Date of Graduation
Eberly College of Arts and Sciences
Bjorn C. Soderberg.
A novel route to cyclopenta[b]quinoline-1-ones and -ols has been developed. Substituted cyclopenta[b]quinolin-1-ones were prepared by thermal ring-expansion of substituted N-BOC protected 4-(2-aminophenylethynyl)-4-hydroxy-2-cyclobuten-1-ones forming the corresponding 2-aminophenylmethylidene substituted 4-cyclopentene-1,3-diones. Deprotection of the amine resulted in spontaneous condensation to give cyclopenta[b]quinolin-1-ones. Sodium borohydride reduction of these products produced cyclopenta[b]quinolin-1-ols. The key step in the sequence is a thermally induced ring-expansion of 4-(2-aminophenylethynyl)-4-hydroxy-2-cyclobuten-1-ones. Changing the amino protecting group had no effect on the ring size selectivity of the thermal ring expansion. The thermal ring expansion of the corresponding nitro derivative suggests that electron withdrawing substituents may alter the selectivity of the ring formation. The attempted base mediated, copper mediated, copper catalyzed and palladium catalyzed indolization reaction were not further examined since the desired products were not obtained. The N-iodosuccinimide, N-chlorosuccinimide mediated and palladium catalyzed ring expansion reactions were also not further examined. The copper acetate catalyzed indolization of the N-acetyl derivative may lead to the preparation of novel 2-substituted indoles. In the Cul mediated reactions with N-benzyl the project was dropped since the starting material was difficult to synthesize. A novel route to indoloquinones has been developed. This methodology may lead to the synthesis of a natural product, as well as several novel indoloquinones.
Zehr, Peter S., "Synthesis of novel alkaloids using squaric acid esters" (2005). Graduate Theses, Dissertations, and Problem Reports. 2273.