CAS: Chemistry: Undergraduate Honors Theses
Permanent URI for this collection
Browse
Recent Submissions
Item Abietic acid in the synthesis of unnatural alkaloids(2014-04) Gale-Day, Zachary JohnThe synthesis of unnatural alkaloid-type products from abietic acid was explored. In order to synthesize these products the protection of the carboxylic acid was achieved followed by a selective dihydroxylation of the C-ring was followed by oxidative diol cleavage. Using the dione yielded a reductive aminocyclization followed. This reaction was first explored using 4-methoxybenzylamine and after optimization the alkaloid-type product was synthesized in a 34% yield. Using the optimized conditions a small library of analogues were synthesized utilizing different primary amines.Item Inter- and Intramolecular Cobalt (I)-Catalyzed [2+2+2] Cyclizations of Bisnitriles(2014-04) Audet, Megan AnnThe cobalt (I)-catalyzed intramolecular [2+2+2] cyclization reactions previously investigated by Vollhardt were successfully applied to alkynylbisnitrile species in the formation of novel annulated pyridazines. This chemistry demonstrates the first successful formation of an N,N- bond through a [2+2+2] cyclization pathway. Nitrogen linkers with different protecting groups were incorporated into the alkynylbisnitrile species, and were used as a site of selective deprotection and diversification of the cyclized scaffold. Using this methodology, two novel ureas were formed from the annulated pyridazines with high yields (88-93%), indicating the feasibility of the development of a diverse small molecule library using this chemistry. Expanding upon the success in the intramolecular cyclizations, the intermolecular incorporation of alkynes and nitriles with arylbisnitriles was examined. Although the intermolecular incorporation of diphenylacetylene was found to only provide trace amounts of the desired product, favoring the trimerization product, benzonitrile was found to incorporate well, forming the corresponding 1,2,4-triazine regioselectively (44%).Item Synthesis of Unnatural Alkaloid-Type Compounds from Terpenoid-Derived Natural Products by Nitrogen Insertion via Aminocyclization(2013-04) Szeto, Howard Chung-HoThe synthesis of unnatural alkaloid-type compounds from natural products using an oxidative alkene cleavage, reductive aminocyclization sequence was explored. The natural product cholesterol, as the initial model, was treated with ozone to cleave the 5, 6-alkene, forming the B-ring seco ketoaldehyde. Various reaction conditions were then tested with 4-methoxybenzylamine as primary amine source to optimize the reductive aminocyclization reaction. It was found that running this reaction in THF at 60˚C for one hour in the microwave provided a yield of 70%. Using this protocol, the reaction of cholesterol derived ketoaldehyde with various other primary amines gave mixed results.