Physical Sciences and Mathematics Commons^™

Field And Smog Chamber Studies Of Agricultural Emissions And Reaction Products, Derek J. Price

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Agricultural emissions are an important contributor to atmospheric aerosol. These emissions include nitrogen containing organic compounds, primarily as amines, which have not been well investigated to date. Although there have been several studies that have looked at the emission of gas phase amines, there are only a few studies that have focused on ambient amine-based aerosol. There have also only been a handful of smog chamber studies that have investigated amine aerosol chemistry. Kinetic studies have looked at the reactions of amines with OH and ozone. However, amine reactions with nitrate radical (NO₃) are not well understood. Several …

Studies On The Roles Of Atp In Nitrogenase Catalysis, Wei Wu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogenase is the enzyme that catalyzes the reduction of nitrogen to ammonia in a reaction requiring MgATP hydrolysis. Two component proteins of nitrogenase are the iron protein (Fe protein) and the molybdenum-iron protein (MoFe protein).

Nitrogenase contains two nucleotide binding sites. During catalysis, the Fe protein binds two MgATP first. The conformational changes induced upon MgATP binding allow the Fe protein to associate with the MoFe protein. After the formation of the Fe protein-MoFe protein complex, a single electron is transferred from the Fe protein to the MoFe protein, an event that is coupled to MgATP hydrolysis in the Fe …

Synthetic Studies Toward Key Portions Of The Didemnins, Ok-Soon Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three different synthetic approaches toward N-[(2SR, 4S) - 4-hydroxy-2,5-dimethyl-3-oxohexanoyl]-Lleucine methyl esters were carried out by use of i) aldol condensation and amination ii) Claisen condensation and soft acid coupling reaction iii) methylation of Hia-Leu derivative in relatively high yields. (4S)-3-[(2SR, 4S)-2,5-Dimethyl-1,3-dioxo-4-(methoxyethoxy-methyloxy)hexyl]-4-(1-methyletheyl-2-oxazolidinone was prepared by the reaction of aldol condensation of lithium enolate of Evans' chiral auxilary in 80:20 diastereomeric ratio. A new method for the synthesis of (4S)-4-(t-butoxycarbonyl)amino-5-methyl-3-oxoheptanoic acid ethyl ester (Statone) was developed by the reaction of Boc-leucine with Meldrum's acid, followed by transesterification and decarboxylation in modest yield. Other a-amino acids also were applied to this methodology in …

Synthetic Studies Toward B-Alkylthiolanthionines, Hwa-Ok Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Synthetic routes toward a B-alkylthiolanthionine derivative, as found in the quinomycin depsipeptide antibiotics, have been studied through a sequence involving as the key intermediates and steps (a) (S) - Z-[(benzyloxycarbonyl)amino]-3,3-dimethoxy-l-propanol (2), prepared from N-benzyloxycarbonyl-L-serine in 3 or 4 steps, (b) N-benzyloxycarbonyl- 0 - tetrahydropyranyl-B,B-(ethylsulfinylethylthio)-alaninol (4a), converted from 2, and (c) attempted Lewis acid catalyzed replacement of alkylsulfinyl function by thiol moiety of cysteine, which gave undesired products. Stability of protecting groups used in this study, which are N,0-isopropylidenyl and tetrahydropyranyl functions in N-protected-L-serinol 20 or 26, under acidic conditions was found to play an important role in determining the optical …

Studies Toward The Synthesis Of A- And B- Mercapto Alanine Derivatives, And Of A,B- And B, B- Dimercapto Alanine Derivatives, Aldean James Kolar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A convenient, economical, large scale synthesis of N-acetyldehydro-alanine (a-acetamidoacrylic acid) and its methyl ester was developed via a sequence of N-chlorination-dehydrochlorination. The method was extended to the synthesis of the corresponding N-benzoyl, N-phenylacetyl and N-benzyloxycarbonyl derivatives.

The conversion of a-methoxy-N-acetyl alanine derivatives to the corresponding a-mercapto alanine derivatives, using zinc chloride and an appropriate mercaptan, was investigated. Methyl a-methoxy-N-acetyl-D, L-alaninate was successfully converted to the a-acetylthio derivative, in 24% yield; however, a 90% yield could be obtained by treatment of the dehydroalanine derivative with hydrogen chloride gas in neat thiolacetic acid.

A facile conversion of the a-acetylthio derivative to the …