High-precision instrumental neutron activation analysis has
been used to determine Al, Na, Mn, Sc, Cr, Fe, Co, and Ni in a
suite of more than 500 chondrules from 26 distinct meteorites. These
meteorite specimens represent the H, L, LL and C chemical classes
and most of the petrologic types. In...
A procedure for evaluating the precision of atomic absorption
measurements is presented and applied to 21 elements under varying
instrumental conditions. The experimental relative standard deviations
(RSD's) in absorbance obtained from repetitive measurements made
with a high resolution voltmeter and on-line computer, are compared
to those predicted by a recently...
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...
Basalts of both Eocene and Miocene age from several groups
along the Oregon and Washington coasts have been analyzed for some
major, minor, and trace elements using instrumental neutron activation analysis (INAA). The rare earth element (REE) patterns observed
in these samples are used for comparisons within the groups studied...
The ethyl acetate extract of the culture filtrate of the marine Ascomycete,
Leptosphaeria oraemaris (Linder) yielded a novel metabolite
designated by the common name leptosphaerin. An x-ray crystallographic
structure analysis was disproved by the synthesis of 3-acetoxy-S-(1,2-dihydroxyethyl)-
3-pyrrolin-2-one 1, starting with N,N-dibenzylhydroxylamine
47 and D-mannitol 44. Oxidation of 47 followed...
Several approaches to the synthesis of methymycin were
investigated. Segment A (39), containing functionality corresponding
to C-9, 10, and 11 of methynolide was made in
six steps from propionaldehyde in an overall yield of 37%.
Oxidation of 34 with silver nitrate gave 35 which, upon hydroxylation
with hydrogen peroxide, gave...
This thesis describes a study of the synthesis, stereochemistry,
and reactivity of cobalt(III) cysteinato (CyS) and related thiolato complexes.
The preparation of [Co(en)₂CyS]⁺ resulted in a product solution
containing a mixture of diastereomers in the ratio 2.3:1 (Δ:A). The isomers were separated by ion exchange chromatography, and
their absolute configurations...
Hydrated cobalt(II) and nickel(II) trifluoromethanesulfonates have
been prepared by a previously reported procedure, and have been
characterized for the first time as [ Co(H₂O)₆] (CF₃SO₃)₂H₂O and [Ni(H₂O)₆] (CF₃SO₃)₂. These formulations are based on analyses,
near-infrared spectra, and on measurements of the ligand field
electronic spectra and the magnetic susceptibilities. The...