Article commenting on the prediction of gas chromatographic retention behavior with mixed liquid phases.

Article on thermochemical investigations of gas-liquid chromatography and partition coefficients of inert solutes on self-associating binary solvent mixtures.

This article discusses excess molar volumes of binary mixtures of cyclohexane and y-butyrolactone with aromatic hydrocarbons.

This article discusses solubility of pyrene in binary solvent mixtures containing cyclohexane.

Article on the solubility of phenylacetic acid in binary solvent mixtures.

Article on the solubility of anthracene in binary solvent mixtures containing dibutyl ether.

This article discusses the solubility of pyrene in binary solvent mixtures containing dibutyl ether.

Article on experimental artifacts and determination of accurate Py values.

This article discusses the effect of solvent polarity on the fluorescence emission fine structures of coronene derivatives.

Article on isentropic compressibility of an ideal ternary solution.

Article on polycyclic aromatic hydrocarbon solute probes and the effect of solvent polarity on the ovalene and benzo[ghi]perylene fluorescence emission fine structures.

Article on polycyclic aromatic hydrocarbon solute probes and fluorescence emission spectra of pyrene, ovalene, benzo[ghi]perylene, and coronene dissolved in liquid tetrabutylammonium sulfonate salts.

Article on polycyclic aromatic hydrocarbon solute probes and fluorescence spectra of pyrene, ovalene, coronene, and benzo[ghi]perylene dissolved in liquid alkylammonium thiocyanate organic salts.

Article on polycyclic aromatic hydrocarbon solute probes and the effect of dissolved oxygen and halogenated solvents on the emission spectra of select probe molecules.

Article on polycyclic aromatic hydrocarbon solute probes and the effect of solvent polarity on the fluorescence emission fine structures of select pyrene and pentaphene derivatives.

In order to explore the N-H stretching region of aliphatic amines, we performed a study of the Raman spectrum of n-propylamine at various concentrations in cyclohexane. Statistical analysis provided evidence of a second symmetric stretching vibration, which we were able to assign to nonhydrogen bonded NH2 groups. To obtain additional evidence on the existence of monomers in n-propylamine and to further study hydrogen bonding and Fermi resonance in aliphatic amines, we extended the investigation to the analysis of the Raman spectrum of this compound over an extended range of temperature in the neat liquid phase. This study corroborated our finding that the peak previously assigned to the symmetric stretching mode of hydrogen bonded amines is actually composed of two bands. Furthermore, trends in both the resolved band parameters and the Fermi resonance analysis were tabulated, allowing one to monitor the change in the N-H valence region with concentration and temperature.

The reaction of chlorodimethylvinylsilane with tertbutyllithium was investigated in the presence of several conjugated dienes. In all cases except with 2,5-dimethylfuran, [2+4] cycloadducts of a silene intermediate are obtained in hydrocarbon solvents. The presence of THF in the reaction mixture suppresses the formation of cycloadducts in favor of 1,3-disilacyclobutanes. In the reaction of dimethylethoxyvinylsilane or dimethylmethoxyvinylsilane with tert-butyllithium the main product is the 1,1-dimethyl2-neopentyl-4-(dimethylalkoxysilyl)silacyclobutane. It is concluded that lithium chloride elimination to give silene intermediates occurs in hydrocarbon solvents. In the presence of strong Lewis bases or when the leaving group on silicon is an alkoxy group, the addition reaction giving a-lithiosilanes occurs and products arising from their coupling reactions are obtained.

This study deals with the (4+2)-cycloaddition reactions of 4-π electron compounds with ketenes. Chloroketenes were generated in situ from the corresponding chlorinated acid chlorides in the presence of the ketenophiles. Chloro-, dichloro- and diphenylketenes reacted with 1-methoxy-3-trimethylsiloxy-l,3-butadiene, and 2,4-bis(trimethylsiloxy)-1,3-pentadiene to yield the corresponding dihydropyrans. The dihydropyrans yielded substituted 4-pyranones on hydrolysis.

