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Part I: Phase-Transfer Reactions Of Enones. Part Ii: Synthetic Applications Of Dihydrothiopyrans., David William. Pillon
Part I: Phase-Transfer Reactions Of Enones. Part Ii: Synthetic Applications Of Dihydrothiopyrans., David William. Pillon
Electronic Theses and Dissertations
Self-condensation of crotonaldehyde under base-catalyzed phase-transfer conditions leads to 4,6-dimethyl dihydropyrancarboxaldehyde or dihydro-o-tolualdehyde, depending only on the concentration of aqueous hydroxide used. Dihydro-o-tolualdehyde is formed when the hydroxide concentration is between 70% (17.5N) and 25% (6.25N). 4,6-Dimethyl dihydroyrancarboxaldehyde first appears at a hydroxide concentration 30% (7.5N) and it continues to be produced at concentrations as low as 5% (1.25N). The range, over which the product completely changes from one to the other, is small (30% NaOH to 25% NaOH). It appears that, as the hydroxide concentration decreases, the water concentration in the organic phase is sufficient to alter the action …
Part I: Field Desorption Mass Spectrometry Of Alkali Metal Cryptates. Part Ii: Stereochemical Differentiation Of Alcohol Derivatives By Various Mass Spectrometric Techniques., Mei-Kuen. Au
Electronic Theses and Dissertations
Part I. Field desorption (FD) mass spectra have been obtained from a series of alkali metal cryptates formed from {2.2.2}-, {2.2.1}- and {2.1.1}-cryptands with Li('+), Na('+) and K('+) salts of Cl('-), Br('-), I('-), OTs('-) and BPh(,4)('-). Stabilities of these complexes under FD conditions are compared with their thermodynamic stabilities in solution. Differences in these stabilities are attributed to the lack of solvation of ions under FD conditions. A marked anion effect is also observed in FD spectra. This effect is correlated with the recombination energy of the released cation and anion in the gaseous state. Part II. Acid phthalates from …
Part I: Formation Of Complexes With Divalent Cations In Field Desorption Mass Spectrometry. Part Ii: Polyhydroxyl Matrices In Field Desorption Mass Spectrometry Of Sodium Salts Of Organic Acids., Wing-Fung. Sun
Electronic Theses and Dissertations
Part I. Sugars and other polar molecules are shown to form doubly-charged complexes with divalent ions which are detected by field desorption mass spectrometry (FDMS) with reasonable intensities. Cationization of sucrose, raffinose, and stachyose with Ba('2+) ions generates a series of doubly-charged complex ions, including {M + Ba}('2+). Similar treatment of several polyether mixtures with Ca('2+) gives abundant {M + Ca}('2+) ions which show approximately the molecular weight distribution of the oligomers. Such doubly-charged ions have the advantage of extending the effective mass scale of conventional mass spectrometers without inherent loss of sensitivity. Part II. Field desorption (FD) mass spectra …