entaacetic acid a7i1W to be stable ( <20%)...
Many pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers
(PBDEs), and polycyclic aromatic hydrocarbons are persistent, bio-accumulative, and
toxic. These semi-volatile organic compounds (SOCs) can undergo atmospheric
transport and deposition in cold, remote ecosystems. A better understanding of their
accumulation in the fish of these ecosystems is important to better predict...
Two studies were conducted involving rare earth elements. In the
first study, the use of rare earth diethylenetriaminepentaacetic acid
(DTPA) complexes as stable actiable tracers, a method of stable-isotope
tracing with post-sampling neutron activation analysis, was explored.
The persistence of rare earth DTPA complexes in estuarine waters was
measured in...
The two sulfur isotopomers of sulfur trioxide, ³²S¹⁶O₃ and ³⁴S¹⁶O₃, have been studied via high resolution infrared and Coherent anti-Stokes Raman (CARS) spectroscopy. The v₁ symmetric SO stretching Q-branches observed by the latter are quite different, being especially complex for ³²S¹⁶O₃ Understanding this band structure required analysis of infrared-active hot...
Chemistry of preparing dense film from solution deposition is explored with several cases in this thesis. Surface dense structure, conversion at melting point, and ion exchange in aqueous solution are the main topics covered here for the thin films of aluminum oxide phosphate and tin dioxide. Thin film density, optical...
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2.1 XRD patterns of crystallization behavior of ALPO (Al:P=1:0.6)
as a function of
Fungi have long been used for discovery of new chemical scaffolds. In the clinical setting, the fungal natural products penicillin, statins, and cyclosporine have revolutionized medicine to treat diseases and infections. In the environment, fungal natural products have been used as herbicides, fungicides, and insecticides to protect crops, livestock, and...
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8. IC50 curve of 8,8’-bijuglone against human colon carcinoma (HCT-116) .............21