Various modern spectroscopies have been utilized with considerable success in recent years to probe the dynamics of vibrational and reorientational relaxation of molecules in condensed phases. We have studied the temperature dependence of the polarized and depolarized Raman spectra of various modes in the following dihalomethanes: dibromomethane, dichloromethane, dichloromethane-d2, and bromochloromethane. Among other observed trends, we have found the following: Vibrational dephasing times calculated from the bend) and (C-Br stretch) lineshapes are of the same magnitude in CI^B^. The vibrational dephasing time of [C-D(H) stretch] is twice as long in CD2Cl2 as in CH-^C^, and the relaxation time of (C-Cl stretch) is greater in CI^C^ than in CD2CI2. Isotropic relaxation times for all three stretching vibrations are significantly shorter in C^BrCl than in CI^C^ or CI^B^. Application of the Kubo model revealed that derived modulation times are close to equal for equivalent vibrations in the various dihalomethanes. Thus, the more efficient relaxation of the A^ modes in CE^BrCl can be attributed almost entirely to the broader mean squared frequency perturbation of the vibrations in this molecule.

Cyclopropanation of the unsaturated fatty acid moieties of membrane phospholipids is a commonly observed phenomenon in a number of bacterial systems. The cyclopropane fatty acids are usually synthesized during and after the transition from exponential growth to stationary phase, or under such environmental conditions as acidic culture pH, low oxygen tension or high salt concentrations. S-Adenosylmethionine, the ubiquitous methyl group donor, provides the methylene bridge carbon in the reaction catalyzed by cyclopropane fatty acid synthase. Also formed in the reaction is S-adenosylhomocysteine, a potent inhibitor of cyclopropane fatty acid synthase, which is degraded by S-adenosylhomocysteine nucleosidase. This work provides evidence for at least two modes of regulation of lactobacillic acid synthesis, the cyclopropane fatty acid formed from cis-vaccenic acid (cis-11,12-octadecenoic acid), in Lactobacillus piantarum.

The reactions of tert-butyl-, sec-butyl-, and n-butyllithium with dimethylfluorovinylsilane include addition to the double bond to give both silene and silenoid intermediates, fluorine substitution, and a novel vinyl substitution. For the tert-butyllithium reaction, product stereochemistry and trapping experiments using both cyclopentadiene and methoxytrimethylsilane show that silenes are not formed in THF. In hexane about 67% of the 1,3-disilacyclobutanes obtained arise from silene dimerization while 33% are formed by silenoid coupling. In hexane the order of reactivity for addition, t-Bu > sec-Bu > n-Bu, is opposite that for fluorine substitution. The vinyl substitution is most significant with secondary alkyllithium reagents including the tert-butyllithium adduct to dimethylfluorovinylsilane and with sec-butyllithium itself. Evidence for the formation of vinyllithium or ethylene in the process could not be obtained.

A study has been conducted for the qualitative and Quantitative analysis of chlorinated organic compounds in water. The study included the adaptation of Amberlite XAD macroreticular resin techniques for the concentration of municipal wastewater samples, followed by GC/MS analysis. A new analytical method was developed for the determination of volatile halogenated organics using liquid-liquid extraction and electron capture gas chromatography. And, a computer program was written which searches raw GC/MS computer files for halogen-containing organic compounds.

This dissertation reports the preparation of several types of anthraquinones structurally related to adriamycin. It describes the synthesis of two types of 2-aminoquinizarin compounds. It also presents two new syntheses of a heterocyclic tetracyclic ring system, similar to the aglicone ring system of adriamycin. A series of 2-aminoquinizarins was prepared by adding several primary amines to quinizarin. Quinizarin was shown to be essentially inert toward secondary amines. Several secondary amine adducts with quinizarin have been prepared, however, by treating the bis-boroacetate ester of quinizarin with the amines. Both types of 2-aminoquinizarin compounds exhibit outstanding potential for possessing antineoplastic activity, and several have been submitted to the National Cancer Institute for testing in their screening program for antineoplastic agents.

Ketene dimethyl thioacetal monosulfoxide was prepared in 68% overall yield in two steps starting from methylmagnesium chloride. The yield of dithioacetic acid was improved significantly by employing tetrahydrofuran as solvent and using elevated temperatures. A one-pot synthesis of ketene thioacetals from alkyl halides was developed and several ketene thioacetals were prepared by this method. Direct oxidation of ketene thioacetals using m-chloroperoxybenzoic acid provided a general route to ketene thioacetal monosulfoxides. In cases where E and Z isomeric ketene thioacetal monosulfoxides were possible, the E/Z isomeric ratio increased as the substituents on the ketene double bond was increased in size.