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This report regards the research conducted in the synthesis of 2,5-disubstituted-1,3,4-oxadiazoles as potential insecticides which are closely related to the known insecticide DOWCO 416R, 2,5-bis(2,4-dichlorophenyl)-1,3,4-oxadiazole. The following compounds were synthesized: 2-(2,4-dichloro-5-nitrophenyl)-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole, (2-(2,4-dichloro-5-nitrophenyl)-5-phenyl-1,3,4-oxadiazole, 2-(2,4-dichloro-5-aminophenyl)-5-aminophenyl)-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole and 2-(2,4-dichloro-5-aminophenyl)-5-phenyl-1,3,4-oxadiazole. From the commercially available starting material, 2, 4-dichlorobenzoic acid, preparation of the above compounds involved nitration, reduction, esterification, preparation of monoacylhydrazines, preparation of substituted diacylhydrazines and preparation of 2, 5-disubstituted-1, 3, 4-oxadiazoles. All these compounds were characterized via NMR and infrared spectroscopy. In addition, this report includes discussion and recommendations concerning the experimental procedures and conditions for the preparation of these compounds.

The generality of the [4+1] cyclopentene annulation was demonstrated by the total synthesis of (±)-pentalenene and its C-9 epimer which were prepared in a stereocontrolled manner in analogy with the synthesis of (±)-isocomene, (±)-hirsutene and (±)-pentalenic acid. The key features of this synthesis involved preparation of acid 161, its conversion to diazoketone 148, intramolecular cyclopropanation of this substance to vinylcyclopropane 163 and the vinylcyclopropane-cyclo pentene rearrangement of several derivatives of 195 to triquinanes 147, 146, 197, and 204. A detailed study of temperature, conformation, and electronic effects on the diradical scission of vinylcyclopropanes of type 195 was carried out under pyrolytic conditions. Conclusive results regarding conformational stability at C-9 were also attained and exploited in the context of stereocontrol at this center. As a result of this synthesis, several new methods of functional transformations emerged, such as the selective reduction of conjugated esters and a new method of preparation of enolethers from carboxylic acids. / Master of Science / incomplete_metadata

(1). An improved method for synthesizing bicyclo (2,2,1) hepta-2,5-diene-7-spiro-1'-cyclopentane (5) has been developed. Thermal reaction of compound (5) with neat iron pentacarbonyl under nitrogen atmosphere affords the corresponding cage dimer (6). Some aspects of the syntheses, spectra, and chemistry of compound (5) and (6) are discussed. (2). A structure isomer of decamethyldodecahedrane (C₃₀H₄₀), molecule (11), is expected to be synthesized via thermal reaction of iron carbonyl complexes with compound (10). An intermediate in this synthesis, 2,2- tetramethylene-1,4-dibromobutane (9) was efficiently synthesized starting from cyclopentanone. Some aspects of the syntheses, spectra, and chemistry of compound (1) to (9) will be discussed.